Altruism

We need scarcely add that the contemplation in natural science of a wider domain than the actual leads to a far better understanding of the actual.' (p. 267,The, Nature of the Physical World.)x PREFACE evolutionary theory was thus chiefly retrogressive, the mighty body of Mendelian researches throughout the world has evidently out- grown the fallacies with which it was at first fostered.As a pioneer of genetics he has done more than enough to expiate the rash polemics of his early writings.To treat Natural Selection as an agency based independently on its own foundations is not to mimimize its importance in the theory of evolution.On the contrary, as soon as we require to form opinions by other means than by comparison and analogy, such an indepen- dent deductive basis becomes a necessity.This necessity is particu- larly to be noted for mankind; since we have some knowledge of the structure of society, of human motives, and of the vital statistics of this species, the use of the deductive method can supply a more intimate knowledge of the evolutionary processes than is elsewhere possible.In addition it will be of importance for our subject to call) attention to several consequences of the principle of Natural Selection!which, since they do not consist in the adaptive modification of specific I forms, have necessarily escaped attention.The genetic phenomena of I dominance and linkage seem to offer examples of this class, the future ' investigation of which may add greatly to the scope of our subject.No efforts of mine could avail to make the book easy reading.I have endeavoured to assist the reader by giving short summaries at the ends of all chapters, except Chapter IV, which is summarized conjointly with Chapter V.Those who prefer to do so may regardChapter IV as a mathematical appendix to the corresponding part of the summary.The deductions respecting Man are strictly in- separable from the more general chapters, but have been placed together in a group commencing with Chapter VIII.I believe no one will be surprised that a large number of the points considered demand a far fuller, more rigorous, and more comprehensive treat- ment.It seems impossible that full justice should be done to the subject in this way, until there is built up a tradition of mathematical work devoted to biological problems, comparable to the researches upon which a mathematical physicist can draw in the resolution of special difficulties.

@book{doi105962bhltitle27468,
    author = "Fisher, Ronald Aylmer",
    title = "The genetical theory of natural selection",
    year = "1930",
    booktitle = "Clarendon Press eBooks",
    abstract = "We need scarcely add that the contemplation in natural science of a wider domain than the actual leads to a far better understanding of the actual.' (p. 267,The, Nature of the Physical World.)x PREFACE evolutionary theory was thus chiefly retrogressive, the mighty body of Mendelian researches throughout the world has evidently out- grown the fallacies with which it was at first fostered.As a pioneer of genetics he has done more than enough to expiate the rash polemics of his early writings.To treat Natural Selection as an agency based independently on its own foundations is not to mimimize its importance in the theory of evolution.On the contrary, as soon as we require to form opinions by other means than by comparison and analogy, such an indepen- dent deductive basis becomes a necessity.This necessity is particu- larly to be noted for mankind; since we have some knowledge of the structure of society, of human motives, and of the vital statistics of this species, the use of the deductive method can supply a more intimate knowledge of the evolutionary processes than is elsewhere possible.In addition it will be of importance for our subject to call) attention to several consequences of the principle of Natural Selection!which, since they do not consist in the adaptive modification of specific I forms, have necessarily escaped attention.The genetic phenomena of I dominance and linkage seem to offer examples of this class, the future ' investigation of which may add greatly to the scope of our subject.No efforts of mine could avail to make the book easy reading.I have endeavoured to assist the reader by giving short summaries at the ends of all chapters, except Chapter IV, which is summarized conjointly with Chapter V.Those who prefer to do so may regardChapter IV as a mathematical appendix to the corresponding part of the summary.The deductions respecting Man are strictly in- separable from the more general chapters, but have been placed together in a group commencing with Chapter VIII.I believe no one will be surprised that a large number of the points considered demand a far fuller, more rigorous, and more comprehensive treat- ment.It seems impossible that full justice should be done to the subject in this way, until there is built up a tradition of mathematical work devoted to biological problems, comparable to the researches upon which a mathematical physicist can draw in the resolution of special difficulties.",
    url = "https://doi.org/10.5962/bhl.title.27468",
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@article{doi101086394551,
    author = "Sturtevant, A. H.",
    title = "Essays on Evolution. II. On the Effects of Selection on Social Insects",
    year = "1938",
    journal = "The Quarterly Review of Biology",
    url = "https://doi.org/10.1086/394551",
    doi = "10.1086/394551",
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The Origin of Species, by Charles Darwin, is part of the Barnes & Noble Classicsseries, which offers quality editions at affordable prices to the student and the general reader, including new scholarship, thoughtful design, and pages of carefully crafted extras. Here are some of the remarkable features of Barnes & Noble New introductions commissioned from today's top writers and scholars Biographies of the authors Chronologies of contemporary historical, biographical, and cultural events Footnotes and endnotes Selective discussions of imitations, parodies, poems, books, plays, paintings, operas, statuary, and films inspired by the work Comments by other famous authors Study questions to challenge the reader's viewpoints and expectations Bibliographies for further reading Indices & Glossaries, when appropriate All editions are beautifully designed and are printed to superior specifications; some include illustrations of historical interest. Barnes & Noble Classics pulls together a constellation of influencesbiographical, historical, and literaryto enrich each reader's understanding of these enduring works.On December 27, 1831, the young naturalist Charles Darwin left Plymouth Harbor aboard the HMS Beagle. For the next five years, he conducted research on plants and animals from around the globe, amassing a body of evidence that would culminate one of the greatest discoveries the history of mankindthe theory of evolution.Darwin presented his stunning insights a landmark book that forever altered the way human beings view themselves and the world they live in. In The Origin of Species, he convincingly demonstrates the fact of evolution: that existing animals and plants cannot have appeared separately but must have slowly transformed from ancestral creatures. Most important, the book fully explains the mechanism that effects such a transformation: natural selection, the idea that made evolution scientifically intelligible for the first time.One of the few revolutionary works of science that is engrossingly readable, The Origin of Species not only launched the science of modern biology but also has influenced virtually all subsequent literary, philosophical, and religious thinking.George Levine, Kenneth Burke Professor of English Literature at Rutgers University, has written extensively about Darwin and the relation of science and literature, particularly in Darwin and the Novelists. He is the author of many related books, including The Realistic Imagination, Dying to Know, and his birdwatching memoirs, Lifebirds.

@article{doi1023072485224,
    author = "Livezey, R. L. and Darwin, Charles",
    title = "On the Origin of Species by Means of Natural Selection",
    year = "1953",
    journal = "The American Midland Naturalist",
    abstract = "The Origin of Species, by Charles Darwin, is part of the Barnes \& Noble Classicsseries, which offers quality editions at affordable prices to the student and the general reader, including new scholarship, thoughtful design, and pages of carefully crafted extras. Here are some of the remarkable features of Barnes \& Noble New introductions commissioned from today's top writers and scholars Biographies of the authors Chronologies of contemporary historical, biographical, and cultural events Footnotes and endnotes Selective discussions of imitations, parodies, poems, books, plays, paintings, operas, statuary, and films inspired by the work Comments by other famous authors Study questions to challenge the reader's viewpoints and expectations Bibliographies for further reading Indices \& Glossaries, when appropriate All editions are beautifully designed and are printed to superior specifications; some include illustrations of historical interest. Barnes \& Noble Classics pulls together a constellation of influencesbiographical, historical, and literaryto enrich each reader's understanding of these enduring works.On December 27, 1831, the young naturalist Charles Darwin left Plymouth Harbor aboard the HMS Beagle. For the next five years, he conducted research on plants and animals from around the globe, amassing a body of evidence that would culminate one of the greatest discoveries the history of mankindthe theory of evolution.Darwin presented his stunning insights a landmark book that forever altered the way human beings view themselves and the world they live in. In The Origin of Species, he convincingly demonstrates the fact of evolution: that existing animals and plants cannot have appeared separately but must have slowly transformed from ancestral creatures. Most important, the book fully explains the mechanism that effects such a transformation: natural selection, the idea that made evolution scientifically intelligible for the first time.One of the few revolutionary works of science that is engrossingly readable, The Origin of Species not only launched the science of modern biology but also has influenced virtually all subsequent literary, philosophical, and religious thinking.George Levine, Kenneth Burke Professor of English Literature at Rutgers University, has written extensively about Darwin and the relation of science and literature, particularly in Darwin and the Novelists. He is the author of many related books, including The Realistic Imagination, Dying to Know, and his birdwatching memoirs, Lifebirds.",
    url = "https://doi.org/10.2307/2485224",
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Journal Article NATURAL SELECTION OF INDIVIDUALLY HARMFUL SOCIAL ADAPTATIONS AMONG SIBS WITH SPECIAL REFERENCE TO SOCIAL INSECTS Get access George C. Williams, George C. Williams Department of Natural Science Michigan State University Search for other works by this author on: Oxford Academic Google Scholar Doris C. Williams Doris C. Williams Department of Natural Science Michigan State University Search for other works by this author on: Oxford Academic Google Scholar Evolution, Volume 11, Issue 1, 1 March 1957, Pages 32–39, https://doi.org/10.1111/j.1558-5646.1957.tb02873.x Published: 01 March 1957 Article history Received: 24 May 1956 Published: 01 March 1957

@article{doi101111j155856461957tb02873x,
    author = "Williams, George C. and Williams, Doris C.",
    title = "NATURAL SELECTION OF INDIVIDUALLY HARMFUL SOCIAL ADAPTATIONS AMONG SIBS WITH SPECIAL REFERENCE TO SOCIAL INSECTS",
    year = "1957",
    journal = "Evolution",
    abstract = "Journal Article NATURAL SELECTION OF INDIVIDUALLY HARMFUL SOCIAL ADAPTATIONS AMONG SIBS WITH SPECIAL REFERENCE TO SOCIAL INSECTS Get access George C. Williams, George C. Williams Department of Natural Science Michigan State University Search for other works by this author on: Oxford Academic Google Scholar Doris C. Williams Doris C. Williams Department of Natural Science Michigan State University Search for other works by this author on: Oxford Academic Google Scholar Evolution, Volume 11, Issue 1, 1 March 1957, Pages 32–39, https://doi.org/10.1111/j.1558-5646.1957.tb02873.x Published: 01 March 1957 Article history Received: 24 May 1956 Published: 01 March 1957",
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This landmark theory of interpersonal relations and group functioning argues that the starting point for understanding social behavior is the analysis of dyadic interdependence. Such an analysis portrays the ways in which the separate and joint actions of two persons affect the quality of their lives and the survival of their relationship. The authors focus on patterns of interdependence, and on the assumption that these patterns play an important causal role in the processes, roles, and norms of relationships. This powerful theory has many applications in all the social sciences, including the study of social and moral norms; close-pair relationships; conflicts of interest and cognitive disputes; social orientations; the social evolution of economic prosperity and leadership in groups; and personal relationships.

@article{doi1023073709294,
    author = "Kenkel, William F. and Thibaut, John and Kelley, Harold H.",
    title = "The Social Psychology of Groups",
    year = "1959",
    journal = "The American Catholic Sociological Review",
    abstract = "This landmark theory of interpersonal relations and group functioning argues that the starting point for understanding social behavior is the analysis of dyadic interdependence. Such an analysis portrays the ways in which the separate and joint actions of two persons affect the quality of their lives and the survival of their relationship. The authors focus on patterns of interdependence, and on the assumption that these patterns play an important causal role in the processes, roles, and norms of relationships. This powerful theory has many applications in all the social sciences, including the study of social and moral norms; close-pair relationships; conflicts of interest and cognitive disputes; social orientations; the social evolution of economic prosperity and leadership in groups; and personal relationships.",
    url = "https://doi.org/10.2307/3709294",
    doi = "10.2307/3709294",
    openalex = "W1654874180"
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@article{doi101038200623a0,
    author = "Wynne‐Edwards, V. C.",
    title = "Intergroup Selection in the Evolution of Social Systems",
    year = "1963",
    journal = "Nature",
    url = "https://doi.org/10.1038/200623a0",
    doi = "10.1038/200623a0",
    openalex = "W1975600279"
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@article{doi1010382281218a0,
    author = "Hamilton, W D",
    title = "Selfish and Spiteful Behaviour in an Evolutionary Model",
    year = "1970",
    journal = "Nature",
    url = "https://doi.org/10.1038/2281218a0",
    doi = "10.1038/2281218a0",
    openalex = "W2144228882"
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@inproceedings{darlington1971nonmathematical1,
    author = "Darlington, P. J",
    title = "Nonmathematical models for evolution of altruism and for group selection",
    year = "1971",
    booktitle = "Proceedings of the National Academy of Sciences, v. 69, p. 293-297",
    note = "talkorigins\_source = {true}; raw\_reference = {Darlington, P. J., 1971, Nonmathematical models for evolution of altruism and for group selection: Proceedings of the National Academy of Sciences, v. 69, p. 293-297.}"
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A model is presented to account for the natural selection of what is termed reciprocally altruistic behavior. The model shows how selection can operate against the cheater (non-reciprocator) in the system. Three instances of altruistic behavior are discussed, the evolution of which the model can explain: (1) behavior involved in cleaning symbioses; (2) warning cries in birds; and (3) human reciprocal altruism. Regarding human reciprocal altruism, it is shown that the details of the psychological system that regulates this altruism can be explained by the model. Specifically, friendship, dislike, moralistic aggression, gratitude, sympathy, trust, suspicion, trustworthiness, aspects of guilt, and some forms of dishonesty and hypocrisy can be explained as important adaptations to regulate the altruistic system. Each individual human is seen as possessing altruistic and cheating tendencies, the expression of which is sensitive to developmental variables that were selected to set the tendencies at a balance appropriate to the local social and ecological environment.

@article{doi101086406755,
    author = "Trivers, Robert",
    title = "The Evolution of Reciprocal Altruism",
    year = "1971",
    journal = "The Quarterly Review of Biology",
    abstract = "A model is presented to account for the natural selection of what is termed reciprocally altruistic behavior. The model shows how selection can operate against the cheater (non-reciprocator) in the system. Three instances of altruistic behavior are discussed, the evolution of which the model can explain: (1) behavior involved in cleaning symbioses; (2) warning cries in birds; and (3) human reciprocal altruism. Regarding human reciprocal altruism, it is shown that the details of the psychological system that regulates this altruism can be explained by the model. Specifically, friendship, dislike, moralistic aggression, gratitude, sympathy, trust, suspicion, trustworthiness, aspects of guilt, and some forms of dishonesty and hypocrisy can be explained as important adaptations to regulate the altruistic system. Each individual human is seen as possessing altruistic and cheating tendencies, the expression of which is sensitive to developmental variables that were selected to set the tendencies at a balance appropriate to the local social and ecological environment.",
    url = "https://doi.org/10.1086/406755",
    doi = "10.1086/406755",
    openalex = "W2167030552",
    references = "doi101111j1474919x1962tb08690x, doi101177002200275800200401, doi101201b186533, doi1015159781400820108, doi101537ase188722495, doi1023071375039, doi1023072092623, doi105962bhltitle27468, openalexw1997302797, openalexw2151993477, openalexw2304361434, openalexw2330340155"
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Living things are constantly engaged in a struggle for existence, and ingenious devices for the purpose of self-preservation can be seen in all types of animal and plant life. However, nature also displays phenomena that are not related to survival or that seem clearly to violate the principle of self-preservation - particularly when organisms interact with one another. Darwin investigated these apparent contradictions and proposed that both mechanisms of self preservation and those of reproduction are explained by a more basic principle of natural - the reproductive survival of the fittest. George C. Williams in Group Selection challenges the adequacy of this process of selection at the individual level.Williams has here collected the work of the chief partisans with opposed viewpoints on the theory of selection at the group level to state their arguments and rebuttals. A minority of modern biologists offer evidence to show that groups of living things are organized to assure their collective survival; they are not merely collections of individuals designed for their own survival and reproduction. In opposition, defenders of the traditional point of view charge that mechanisms of group survival are based on illusion and misinterpretation.Because of the wide range of opinion expressed in Group Selection, the reader is exposed to all sides of the dispute and encouraged to form his or her own views. In addition, as a source book on current evolutionary issues or for research or reference material, Group Selection remains a valuable addition to every personal and institutional library in the biological sciences.

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    author = "Williams, George",
    title = "Group Selection",
    year = "1971",
    abstract = "Living things are constantly engaged in a struggle for existence, and ingenious devices for the purpose of self-preservation can be seen in all types of animal and plant life. However, nature also displays phenomena that are not related to survival or that seem clearly to violate the principle of self-preservation - particularly when organisms interact with one another. Darwin investigated these apparent contradictions and proposed that both mechanisms of self preservation and those of reproduction are explained by a more basic principle of natural - the reproductive survival of the fittest. George C. Williams in Group Selection challenges the adequacy of this process of selection at the individual level.Williams has here collected the work of the chief partisans with opposed viewpoints on the theory of selection at the group level to state their arguments and rebuttals. A minority of modern biologists offer evidence to show that groups of living things are organized to assure their collective survival; they are not merely collections of individuals designed for their own survival and reproduction. In opposition, defenders of the traditional point of view charge that mechanisms of group survival are based on illusion and misinterpretation.Because of the wide range of opinion expressed in Group Selection, the reader is exposed to all sides of the dispute and encouraged to form his or her own views. In addition, as a source book on current evolutionary issues or for research or reference material, Group Selection remains a valuable addition to every personal and institutional library in the biological sciences.",
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Mathematical biologists have failed to produce a satisfactory general model for evolution of altruism, i.e., of behaviors by which “altruists” benefit other individuals but not themselves; kin selection does not seem to be a sufficient explanation of nonreciprocal altruism. Nonmathematical (but mathematically acceptable) models are now proposed for evolution of negative altruism in dual-determinant and of positive altruism in tri-determinant systems. Peck orders, territorial systems, and an ant society are analyzed as examples. In all models, evolution is primarily by individual selection, probably supplemented by group selection. Group selection is differential extinction of populations. It can act only on populations preformed by selection at the individual level, but can either cancel individual selective trends (effecting evolutionary homeostasis) or supplement them; its supplementary effect is probably increasingly important in the evolution of increasingly organized populations.

@article{darlington1972nonmathematical,
    author = "Darlington, P. J.",
    title = "Nonmathematical Models for Evolution of Altruism, and for Group Selection",
    year = "1972",
    journal = "Proceedings of the National Academy of Sciences",
    abstract = "Mathematical biologists have failed to produce a satisfactory general model for evolution of altruism, i.e., of behaviors by which “altruists” benefit other individuals but not themselves; kin selection does not seem to be a sufficient explanation of nonreciprocal altruism. Nonmathematical (but mathematically acceptable) models are now proposed for evolution of negative altruism in dual-determinant and of positive altruism in tri-determinant systems. Peck orders, territorial systems, and an ant society are analyzed as examples. In all models, evolution is primarily by individual selection, probably supplemented by group selection. Group selection is differential extinction of populations. It can act only on populations preformed by selection at the individual level, but can either cancel individual selective trends (effecting evolutionary homeostasis) or supplement them; its supplementary effect is probably increasingly important in the evolution of increasingly organized populations.",
    url = "https://doi.org/10.1073/pnas.69.2.293",
    doi = "10.1073/pnas.69.2.293",
    number = "2",
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    pages = "293-297",
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    references = "doi101038218525a0, doi101073pnas6861254, openalexw2414076348"
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Mathematical biologists have failed to produce a satisfactory general model for evolution of altruism, i.e., of behaviors by which "altruists" benefit other individuals but not themselves; kin selection does not seem to be a sufficient explanation of nonreciprocal altruism. Nonmathematical (but mathematically acceptable) models are now proposed for evolution of negative altruism in dual-determinant and of positive altruism in tri-determinant systems. Peck orders, territorial systems, and an ant society are analyzed as examples. In all models, evolution is primarily by individual selection, probably supplemented by group selection. Group selection is differential extinction of populations. It can act only on populations preformed by selection at the individual level, but can either cancel individual selective trends (effecting evolutionary homeostasis) or supplement them; its supplementary effect is probably increasingly important in the evolution of increasingly organized populations.

@article{doi101073pnas692293,
    author = "Darlington, P. J.",
    title = "Nonmathematical Models for Evolution of Altruism, and for Group Selection",
    year = "1972",
    journal = "Proceedings of the National Academy of Sciences",
    abstract = {Mathematical biologists have failed to produce a satisfactory general model for evolution of altruism, i.e., of behaviors by which "altruists" benefit other individuals but not themselves; kin selection does not seem to be a sufficient explanation of nonreciprocal altruism. Nonmathematical (but mathematically acceptable) models are now proposed for evolution of negative altruism in dual-determinant and of positive altruism in tri-determinant systems. Peck orders, territorial systems, and an ant society are analyzed as examples. In all models, evolution is primarily by individual selection, probably supplemented by group selection. Group selection is differential extinction of populations. It can act only on populations preformed by selection at the individual level, but can either cancel individual selective trends (effecting evolutionary homeostasis) or supplement them; its supplementary effect is probably increasingly important in the evolution of increasingly organized populations.},
    url = "https://doi.org/10.1073/pnas.69.2.293",
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    openalex = "W2037812923",
    references = "doi101038218525a0, doi101073pnas6861254, openalexw2414076348"
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The place of mathematics in hypotheticodeductive processes and in biological research is discussed. (Natural) Selection is defined and described as differential elimination of performed sets at any level. Sets and acting sets are groups of units (themselves sets of smaller units) at any level that may or do interact. A pseudomathematical equation describes directional change (evolution) in sets at any level. Selection is the ram of evolution; it cannot generate, but can only direct, evolutionary energy. The energy of evolution is derived from molecular or chemical levels, is transmitted upwards through the increasingly complex sets of sets that form living systems, and is turned in directions determined by the sum of selective processes, at different levels, which may either supplement or oppose each other. All evolutionary processes conform to the pseudomathematical equation referred to above, use energy as described above, and have a P/OE (ratio of programming to open-endedness) that cannot be measured, but can be related to other P/OE values. Phylogeny and ontogeny are compared as processes af directional change with set selection. Stages in the evolution of multi-cellular individuals are suggested, and are essentially the same as stages in the evolution of some multi-individual insect societies. Thinking is considered as a part of ontogeny involving an irreversible, nonrepetitive process of set selection in the brain.

@article{doi101073pnas6951239,
    author = "Darlington, P. J.",
    title = "Nonmathematical Concepts of Selection, Evolutionary Energy, and Levels of Evolution",
    year = "1972",
    journal = "Proceedings of the National Academy of Sciences",
    abstract = "The place of mathematics in hypotheticodeductive processes and in biological research is discussed. (Natural) Selection is defined and described as differential elimination of performed sets at any level. Sets and acting sets are groups of units (themselves sets of smaller units) at any level that may or do interact. A pseudomathematical equation describes directional change (evolution) in sets at any level. Selection is the ram of evolution; it cannot generate, but can only direct, evolutionary energy. The energy of evolution is derived from molecular or chemical levels, is transmitted upwards through the increasingly complex sets of sets that form living systems, and is turned in directions determined by the sum of selective processes, at different levels, which may either supplement or oppose each other. All evolutionary processes conform to the pseudomathematical equation referred to above, use energy as described above, and have a P/OE (ratio of programming to open-endedness) that cannot be measured, but can be related to other P/OE values. Phylogeny and ontogeny are compared as processes af directional change with set selection. Stages in the evolution of multi-cellular individuals are suggested, and are essentially the same as stages in the evolution of some multi-individual insect societies. Thinking is considered as a part of ontogeny involving an irreversible, nonrepetitive process of set selection in the brain.",
    url = "https://doi.org/10.1073/pnas.69.5.1239",
    doi = "10.1073/pnas.69.5.1239",
    openalex = "W2043292425",
    references = "darlington1972nonmathematical, doi101001jama195103670280091044, doi101001jama197103180390056032, doi101016c20130124336, doi101073pnas6861254, doi101073pnas692293, doi101126science1443619718a, doi1023072406953, doi1043249780203706299, openalexw400267313"
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Man is more similar to the social insects than to the wolf and chimpanzee in complex social coordination, division of labor, and self‐sacrificial altruism. In the social insects, the behavioral dispositions involved are genetically determined, an evolution made possible by the absence of genetic competition among the cooperators. In man, genetic competition precludes the evolution of such genetic altruism. The behavioral dispositions which produce complex social interdependence and self‐sacrificial altruism must instead be products of culturally evolved indoctrination, which has had to counter self‐serving genetic tendencies. Thus unlike the social insect, man — as Freud noted — is profoundly ambivalent in his social role.

@article{doi101111j154045601972tb00030x,
    author = "Campbell, Donald T.",
    title = "On the Genetics of Altruism and the Counter‐Hedonic Components in Human Culture 1",
    year = "1972",
    journal = "Journal of Social Issues",
    abstract = "Man is more similar to the social insects than to the wolf and chimpanzee in complex social coordination, division of labor, and self‐sacrificial altruism. In the social insects, the behavioral dispositions involved are genetically determined, an evolution made possible by the absence of genetic competition among the cooperators. In man, genetic competition precludes the evolution of such genetic altruism. The behavioral dispositions which produce complex social interdependence and self‐sacrificial altruism must instead be products of culturally evolved indoctrination, which has had to counter self‐serving genetic tendencies. Thus unlike the social insect, man — as Freud noted — is profoundly ambivalent in his social role.",
    url = "https://doi.org/10.1111/j.1540-4560.1972.tb00030.x",
    doi = "10.1111/j.1540-4560.1972.tb00030.x",
    openalex = "W2075701917"
}

Species distribution models (SDMs) are numerical tools that combine observations of species occurrence or abundance with environmental estimates. They are used to gain ecological and evolutionary insights and to predict distributions across landscapes,...Read More

@article{doi101146annureves03110172001205,
    author = "Hamilton, W D",
    title = "Altruism and Related Phenomena, Mainly in Social Insects",
    year = "1972",
    journal = "Annual Review of Ecology and Systematics",
    abstract = "Species distribution models (SDMs) are numerical tools that combine observations of species occurrence or abundance with environmental estimates. They are used to gain ecological and evolutionary insights and to predict distributions across landscapes,...Read More",
    url = "https://doi.org/10.1146/annurev.es.03.110172.001205",
    doi = "10.1146/annurev.es.03.110172.001205",
    openalex = "W2014592456",
    references = "openalexw2616504082"
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Evolution of altruism by group selection involves sacrifice of some individuals, not to the "group as a whole," but to other individuals in the group. Deme-group selection may establish strictly altruistic genes in a population, but only under limited conditions, and perhaps never among vertebrates, among which apparently altruistic behaviors may always potentially benefit the altruists. Responsive-group selection is a more effective mode of evolution of altruism, conspicuous in man. Evolutionary reinforcement increases the force of selection of advantageous behaviors, including altruistic ones, by making them pleasant or rewarding. It is probably involved also in ecological habitat selection, and may be the source of many human emotions, including esthetic ones. Throwing (of stones and weapons) exemplifies both the possible importance of a difficult-to-measure evolutionary factor and the role of reinforcement; in human evolution throwing may have been decisive in food-getting and fighting, in shifting emphasis from brute force to skill, and in inducing evolution of a brain able to handle three-body geometric problems precisely and thus preadapted for more complex functions.

@article{darlington1975group,
    author = "Darlington, P J",
    title = "Group selection, altruism, reinforcement, and throwing in human evolution.",
    year = "1975",
    journal = "Proceedings of the National Academy of Sciences",
    abstract = {Evolution of altruism by group selection involves sacrifice of some individuals, not to the "group as a whole," but to other individuals in the group. Deme-group selection may establish strictly altruistic genes in a population, but only under limited conditions, and perhaps never among vertebrates, among which apparently altruistic behaviors may always potentially benefit the altruists. Responsive-group selection is a more effective mode of evolution of altruism, conspicuous in man. Evolutionary reinforcement increases the force of selection of advantageous behaviors, including altruistic ones, by making them pleasant or rewarding. It is probably involved also in ecological habitat selection, and may be the source of many human emotions, including esthetic ones. Throwing (of stones and weapons) exemplifies both the possible importance of a difficult-to-measure evolutionary factor and the role of reinforcement; in human evolution throwing may have been decisive in food-getting and fighting, in shifting emphasis from brute force to skill, and in inducing evolution of a brain able to handle three-body geometric problems precisely and thus preadapted for more complex functions.},
    url = "https://doi.org/10.1073/pnas.72.9.3748",
    doi = "10.1073/pnas.72.9.3748",
    number = "9",
    openalex = "W1966138547",
    pages = "3748-3752",
    volume = "72",
    references = "darlington1972nonmathematical, doi101038251410a0, doi101038scientificamerican096062, doi101073pnas6951239, doi101073pnas721143, doi101086406755, doi101126science17139771262, doi1023071376223, doi1023072799427, doi1023072800701, doi1023074086942, openalexw1489751887"
}

@article{doi101007bf02984178,
    author = "Scudo, Francesco M. and Ghiselin, Michael T.",
    title = "Familial selection and the evolution of social behavior",
    year = "1975",
    journal = "Journal of Genetics",
    url = "https://doi.org/10.1007/bf02984178",
    doi = "10.1007/bf02984178",
    openalex = "W2037836748",
    references = "doi101073pnas6861254"
}

@incollection{doi101016s0065260108603585,
    author = "Schwartz, Shalom H.",
    title = "Normative Influences on Altruism",
    year = "1977",
    booktitle = "Advances in experimental social psychology",
    url = "https://doi.org/10.1016/s0065-2601(08)60358-5",
    doi = "10.1016/s0065-2601(08)60358-5",
    openalex = "W2198829320",
    references = "doi101086406755, doi101111j154045601969tb00619x, doi1023071420595, doi1023071420824, doi1023072063068, doi1023072089106, doi1023072092246, doi1023072092889, doi1023072576242, openalexw1949366217, openalexw2032719376"
}

Data are presented which indicate a high frequency of concurrent multiple paternity in the progeny of females in a natural population of Drosophila pseudoobscura. A probability model is presented and used to obtain maximum-likelihood estimates of parameters describing the pattern of sperm use and the amount of concurrent multiple paternity in several population samples. The probability that two randomly selected offspring from a single randomly selected female have the same father was found to be.79. Estimates of effective mating frequency of male genotypes suggest that one of the samples came from a population in which there was nonrandom mating. Some evolutionary consequences of multiple matings in Drosophila are discussed.

@article{doi101086283197,
    author = "Cobbs, Gary",
    title = "Multiple Insemination and Male Sexual Selection in Natural Populations of Drosophila pseudoobscura",
    year = "1977",
    journal = "The American Naturalist",
    abstract = "Data are presented which indicate a high frequency of concurrent multiple paternity in the progeny of females in a natural population of Drosophila pseudoobscura. A probability model is presented and used to obtain maximum-likelihood estimates of parameters describing the pattern of sperm use and the amount of concurrent multiple paternity in several population samples. The probability that two randomly selected offspring from a single randomly selected female have the same father was found to be.79. Estimates of effective mating frequency of male genotypes suggest that one of the samples came from a population in which there was nonrandom mating. Some evolutionary consequences of multiple matings in Drosophila are discussed.",
    url = "https://doi.org/10.1086/283197",
    doi = "10.1086/283197",
    openalex = "W2085077755",
    references = "doi101086282886"
}

(Uploaded by Plazi for the Bat Literature Project) No abstract provided.

@article{doi101126science327542,
    author = "Emlen, Stephen T. and Oring, Lewis W.",
    title = "Ecology, Sexual Selection, and the Evolution of Mating Systems",
    year = "1977",
    journal = "Science",
    abstract = "(Uploaded by Plazi for the Bat Literature Project) No abstract provided.",
    url = "https://doi.org/10.1126/science.327542",
    doi = "10.1126/science.327542",
    openalex = "W1977320179",
    references = "doi1010160003347273900043, doi1010160022519364900384, doi1010160022519364900396, doi101086406755, doi101093icb141249, doi101126science1563774477, doi101146annureves05110174001545, doi101163156853974x00345, doi1015159780691185507, doi101537ase188722495, doi1023072874, doi105962bhltitle27468"
}

@incollection{armstrong1978altruism,
    author = "ARMSTRONG, RICHARD D.",
    title = "Altruism, Group Selection, Human Evolution",
    year = "1978",
    booktitle = "Evolutionary Models and Studies in Human Diversity",
    url = "https://doi.org/10.1515/9783110800043.39",
    doi = "10.1515/9783110800043.39",
    openalex = "W2480302470",
    pages = "39-46"
}

Altruism is a group phenomenon in which some genes or individuals, which must be presumed to be selfish, benefit others at cost to themselves. The presumption of selfishness and the fact of altruism are reconciled by kin-group selection and by reciprocal altruism. Kin-group selection is clearly visible only in special cases; its role even among social insects may be overestimated; it is probably usually inhibited by competition. However, reciprocal altruism is ubiquitous. All altruism is: (i) potentially reciprocal; (ii) potentially profitable to altruists as well as to recipients; (iii) environmentally determined, usually by position of individuals in group or environmental situations; and (iv) a net-gain lottery. These generalizations are illustrated by four idealized cases; the difficulty of applying them to real cases is illustrated by alarm-calling in groups of birds. Although altruism is a group phenomenon, it evolves by individual selection, by processes equivalent to co-evolutions. Its evolution is: (i) opposed by competition; (ii) costly, complex, and slow, and tending to produce an imprecise flexible altruism rather than a precisely detailed one; and (iii) supplemented by group selection (differential extinction of groups). That altruism in human beings conforms to these generalizations is a good working hypothesis. However, analysis does not "take the altruism out of (human) altruism." Humans do not calculate it, but behave altruistically because they have human altruistic emotions.

@article{doi101073pnas751385,
    author = "Darlington, P. J.",
    title = "Altruism: Its characteristics and evolution",
    year = "1978",
    journal = "Proceedings of the National Academy of Sciences",
    abstract = {Altruism is a group phenomenon in which some genes or individuals, which must be presumed to be selfish, benefit others at cost to themselves. The presumption of selfishness and the fact of altruism are reconciled by kin-group selection and by reciprocal altruism. Kin-group selection is clearly visible only in special cases; its role even among social insects may be overestimated; it is probably usually inhibited by competition. However, reciprocal altruism is ubiquitous. All altruism is: (i) potentially reciprocal; (ii) potentially profitable to altruists as well as to recipients; (iii) environmentally determined, usually by position of individuals in group or environmental situations; and (iv) a net-gain lottery. These generalizations are illustrated by four idealized cases; the difficulty of applying them to real cases is illustrated by alarm-calling in groups of birds. Although altruism is a group phenomenon, it evolves by individual selection, by processes equivalent to co-evolutions. Its evolution is: (i) opposed by competition; (ii) costly, complex, and slow, and tending to produce an imprecise flexible altruism rather than a precisely detailed one; and (iii) supplemented by group selection (differential extinction of groups). That altruism in human beings conforms to these generalizations is a good working hypothesis. However, analysis does not "take the altruism out of (human) altruism." Humans do not calculate it, but behave altruistically because they have human altruistic emotions.},
    url = "https://doi.org/10.1073/pnas.75.1.385",
    doi = "10.1073/pnas.75.1.385",
    openalex = "W1966263378",
    references = "darlington1972nonmathematical, darlington1975group, doi101002j0022033719774110tb01133x, doi101073pnas69113151, doi101073pnas692293, doi101073pnas6951239, doi101073pnas7441647, doi101126science1954280773, doi101126science19743101246, doi1023072063069, openalexw1585956443"
}

Group selection is defined as that process of genetic change which is caused by the differential extinction or proliferation of groups of organisms. A very large proportion of the literature pertaining to group selection consists of theoretical papers; the genetic problems of group selection have been addressed from many different mathematical viewpoints. The general conclusion has been that, although group selection is possible, it cannot override the effects of individual selection within populations except for a highly restricted set of parameter values. Since it is unlikely that conditions in natural populations would fall within the bounds imposed by the models, group selection, by and large, has been considered an insignificant force for evolutionary change. These theoretical conclusions and the assumptions from which they have been derived are reexamined in the light of recent empirical studies of group selection with laboratory populations of the flour beetle, Tribolium (Wade, 1976, 1977). It is shown that the models have a number of assumptions in common which are inherently unfavorable to the operation of group selection. Alternative assumptions derived from the empirical results are suggested and discussed in the hope that they will stimulate further theoretical and empirical study of this controversial subject.

@article{doi101086410450,
    author = "Wade, Michael J.",
    title = "A Critical Review of the Models of Group Selection",
    year = "1978",
    journal = "The Quarterly Review of Biology",
    abstract = "Group selection is defined as that process of genetic change which is caused by the differential extinction or proliferation of groups of organisms. A very large proportion of the literature pertaining to group selection consists of theoretical papers; the genetic problems of group selection have been addressed from many different mathematical viewpoints. The general conclusion has been that, although group selection is possible, it cannot override the effects of individual selection within populations except for a highly restricted set of parameter values. Since it is unlikely that conditions in natural populations would fall within the bounds imposed by the models, group selection, by and large, has been considered an insignificant force for evolutionary change. These theoretical conclusions and the assumptions from which they have been derived are reexamined in the light of recent empirical studies of group selection with laboratory populations of the flour beetle, Tribolium (Wade, 1976, 1977). It is shown that the models have a number of assumptions in common which are inherently unfavorable to the operation of group selection. Alternative assumptions derived from the empirical results are suggested and discussed in the hope that they will stimulate further theoretical and empirical study of this controversial subject.",
    url = "https://doi.org/10.1086/410450",
    doi = "10.1086/410450",
    openalex = "W2030152342"
}

1. Multi-female groups of primates fall into two main classes, (a) female-bonded (FB) and (b) non-female-bonded (non-FB). A model is presented to account for the evolution of FB groups in terms of ecological pressures on female relationships. 2. The model suggests that FB groups have evolved as a result of competition for high-quality food patches containing a limited number of feeding sites. Groups are viewed as being based on cooperative relationships among females. These relationships are beneficial because cooperators act together to supplant others from preferred food patches. 3. Ecological data support the model for most FB species, but not for Theropithecus gelada or Colobus guereza, whose foods are not found in high-quality patches with limited feeding sites. Non-FB species conform to expectation, either because they do not use high-quality patches, or because feeding competition has disruptive effects during periods of food scarcity. 4. The behaviour of females differs as expected between FB and non-FB species in group movements and in inter-group interactions; in both contexts females are more involved in FB species. 5. Multi-male groups tend to be found in non-territorial FB species. The presence of several males per group is suggested to benefit females by raising the competitive ability of the group in inter-group interactions. 6. Competitive relationships among females are more strongly marked in FB groups than in non-FB groups. The model suggests that relationships in most FB groups are ultimately related to feeding competition.

@article{doi101163156853980x00447,
    author = "Wrangham, Richard W.",
    title = "An Ecological Model of Female-Bonded Primate Groups",
    year = "1980",
    journal = "Behaviour",
    abstract = "1. Multi-female groups of primates fall into two main classes, (a) female-bonded (FB) and (b) non-female-bonded (non-FB). A model is presented to account for the evolution of FB groups in terms of ecological pressures on female relationships. 2. The model suggests that FB groups have evolved as a result of competition for high-quality food patches containing a limited number of feeding sites. Groups are viewed as being based on cooperative relationships among females. These relationships are beneficial because cooperators act together to supplant others from preferred food patches. 3. Ecological data support the model for most FB species, but not for Theropithecus gelada or Colobus guereza, whose foods are not found in high-quality patches with limited feeding sites. Non-FB species conform to expectation, either because they do not use high-quality patches, or because feeding competition has disruptive effects during periods of food scarcity. 4. The behaviour of females differs as expected between FB and non-FB species in group movements and in inter-group interactions; in both contexts females are more involved in FB species. 5. Multi-male groups tend to be found in non-territorial FB species. The presence of several males per group is suggested to benefit females by raising the competitive ability of the group in inter-group interactions. 6. Competitive relationships among females are more strongly marked in FB groups than in non-FB groups. The model suggests that relationships in most FB groups are ultimately related to feeding competition.",
    url = "https://doi.org/10.1163/156853980x00447",
    doi = "10.1163/156853980x00447",
    openalex = "W2032093172",
    references = "doi1010160022519374901118, doi1010160162309579900049, doi101016s0066185668800032, doi101086282907, doi101126science327542, openalexw2616504082"
}

The joint evolution of female mating preferences and secondary sexual characters of males is modeled for polygamous species in which males provide only genetic material to the next generation and females have many potential mates to choose among. Despite stabilizing natural selection on males, various types of mating preferences may create a runaway process in which the outcome of phenotypic evolution depends critically on the genetic variation parameters and initial conditions of a population. Even in the absence of genetic instability, rapid evolution can result from an interaction of natural and sexual selection with random genetic drift along lines of equilibria. The models elucidate genetic mechanisms that can initiate or contribute to rapid speciation by sexual isolation and divergence of secondary sexual characters.

@article{doi101073pnas7863721,
    author = "Lande, Russell",
    title = "Models of speciation by sexual selection on polygenic traits",
    year = "1981",
    journal = "Proceedings of the National Academy of Sciences",
    abstract = "The joint evolution of female mating preferences and secondary sexual characters of males is modeled for polygamous species in which males provide only genetic material to the next generation and females have many potential mates to choose among. Despite stabilizing natural selection on males, various types of mating preferences may create a runaway process in which the outcome of phenotypic evolution depends critically on the genetic variation parameters and initial conditions of a population. Even in the absence of genetic instability, rapid evolution can result from an interaction of natural and sexual selection with random genetic drift along lines of equilibria. The models elucidate genetic mechanisms that can initiate or contribute to rapid speciation by sexual isolation and divergence of secondary sexual characters.",
    url = "https://doi.org/10.1073/pnas.78.6.3721",
    doi = "10.1073/pnas.78.6.3721",
    openalex = "W2002652493",
    references = "doi101017s0016672300016037, doi1023072341823, doi105281zenodo10742832, doi105962bhltitle2112"
}

@article{doi101111j155856461982tb05003x,
    author = "Kirkpatrick, Mark",
    title = "SEXUAL SELECTION AND THE EVOLUTION OF FEMALE CHOICE",
    year = "1982",
    journal = "Evolution",
    url = "https://doi.org/10.1111/j.1558-5646.1982.tb05003.x",
    doi = "10.1111/j.1558-5646.1982.tb05003.x",
    openalex = "W2019598428",
    references = "doi101111j155856461980tb04817x, doi105962bhltitle2112"
}

Natural selection acts on phenotypes, regardless of their genetic basis, and produces immediate phenotypic effects within a generation that can be measured without recourse to principles of heredity or evolution. In contrast, evolutionary response to selection, the genetic change that occurs from one generation to the next, does depend on genetic variation. Animal and plant breeders routinely distinguish phenotypic selection from evolutionary response to selection (Mayo, 1980; Falconer, 1981). Upon making this critical distinction, emphasized by Haldane (1954), precise methods can be formulated for the measurement of phenotypic natural selection. Correlations between characters seriously complicate the measurement of phenotypic selection, because selection on a particular trait produces not only a direct effect on the distribution of that trait in a population, but also produces indirect effects on the distribution of correlated characters. The problem of character correlations has been largely ignored in current methods for measuring natural selection on quantitative traits. Selection has usually been treated as if it acted only on single characters (e.g., Haldane, 1954; Van Valen, 1965a; O'Donald, 1968, 1970; reviewed by Johnson, 1976 Ch. 7). This is obviously a tremendous oversimplification, since natural selection acts on many characters simultaneously and phenotypic correlations between traits are ubiquitous. In an important but neglected paper, Pearson (1903) showed that multivariate statistics could be used to disentangle the direct and indirect effects of selection to determine which traits in a correlated ensemble are the focus of direct selection. Here we extend and generalize Pearson's major results. The purpose of this paper is to derive measures of directional and stabilizing (or disruptive) selection on each of a set of phenotypically correlated characters. The analysis is retrospective, based on observed changes in the multivariate distribution of characters within a generation, not on the evolutionary response to selection. Nevertheless, the measures we propose have a close connection with equations for evolutionary change. Many other commonly used measures of the intensity of selection (such as selective mortality, change in mean fitness, variance in fitness, or estimates of particular forms of fitness functions) have little predictive value in relation to evolutionary change in quantitative traits. To demonstrate the utility of our approach, we analyze selection on four morphological characters in a population of pentatomid bugs during a brief period of high mortality. We also summarize a multivariate selection analysis on nine morphological characters of house sparrows caught in a severe winter storm, using the classic data of Bumpus (1899). Direct observations and measurements of natural selection serve to clarify one of the major factors of evolution. Critiques of the adaptationist program (Lewontin, 1978; Gould and Lewontin, 1979) stress that adaptation and selection are often invoked without strong supporting evidence. We suggest quantitative measurements of selection as the best alternative to the fabrication of adaptive scenarios. Our optimism that measurement can replace rhetorical claims for adaptation and selection is founded in the growing success of field workers in their efforts to measure major components of fitness in natural populations (e.g., Thornhill, 1976; Howard, 1979; Downhower and Brown, 1980; Boag and Grant, 1981; Clutton-Brock et

@article{doi101111j155856461983tb00236x,
    author = "Lande, Russell and Arnold, Stevan J.",
    title = "THE MEASUREMENT OF SELECTION ON CORRELATED CHARACTERS",
    year = "1983",
    journal = "Evolution",
    abstract = "Natural selection acts on phenotypes, regardless of their genetic basis, and produces immediate phenotypic effects within a generation that can be measured without recourse to principles of heredity or evolution. In contrast, evolutionary response to selection, the genetic change that occurs from one generation to the next, does depend on genetic variation. Animal and plant breeders routinely distinguish phenotypic selection from evolutionary response to selection (Mayo, 1980; Falconer, 1981). Upon making this critical distinction, emphasized by Haldane (1954), precise methods can be formulated for the measurement of phenotypic natural selection. Correlations between characters seriously complicate the measurement of phenotypic selection, because selection on a particular trait produces not only a direct effect on the distribution of that trait in a population, but also produces indirect effects on the distribution of correlated characters. The problem of character correlations has been largely ignored in current methods for measuring natural selection on quantitative traits. Selection has usually been treated as if it acted only on single characters (e.g., Haldane, 1954; Van Valen, 1965a; O'Donald, 1968, 1970; reviewed by Johnson, 1976 Ch. 7). This is obviously a tremendous oversimplification, since natural selection acts on many characters simultaneously and phenotypic correlations between traits are ubiquitous. In an important but neglected paper, Pearson (1903) showed that multivariate statistics could be used to disentangle the direct and indirect effects of selection to determine which traits in a correlated ensemble are the focus of direct selection. Here we extend and generalize Pearson's major results. The purpose of this paper is to derive measures of directional and stabilizing (or disruptive) selection on each of a set of phenotypically correlated characters. The analysis is retrospective, based on observed changes in the multivariate distribution of characters within a generation, not on the evolutionary response to selection. Nevertheless, the measures we propose have a close connection with equations for evolutionary change. Many other commonly used measures of the intensity of selection (such as selective mortality, change in mean fitness, variance in fitness, or estimates of particular forms of fitness functions) have little predictive value in relation to evolutionary change in quantitative traits. To demonstrate the utility of our approach, we analyze selection on four morphological characters in a population of pentatomid bugs during a brief period of high mortality. We also summarize a multivariate selection analysis on nine morphological characters of house sparrows caught in a severe winter storm, using the classic data of Bumpus (1899). Direct observations and measurements of natural selection serve to clarify one of the major factors of evolution. Critiques of the adaptationist program (Lewontin, 1978; Gould and Lewontin, 1979) stress that adaptation and selection are often invoked without strong supporting evidence. We suggest quantitative measurements of selection as the best alternative to the fabrication of adaptive scenarios. Our optimism that measurement can replace rhetorical claims for adaptation and selection is founded in the growing success of field workers in their efforts to measure major components of fitness in natural populations (e.g., Thornhill, 1976; Howard, 1979; Downhower and Brown, 1980; Boag and Grant, 1981; Clutton-Brock et",
    url = "https://doi.org/10.1111/j.1558-5646.1983.tb00236.x",
    doi = "10.1111/j.1558-5646.1983.tb00236.x",
    openalex = "W2322715144",
    references = "doi101038227520a0, doi101086404940, doi101093aesa383396, doi101093aibsbulletin2214b, doi101098rspb19790086, doi101111j146918091957tb01874x, doi101111j155856461979tb04694x, doi101890001296582006871445soefdd20co2, doi1023071435536, doi1023071439305, doi1023072344782, doi1023072529912, doi1023074471, doi105962bhltitle27468, doi107312simp93764"
}

The amounts of inbreeding depression upon selfing and of heterosis upon outcrossing determine the strength of selection on the selfing rate in a population when this evolves polygenically by small steps. Genetic models are constructed which allow inbreeding depression to change with the mean selfing rate in a population by incorporating both mutation to recessive and partially dominant lethal and sublethal alleles at many loci and mutation in quantitative characters under stabilizing selection. The models help to explain observations of high inbreeding depression (> 50%) upon selfing in primarily outcrossing populations, as well as considerable heterosis upon outcrossing in primarily selfing populations. Predominant selfing and predominant outcrossing are found to be alternative stable states of the mating system in most plant populations. Which of these stable states a species approaches depends on the history of its population structure and the magnitude of effect of genes influencing the selfing rate.

@article{doi101111j155856461985tb04077x,
    author = "Lande, Russell and Schemske, Douglas W.",
    title = "THE EVOLUTION OF SELF‐FERTILIZATION AND INBREEDING DEPRESSION IN PLANTS. I. GENETIC MODELS",
    year = "1985",
    journal = "Evolution",
    abstract = "The amounts of inbreeding depression upon selfing and of heterosis upon outcrossing determine the strength of selection on the selfing rate in a population when this evolves polygenically by small steps. Genetic models are constructed which allow inbreeding depression to change with the mean selfing rate in a population by incorporating both mutation to recessive and partially dominant lethal and sublethal alleles at many loci and mutation in quantitative characters under stabilizing selection. The models help to explain observations of high inbreeding depression (> 50\%) upon selfing in primarily outcrossing populations, as well as considerable heterosis upon outcrossing in primarily selfing populations. Predominant selfing and predominant outcrossing are found to be alternative stable states of the mating system in most plant populations. Which of these stable states a species approaches depends on the history of its population structure and the magnitude of effect of genes influencing the selfing rate.",
    url = "https://doi.org/10.1111/j.1558-5646.1985.tb04077.x",
    doi = "10.1111/j.1558-5646.1985.tb04077.x",
    openalex = "W2316973238",
    references = "doi101017s0016672300016037, doi101111j155856461983tb00236x, doi1023072407274"
}

@article{nunney1985group,
    author = "Nunney, Len",
    title = "Group Selection, Altruism, and Structured-Deme Models",
    year = "1985",
    journal = "The American Naturalist",
    url = "https://doi.org/10.1086/284410",
    doi = "10.1086/284410",
    number = "2",
    openalex = "W2018945684",
    pages = "212-230",
    volume = "126",
    references = "doi1010160022519364900384, doi101038227520a0, doi101038269578a0, doi101073pnas721143, doi101086410450, doi101093genetics16297, doi101111j1474919x1962tb08690x, doi1015159781400820108, doi105962bhltitle27468, openalexw1493831303"
}

Nature of presents a powerful analysis of the evolutionary concepts of natural selection, fitness, and adaptation. The book clarifies controversial issues concerning altruism, group selection, and the idea that organisms are survival machines built for the good of the genes that inhabit them. As the book unfolds, it provides a straightforward and self-contained introduction to philosophical and biological problems in evolutionary theory.In the first part, Evolutionary Theory as a Theory of Forces, Sober offers an illuminating characterization of the structure of evolutionary theory. Besides laying to rest the spurious charge that theory is vacuous and unscientific, Sober describes the role of chance in evolution and pinpoints the characteristic structure of evolutionary explanations.The book's second part, Group Above and the Gene Below: The Units of Selection Controversy, thoroughly explores the problem of the units of selection, superseding the author's earlier essays, which are widely regarded as the best available treatment of this problem.

@article{doi1023072185056,
    author = "Brandon, Robert N. and Sober, Elliott",
    title = "The Nature of Selection: Evolutionary Theory in Philosophical Focus.",
    year = "1986",
    journal = "The Philosophical Review",
    abstract = "Nature of presents a powerful analysis of the evolutionary concepts of natural selection, fitness, and adaptation. The book clarifies controversial issues concerning altruism, group selection, and the idea that organisms are survival machines built for the good of the genes that inhabit them. As the book unfolds, it provides a straightforward and self-contained introduction to philosophical and biological problems in evolutionary theory.In the first part, Evolutionary Theory as a Theory of Forces, Sober offers an illuminating characterization of the structure of evolutionary theory. Besides laying to rest the spurious charge that theory is vacuous and unscientific, Sober describes the role of chance in evolution and pinpoints the characteristic structure of evolutionary explanations.The book's second part, Group Above and the Gene Below: The Units of Selection Controversy, thoroughly explores the problem of the units of selection, superseding the author's earlier essays, which are widely regarded as the best available treatment of this problem.",
    url = "https://doi.org/10.2307/2185056",
    doi = "10.2307/2185056",
    openalex = "W1498210519"
}

Abstract Various systemic aspects of animal and human minds are explored. Formulation of a replicative evolutionary model of the mind is presented which is based upon the recognition of this entity as a component system. It can be demonstrated that interactions of neurons have replicative organization. It was concluded that intelligent activity of the animal brain manifest itself in producing and maintaining a kind of environmental model. The environmental model is a higher organization above the level of neurons, its basic functional units are called concepts. Each single concept consists of three parts: (1(cue; (2) referential‐structure; and (3) behavioral‐instructions. Interactions among the various concepts of the brain create a concept‐superstructure which behaves as a dynamic replicative component system in controlling animal and human actions. It is assumed that selection operating in the replicative process of concept making which acts as the main factor in creating ontogenetic variability of behavior. The essential process of learning is selection of concepts generated by the brain and in that way the construction of the evolutionary dynamic concept‐superstructures of the brain's environmental model.

@article{doi1010800260402719879972045,
    author = "Csånanyi, V.",
    title = "The replicative evolutionary model of animal and human minds",
    year = "1987",
    journal = "World Futures",
    abstract = "Abstract Various systemic aspects of animal and human minds are explored. Formulation of a replicative evolutionary model of the mind is presented which is based upon the recognition of this entity as a component system. It can be demonstrated that interactions of neurons have replicative organization. It was concluded that intelligent activity of the animal brain manifest itself in producing and maintaining a kind of environmental model. The environmental model is a higher organization above the level of neurons, its basic functional units are called concepts. Each single concept consists of three parts: (1(cue; (2) referential‐structure; and (3) behavioral‐instructions. Interactions among the various concepts of the brain create a concept‐superstructure which behaves as a dynamic replicative component system in controlling animal and human actions. It is assumed that selection operating in the replicative process of concept making which acts as the main factor in creating ontogenetic variability of behavior. The essential process of learning is selection of concepts generated by the brain and in that way the construction of the evolutionary dynamic concept‐superstructures of the brain's environmental model.",
    url = "https://doi.org/10.1080/02604027.1987.9972045",
    doi = "10.1080/02604027.1987.9972045",
    openalex = "W1965938887",
    references = "doi101073pnas6951239"
}

Journal Article Individual selection, kin selection, and the shifting balance in the evolution of warning colours: the evidence from butterflies Get access JAMES MALLET, JAMES MALLET 1Gallon Laboratory, Department of Genetics and Biometry, University College London, Wolfson House, 4 Stephenson Way, London NW1 2HE Search for other works by this author on: Oxford Academic Google Scholar MICHAEL C. SINGER MICHAEL C. SINGER 2Department of Zoology, University of Texas at Austin, Austin, Texas 78712, U.S.A. Search for other works by this author on: Oxford Academic Google Scholar Biological Journal of the Linnean Society, Volume 32, Issue 4, December 1987, Pages 337–350, https://doi.org/10.1111/j.1095-8312.1987.tb00435.x Published: 14 January 2008 Article history Received: 05 February 1986 Accepted: 10 July 1987 Published: 14 January 2008

@article{doi101111j109583121987tb00435x,
    author = "Mallet, James and Singer, Michael C.",
    title = "Individual selection, kin selection, and the shifting balance in the evolution of warning colours: the evidence from butterflies",
    year = "1987",
    journal = "Biological Journal of the Linnean Society",
    abstract = "Journal Article Individual selection, kin selection, and the shifting balance in the evolution of warning colours: the evidence from butterflies Get access JAMES MALLET, JAMES MALLET 1Gallon Laboratory, Department of Genetics and Biometry, University College London, Wolfson House, 4 Stephenson Way, London NW1 2HE Search for other works by this author on: Oxford Academic Google Scholar MICHAEL C. SINGER MICHAEL C. SINGER 2Department of Zoology, University of Texas at Austin, Austin, Texas 78712, U.S.A. Search for other works by this author on: Oxford Academic Google Scholar Biological Journal of the Linnean Society, Volume 32, Issue 4, December 1987, Pages 337–350, https://doi.org/10.1111/j.1095-8312.1987.tb00435.x Published: 14 January 2008 Article history Received: 05 February 1986 Accepted: 10 July 1987 Published: 14 January 2008",
    url = "https://doi.org/10.1111/j.1095-8312.1987.tb00435.x",
    doi = "10.1111/j.1095-8312.1987.tb00435.x",
    openalex = "W2103395895",
    references = "brower1964birds, doi10103712293000, doi101073pnas7863721, doi101126science188418319, doi101126science3576198, doi101537ase188722495, doi1023071437762, doi1023072063068, doi1023072576242, doi1023074510368, doi105962bhltitle27468, doi105962p203298, huheey1961studies, openalexw2624262714"
}

@article{doi101016s0022519388802194,
    author = "Boyd, Robert and Richerson, Peter J.",
    title = "The evolution of reciprocity in sizable groups",
    year = "1988",
    journal = "Journal of Theoretical Biology",
    url = "https://doi.org/10.1016/s0022-5193(88)80219-4",
    doi = "10.1016/s0022-5193(88)80219-4",
    openalex = "W2046307793",
    references = "doi101086410450, nunney1985group"
}

@article{doi101086261662,
    author = "Andreoni, James",
    title = "Giving with Impure Altruism: Applications to Charity and Ricardian Equivalence",
    year = "1989",
    journal = "Journal of Political Economy",
    url = "https://doi.org/10.1086/261662",
    doi = "10.1086/261662",
    openalex = "W1976429703",
    references = "doi1010160047272782900561, doi1010160047272786900241, doi1010160047272788900618, doi101086260266, doi101086261212, doi101086261341, doi101086261470, doi101086298126, doi1023071973663, doi1023072232704"
}

Abstract Many people have argued that the evolution of the human language faculty cannot be explained by Darwinian natural selection. Chomsky and Gould have suggested that language may have evolved as the by-product of selection for other abilities or as a consequence of as-yet unknown laws of growth and form. Others have argued that a biological specialization for grammar is incompatible with every tenet of Darwinian theory – that it shows no genetic variation, could not exist in any intermediate forms, confers no selective advantage, and would require more evolutionary time and genomic space than is available. We examine these arguments and show that they depend on inaccurate assumptions about biology or language or both. Evolutionary theory offers clear criteria for when a trait should be attributed to natural selection: complex design for some function, and the absence of alternative processes capable of explaining such complexity. Human language meets these criteria: Grammar is a complex mechanism tailored to the transmission of propositional structures through a serial interface. Autonomous and arbitrary grammatical phenomena have been offered as counterexamples to the position that language is an adaptation, but this reasoning is unsound: Communication protocols depend on arbitrary conventions that are adaptive as long as they are shared. Consequently, language acquisition in the child should systematically differ from language evolution in the species, and attempts to analogize them are misleading. Reviewing other arguments and data, we conclude that there is every reason to believe that a specialization for grammar evolved by a conventional neo-Darwinian process.

@article{doi101017s0140525x00081061,
    author = "Pinker, Steven and Bloom, Paul",
    title = "Natural language and natural selection",
    year = "1990",
    journal = "Behavioral and Brain Sciences",
    abstract = "Abstract Many people have argued that the evolution of the human language faculty cannot be explained by Darwinian natural selection. Chomsky and Gould have suggested that language may have evolved as the by-product of selection for other abilities or as a consequence of as-yet unknown laws of growth and form. Others have argued that a biological specialization for grammar is incompatible with every tenet of Darwinian theory – that it shows no genetic variation, could not exist in any intermediate forms, confers no selective advantage, and would require more evolutionary time and genomic space than is available. We examine these arguments and show that they depend on inaccurate assumptions about biology or language or both. Evolutionary theory offers clear criteria for when a trait should be attributed to natural selection: complex design for some function, and the absence of alternative processes capable of explaining such complexity. Human language meets these criteria: Grammar is a complex mechanism tailored to the transmission of propositional structures through a serial interface. Autonomous and arbitrary grammatical phenomena have been offered as counterexamples to the position that language is an adaptation, but this reasoning is unsound: Communication protocols depend on arbitrary conventions that are adaptive as long as they are shared. Consequently, language acquisition in the child should systematically differ from language evolution in the species, and attempts to analogize them are misleading. Reviewing other arguments and data, we conclude that there is every reason to believe that a specialization for grammar evolved by a conventional neo-Darwinian process.",
    url = "https://doi.org/10.1017/s0140525x00081061",
    doi = "10.1017/s0140525x00081061",
    openalex = "W2162471372",
    references = "caplan1983morality, doi1010160010027789900231, doi1010160022283668903926, doi1010160022519364900384, doi1010160162309589900137, doi101016s109051380100068x, doi101017s0094837300004310, doi101017s0094837300005224, doi101017s0140525x00047695, doi101017s0305004100015644, doi101038369716c0, doi101086276408, doi101086284064, doi101086406755, doi101098rspb19790086, doi101126science1090005, doi101126science6107993, doi101126science7455683, doi101126science7466396, doi101126science860134, doi101159000156428, doi1015159783110884166, doi1023071423235, doi1023072103745, doi1023072260026, doi1023072803365, doi1023073037993, doi102307414947, doi104159harvard9780674184404, doi105962bhltitle27468, doi107208chicago97802263088830010001, falk1983cerebral, openalexw1577806554, openalexw2171582839, openalexw2624262714, openalexw3038830718, openalexw3135630760"
}

@article{doi1023072234133,
    author = "Andreoni, James",
    title = "Impure Altruism and Donations to Public Goods: A Theory of Warm-Glow Giving",
    year = "1990",
    journal = "The Economic Journal",
    url = "https://doi.org/10.2307/2234133",
    doi = "10.2307/2234133",
    openalex = "W2111222789",
    references = "doi10100797803877279673, doi1010160047272782900561, doi1010160047272786900241, doi1010160047272788900618, doi101017cbo9781139174312, doi101086261212, doi101086261341, doi101086261662, doi1015159781400853564139, doi1023072091298, doi1023072232294, doi1023072232704, openalexw1512416168"
}

@article{doi101007bf00129882,
    author = "Sober, Elliott",
    title = "The evolution of altruism: Correlation, cost, and benefit",
    year = "1992",
    journal = "Biology \& Philosophy",
    url = "https://doi.org/10.1007/bf00129882",
    doi = "10.1007/bf00129882",
    openalex = "W2015293245",
    references = "doi1010160022519364900384, doi1010160169534789900372, doi101016s0022519389801699, doi101073pnas7941331, doi101086406755, doi101111j143903101979tb00682x, doi101126science7466396, doi1023072174952, doi102307257983, openalexw2624262714"
}

@article{doi101016016230959290032y,
    author = "Boyd, Robert and Richerson, Peter J.",
    title = "Punishment allows the evolution of cooperation (or anything else) in sizable groups",
    year = "1992",
    journal = "Ethology and Sociobiology",
    url = "https://doi.org/10.1016/0162-3095(92)90032-y",
    doi = "10.1016/0162-3095(92)90032-y",
    openalex = "W2147570389",
    references = "doi1023072063069, nunney1985group"
}

Abstract This important new volume in the Oxford Series in Ecology and Evolution examines the mechanism and action of natural selection in evolution. Williams offers his own synthesis of modern evolutionary theory -including discussions of the gene as the unit of selection, clade selection and macroevolution, diversity within and among populations, stasis, and other timely and provocative issues central to the study of evolution. Williams’ preeminent position in the field ensures immediate and widespread interest in the book among evolutionary biologists, geneticists, and their graduate students.

@book{doi101093oso97801950693270010001,
    author = "Williams, George C.",
    title = "Natural Selection: Domains, Levels and Challenges",
    year = "1992",
    abstract = "Abstract This important new volume in the Oxford Series in Ecology and Evolution examines the mechanism and action of natural selection in evolution. Williams offers his own synthesis of modern evolutionary theory -including discussions of the gene as the unit of selection, clade selection and macroevolution, diversity within and among populations, stasis, and other timely and provocative issues central to the study of evolution. Williams’ preeminent position in the field ensures immediate and widespread interest in the book among evolutionary biologists, geneticists, and their graduate students.",
    url = "https://doi.org/10.1093/oso/9780195069327.001.0001",
    doi = "10.1093/oso/9780195069327.001.0001",
    openalex = "W4388296129"
}

Two common features of biological communities are (a) complex interactions among species, which make community dynamics sensitive to initial conditions, and (b) spatial heterogeneity, which fragments large—scale ecological systems into a mosaic of patches, hereafter termed a "metacommunity." This computer simulation study examines the effect of complex interaction on the global and local dynamics of metacommunities. Patches are physically identical and differ only in the initial proportion of species that colonize the patches. The random variation is then magnified by deterministic interactions that cause patches to follow different trajectories based on initial conditions. After a period of interaction, individuals from all patches join in global pool of dispersers that colonize a new "generation" of patches. Complex interactions can have at least two important effects on metacommunity dynamics. First the number of species coexisting in the metacommunity can greatly exceed the number of species coexisting in any single patch, despite the fact that the patches are physically identical, the species do not differ in colonization ability, and stochastic effects are absent after the colonization stage. Second, complex interactions provide a new source of variation upon which natural selection can operate at the patch level, providing a mechanism for the evolution of functionally organized communities.

@article{doi1023071941449,
    author = "Wilson, David Sloan",
    title = "Complex Interactions in Metacommunities, with Implications for Biodiversity and Higher Levels of Selection",
    year = "1992",
    journal = "Ecology",
    abstract = {Two common features of biological communities are (a) complex interactions among species, which make community dynamics sensitive to initial conditions, and (b) spatial heterogeneity, which fragments large—scale ecological systems into a mosaic of patches, hereafter termed a "metacommunity." This computer simulation study examines the effect of complex interaction on the global and local dynamics of metacommunities. Patches are physically identical and differ only in the initial proportion of species that colonize the patches. The random variation is then magnified by deterministic interactions that cause patches to follow different trajectories based on initial conditions. After a period of interaction, individuals from all patches join in global pool of dispersers that colonize a new "generation" of patches. Complex interactions can have at least two important effects on metacommunity dynamics. First the number of species coexisting in the metacommunity can greatly exceed the number of species coexisting in any single patch, despite the fact that the patches are physically identical, the species do not differ in colonization ability, and stochastic effects are absent after the colonization stage. Second, complex interactions provide a new source of variation upon which natural selection can operate at the patch level, providing a mechanism for the evolution of functionally organized communities.},
    url = "https://doi.org/10.2307/1941449",
    doi = "10.2307/1941449",
    openalex = "W2158214141",
    references = "doi101016s0022519389801699, doi101086282114"
}

Contents: The Question Posed by Our Concern for Others: Altruism or Egoism? Part I: The Altruism Question in Western Thought.Egoism and Altruism in Western Philosophy. Egoism and Altruism in Early Psychology. The Altruism Question in Contemporary Psychology. Part II: Toward an Answer: The Empathy-Altruism Hypothesis.A Scientific Method for Addressing the Altruism Question. A Three- Path Model of Egoistic and Altruistic Motivation to Help: The Empathy-Altruism Hypothesis. Egoistic Alternatives to the Empathy- Altruism Hypothesis. Part III: Testing the Egoistic Alternatives to the Empathy- Altruism Hypothesis.Aversive-Arousal Reduction. Empathy- Specific Punishment. Empathy-Specific Reward. Part IV: Extensions.Other Possible Sources of Altruistic Motivation: The Altruistic Personality. Implications and Limitations of the Empathy-Altruism Hypothesis.

@article{doi105860choice294797,
    title = "The altruism question: toward a social-psychological answer",
    year = "1992",
    journal = "Choice Reviews Online",
    abstract = "Contents: The Question Posed by Our Concern for Others: Altruism or Egoism? Part I: The Altruism Question in Western Thought.Egoism and Altruism in Western Philosophy. Egoism and Altruism in Early Psychology. The Altruism Question in Contemporary Psychology. Part II: Toward an Answer: The Empathy-Altruism Hypothesis.A Scientific Method for Addressing the Altruism Question. A Three- Path Model of Egoistic and Altruistic Motivation to Help: The Empathy-Altruism Hypothesis. Egoistic Alternatives to the Empathy- Altruism Hypothesis. Part III: Testing the Egoistic Alternatives to the Empathy- Altruism Hypothesis.Aversive-Arousal Reduction. Empathy- Specific Punishment. Empathy-Specific Reward. Part IV: Extensions.Other Possible Sources of Altruistic Motivation: The Altruistic Personality. Implications and Limitations of the Empathy-Altruism Hypothesis.",
    url = "https://doi.org/10.5860/choice.29-4797",
    doi = "10.5860/choice.29-4797",
    openalex = "W2135370090"
}

@article{goodnight1992contextual,
    author = "Goodnight, Charles J. and Schwartz, James M. and Stevens, Lori",
    title = "Contextual Analysis of Models of Group Selection, Soft Selection, Hard Selection, and the Evolution of Altruism",
    year = "1992",
    journal = "The American Naturalist",
    url = "https://doi.org/10.1086/285438",
    doi = "10.1086/285438",
    number = "5",
    openalex = "W2006819253",
    pages = "743-761",
    volume = "140",
    references = "doi1010160022519364900384, doi101016s0022519389801699, doi1010382011145a0, doi101038227520a0, doi101073pnas721143, doi101111j146918091957tb01874x, doi101111j155856461983tb00236x, doi101111j155856461984tb00344x, doi1015159781400820108, doi1023072529912"
}

Abstract Group size covaries with relative neocortical volume in nonhuman primates. This regression equation predicts a group size for modern humans very similar to that for hunter-gatherer and traditional horticulturalist societies. Similar group sizes are found in other contemporary and historical societies. Nonhuman primates maintain group cohesion through social grooming; among the Old World monkeys and apes, social grooming time is linearly related to group size. Maintaining stability of human-sized groups by grooming alone would make intolerable time demands. It is therefore suggested (1) that the evolution of large groups in the human lineage depended on developing a more efficient method for time-sharing the processes of social bonding and (2) that language uniquely fulfills this requirement. Data on the size of conversational and other small interacting groups of humans accord with the predicted relative efficiency of conversation compared to grooming as a bonding process. In human conversations about 60% of time is spent gossiping about relationships and personal experiences. Language may accordingly have evolved to allow individuals to learn about the behavioural characteristics of other group members more rapidly than was feasible by direct observation alone.

@article{doi101017s0140525x00032325,
    author = "Dunbar, Robin",
    title = "Coevolution of neocortical size, group size and language in humans",
    year = "1993",
    journal = "Behavioral and Brain Sciences",
    abstract = "Abstract Group size covaries with relative neocortical volume in nonhuman primates. This regression equation predicts a group size for modern humans very similar to that for hunter-gatherer and traditional horticulturalist societies. Similar group sizes are found in other contemporary and historical societies. Nonhuman primates maintain group cohesion through social grooming; among the Old World monkeys and apes, social grooming time is linearly related to group size. Maintaining stability of human-sized groups by grooming alone would make intolerable time demands. It is therefore suggested (1) that the evolution of large groups in the human lineage depended on developing a more efficient method for time-sharing the processes of social bonding and (2) that language uniquely fulfills this requirement. Data on the size of conversational and other small interacting groups of humans accord with the predicted relative efficiency of conversation compared to grooming as a bonding process. In human conversations about 60\% of time is spent gossiping about relationships and personal experiences. Language may accordingly have evolved to allow individuals to learn about the behavioural characteristics of other group members more rapidly than was feasible by direct observation alone.",
    url = "https://doi.org/10.1017/s0140525x00032325",
    doi = "10.1017/s0140525x00032325",
    openalex = "W2137391072",
    references = "doi1010079781468441482, doi1010160022519364900384, doi1010160047248487900224, doi101016004724849290081j, doi101016s0022519389801699, doi101017s0140525x00081061, doi101086284325, doi101093oso97801985464120010001, doi101098rstb19890106, doi101111j143903101963tb01161x, doi101152physrev1992721165, doi1023071367778, doi1023071438156, doi1023072063068, doi1023072185913, doi1023072407154, doi1043249780203037416, doi1043249781315132129, doi105860choice295104, falk1983cerebral, openalexw1659631989, openalexw1996270497"
}

Abstract In both biology and the human sciences, social groups are sometimes treated as adaptive units whose organization cannot be reduced to individual interactions. This group-level view is opposed by a more individualistic one that treats social organization as a byproduct of self-interest. According to biologists, group-level adaptations can evolve only by a process of natural selection at the group level. Most biologists rejected group selection as an important evolutionary force during the 1960s and 1970s but a positive literature began to grow during the 1970s and is rapidly expanding today. We review this recent literature and its implications for human evolutionary biology. We show that the rejection of group selection was based on a misplaced emphasis on genes as “replicators” which is in fact irrelevant to the question of whether groups can be like individuals in their functional organization. The fundamental question is whether social groups and other higher-level entities can be “vehicles” of selection. When this elementary fact is recognized, group selection emerges as an important force in nature and what seem to be competing theories, such as kin selection and reciprocity, reappear as special cases of group selection. The result is a unified theory of natural selection that operates on a nested hierarchy of units. The vehicle-based theory makes it clear that group selection is an important force to consider in human evolution. Humans can facultatively span the full range from self-interested individuals to “organs” of group-level “organisms.” Human behavior not only reflects the balance between levels of selection but it can also alter the balance through the construction of social structures that have the effect of reducing fitness differences within groups, concentrating natural selection (and functional organization) at the group level. These social structures and the cognitive abilities that produce them allow group selection to be important even among large groups of unrelated individuals.

@article{doi101017s0140525x00036104,
    author = "Wilson, David Sloan and Sober, Elliott",
    title = "Reintroducing group selection to the human behavioral sciences",
    year = "1994",
    journal = "Behavioral and Brain Sciences",
    abstract = "Abstract In both biology and the human sciences, social groups are sometimes treated as adaptive units whose organization cannot be reduced to individual interactions. This group-level view is opposed by a more individualistic one that treats social organization as a byproduct of self-interest. According to biologists, group-level adaptations can evolve only by a process of natural selection at the group level. Most biologists rejected group selection as an important evolutionary force during the 1960s and 1970s but a positive literature began to grow during the 1970s and is rapidly expanding today. We review this recent literature and its implications for human evolutionary biology. We show that the rejection of group selection was based on a misplaced emphasis on genes as “replicators” which is in fact irrelevant to the question of whether groups can be like individuals in their functional organization. The fundamental question is whether social groups and other higher-level entities can be “vehicles” of selection. When this elementary fact is recognized, group selection emerges as an important force in nature and what seem to be competing theories, such as kin selection and reciprocity, reappear as special cases of group selection. The result is a unified theory of natural selection that operates on a nested hierarchy of units. The vehicle-based theory makes it clear that group selection is an important force to consider in human evolution. Humans can facultatively span the full range from self-interested individuals to “organs” of group-level “organisms.” Human behavior not only reflects the balance between levels of selection but it can also alter the balance through the construction of social structures that have the effect of reducing fitness differences within groups, concentrating natural selection (and functional organization) at the group level. These social structures and the cognitive abilities that produce them allow group selection to be important even among large groups of unrelated individuals.",
    url = "https://doi.org/10.1017/s0140525x00036104",
    doi = "10.1017/s0140525x00036104",
    openalex = "W2091199874",
    references = "doi101007bf00129882, doi1010160022519364900384, doi101016s0022519389801699, doi101016s0065345408603526, doi101017s0140525x00029939, doi10103712293000, doi101073pnas722646, doi101086406755, doi101086410450, doi101093genetics16297, doi101111j143903101978tb01823x, doi101111j155856461977tb00991x, doi101111j155856461984tb00344x, doi101111j204483091987tb00799x, doi101126science16238591243, doi101126science7466396, doi101146annureves01110170000245, doi1015159781400858712, doi1015159781503621534, doi101537ase188722495, doi1023072026633, doi1023072026953, doi1023072529912, doi105962bhltitle2092, doi105962bhltitle27468, doi107208chicago97802261495160010001, goodnight1992contextual, nunney1985group, openalexw2616504082, openalexw2624262714, openalexw645218623"
}

The evolutionary problem of the units of selection has elicited a good deal of conceptual work from philosophers. We review this work to determine where the issues now stand.

@article{doi101086289821,
    author = "Sober, Elliott and Wilson, David Sloan",
    title = "A Critical Review of Philosophical Work on the Units of Selection Problem",
    year = "1994",
    journal = "Philosophy of Science",
    abstract = "The evolutionary problem of the units of selection has elicited a good deal of conceptual work from philosophers. We review this work to determine where the issues now stand.",
    url = "https://doi.org/10.1086/289821",
    doi = "10.1086/289821",
    openalex = "W1988503266",
    references = "doi1023072026633"
}

Once upon a time in evolutionary theory, everything happened for the best. Predators killed only the old or the sick. Pecking orders and other dominance hierarchies minimized wasteful conflict within the group. Male displays ensured that only the best and the fittest had mates. In the culmination of this tradition, Wynne-Edwards (1962, 1986) argued that many species have mechanisms that ensure groups do not over-exploit their resource base. The “central function” of territoriality in birds and other higher animals is “of limiting the numbers of occupants per unit area of habitat” (1986, 6). Species with dominance hierarchies, species with lekking breeding systems, and species with communal breeding regulate their populations. These social mechanisms have population regulation as their “underlying primary function” (1986, 9). Wynne-Edwards argued that these mechanisms evolve through group selection. Populations without such mechanisms are apt to go extinct by eroding their own resource base.

@article{doi101086289977,
    author = "Sterelny, Kim",
    title = "The Return of the Group",
    year = "1996",
    journal = "Philosophy of Science",
    abstract = "Once upon a time in evolutionary theory, everything happened for the best. Predators killed only the old or the sick. Pecking orders and other dominance hierarchies minimized wasteful conflict within the group. Male displays ensured that only the best and the fittest had mates. In the culmination of this tradition, Wynne-Edwards (1962, 1986) argued that many species have mechanisms that ensure groups do not over-exploit their resource base. The “central function” of territoriality in birds and other higher animals is “of limiting the numbers of occupants per unit area of habitat” (1986, 6). Species with dominance hierarchies, species with lekking breeding systems, and species with communal breeding regulate their populations. These social mechanisms have population regulation as their “underlying primary function” (1986, 9). Wynne-Edwards argued that these mechanisms evolve through group selection. Populations without such mechanisms are apt to go extinct by eroding their own resource base.",
    url = "https://doi.org/10.1086/289977",
    doi = "10.1086/289977",
    openalex = "W1972346449",
    references = "doi1010029780470996362ch12, doi101017s0140525x00036104, doi1010382011145a0, doi101093oso97801950693270010001, doi1015159781400820108, doi1023072174952, doi1023072828, doi105860choice304384, openalexw2624262714, openalexw2798374369"
}

@article{doi101006redy19980023,
    author = "Levine, David K.",
    title = "Modeling Altruism and Spitefulness in Experiments",
    year = "1998",
    journal = "Review of Economic Dynamics",
    url = "https://doi.org/10.1006/redy.1998.0023",
    doi = "10.1006/redy.1998.0023",
    openalex = "W2099758346",
    references = "doi101006game19951023, doi1010160022053182900308, doi101016002205318290031x, doi1015159780691213255, doi1015159780691213255004, doi1023071882648, doi1023071885060, doi1023071912767, doi102307jctvcm4j8j15, doi102307jctvzsmff5"
}

Social insects so dominate many terrestrial habitats (Wilson 1990) that they can hardly escape the attention of biologists, but even if they were rare, they would still attract special interest because of the intricate cooperation within their societies. William Morton Wheeler (1911) described the social insect colony as an organism (or as a higher-level organism or superorganism) because of the degree to which individuals appear to operate as a unit that is dedicated to the perpetuation and reproduction of the colony as a whole. The reinvention of the organism at a higher level has occurred at a number of crucial junctures in the history of life (Maynard Smith and Szathmary 1995). For example, the eukaryotic cell arose from several prokaryotic ancestors (Margulis 1970), and multicellular plants, animals, and fungi arose from single-celled ancestors (Buss 1987). Because insect societies are macroscopic, and because they span the entire range from solitary individuals to essentially superorganismal colonies, they offer an accessible model for how such transitions can happen.

@article{doi1023071313262,
    author = "Queller, David C. and Strassmann, Joan E.",
    title = "Kin Selection and Social Insects",
    year = "1998",
    journal = "BioScience",
    abstract = "Social insects so dominate many terrestrial habitats (Wilson 1990) that they can hardly escape the attention of biologists, but even if they were rare, they would still attract special interest because of the intricate cooperation within their societies. William Morton Wheeler (1911) described the social insect colony as an organism (or as a higher-level organism or superorganism) because of the degree to which individuals appear to operate as a unit that is dedicated to the perpetuation and reproduction of the colony as a whole. The reinvention of the organism at a higher level has occurred at a number of crucial junctures in the history of life (Maynard Smith and Szathmary 1995). For example, the eukaryotic cell arose from several prokaryotic ancestors (Margulis 1970), and multicellular plants, animals, and fungi arose from single-celled ancestors (Buss 1987). Because insect societies are macroscopic, and because they span the entire range from solitary individuals to essentially superorganismal colonies, they offer an accessible model for how such transitions can happen.",
    url = "https://doi.org/10.2307/1313262",
    doi = "10.2307/1313262",
    openalex = "W2096291488",
    references = "doi101016s0022519389801699"
}

Social interactions often affect the fitness of interactants. Because of this, social selection has been described as a process distinct from other forms of natural selection. Social selection has been predicted to result in different evolutionary dynamics for interacting phenotypes, including rapid or extreme evolution and evolution of altruism. Despite the critical role that social selection plays in theories of social evolution, few studies have measured the force of social selection or the conditions under which this force changes. Here we present a model of social selection acting on interacting phenotypes that can be evaluated independently from the genetics of interacting phenotypes. Our model of social selection is analogous to covariance models of other forms of selection. We observe that an opportunity for social selection exists whenever individual fitness varies as a result of interactions with conspecifics. Social selection occurs, therefore, when variation in fitness due to interactions covaries with traits, resulting in a net force of selection acting on the interacting phenotypes. Thus, there must be a covariance between the phenotypes of the interactants for social selection to exist. This interacting phenotype covariance is important because it measures the degree to which a particular trait covaries with the selective environment provided by conspecifics. A variety of factors, including nonrandom interactions, behavioral modification during interactions, relatedness, and indirect genetic effects may contribute to the covariance of interacting phenotypes, which promotes social selection. The independent force of social selection (measured as a social selection gradient) can be partitioned empirically from the force of natural selection (measured by the natural selection gradient) using partial regression. This measure can be combined with genetic models of interacting phenotypes to provide insights into social evolution.

@article{doi101086303168,
    author = "Wolf, Jason B. and Brodie, Edmund D. and Moore, Allen J.",
    title = "Interacting Phenotypes and the Evolutionary Process. II. Selection Resulting from Social Interactions",
    year = "1999",
    journal = "The American Naturalist",
    abstract = "Social interactions often affect the fitness of interactants. Because of this, social selection has been described as a process distinct from other forms of natural selection. Social selection has been predicted to result in different evolutionary dynamics for interacting phenotypes, including rapid or extreme evolution and evolution of altruism. Despite the critical role that social selection plays in theories of social evolution, few studies have measured the force of social selection or the conditions under which this force changes. Here we present a model of social selection acting on interacting phenotypes that can be evaluated independently from the genetics of interacting phenotypes. Our model of social selection is analogous to covariance models of other forms of selection. We observe that an opportunity for social selection exists whenever individual fitness varies as a result of interactions with conspecifics. Social selection occurs, therefore, when variation in fitness due to interactions covaries with traits, resulting in a net force of selection acting on the interacting phenotypes. Thus, there must be a covariance between the phenotypes of the interactants for social selection to exist. This interacting phenotype covariance is important because it measures the degree to which a particular trait covaries with the selective environment provided by conspecifics. A variety of factors, including nonrandom interactions, behavioral modification during interactions, relatedness, and indirect genetic effects may contribute to the covariance of interacting phenotypes, which promotes social selection. The independent force of social selection (measured as a social selection gradient) can be partitioned empirically from the force of natural selection (measured by the natural selection gradient) using partial regression. This measure can be combined with genetic models of interacting phenotypes to provide insights into social evolution.",
    url = "https://doi.org/10.1086/303168",
    doi = "10.1086/303168",
    openalex = "W2071931278",
    references = "doi101007978146847862422, doi1010160022519364900384, doi101016s001600323892229x, doi101017cbo9780511806292, doi101046j14390388200200356x, doi101111j155856461983tb00236x, doi101126science7466396, doi1023072529912, doi104159harvard9780674865327, goodnight1992contextual, openalexw2624262714"
}

The group selection controversy is about whether natural selection ever operates at the level of groups, rather than at the level of individual organisms. Traditionally, group selection has been invoked to explain the existence of altruistic behaviour in nature. However, most contemporary evolutionary biologists are highly sceptical of the hypothesis of group selection, which they regard as biologically implausible and not needed to explain the evolution of altruism anyway. But in their recent book, Elliot Sober and David Sloan Wilson [1998] argue that the widespread opposition to group selection is founded on conceptual confusion. The theories that have been propounded as alternatives to group selection are actually group selection in disguise, they maintain. I examine their arguments for this claim, and John Maynard Smith's arguments against it. I argue that Sober and Wilson arrive at a correct position by faulty reasoning. In the final section, I examine the issue of how to apply the principle of natural selection at different levels of the biological hierarchy, which underlies the dispute between Sober and Wilson and Maynard Smith.

@article{doi101093bjps52125,
    author = "Okasha, Samir",
    title = "Why Won't the Group Selection Controversy Go Away?",
    year = "2001",
    journal = "The British Journal for the Philosophy of Science",
    abstract = "The group selection controversy is about whether natural selection ever operates at the level of groups, rather than at the level of individual organisms. Traditionally, group selection has been invoked to explain the existence of altruistic behaviour in nature. However, most contemporary evolutionary biologists are highly sceptical of the hypothesis of group selection, which they regard as biologically implausible and not needed to explain the evolution of altruism anyway. But in their recent book, Elliot Sober and David Sloan Wilson [1998] argue that the widespread opposition to group selection is founded on conceptual confusion. The theories that have been propounded as alternatives to group selection are actually group selection in disguise, they maintain. I examine their arguments for this claim, and John Maynard Smith's arguments against it. I argue that Sober and Wilson arrive at a correct position by faulty reasoning. In the final section, I examine the issue of how to apply the principle of natural selection at different levels of the biological hierarchy, which underlies the dispute between Sober and Wilson and Maynard Smith.",
    url = "https://doi.org/10.1093/bjps/52.1.25",
    doi = "10.1093/bjps/52.1.25",
    openalex = "W1984721570",
    references = "doi101086289977"
}

We study gender differences in altruism by examining a modified dictator game with varying incomes and prices. Our results indicate that the question “which is the fair sex?” has a complicated answer—when altruism is expensive, women are kinder, but when it is cheap, men are more altruistic. That is, we find that the male and female “demand curves for altruism” cross, and that men are more responsive to price changes. Furthermore, men are more likely to be either perfectly selfish or perfectly selfless, whereas women tend to be “equalitarians” who prefer to share evenly.

@article{doi101162003355301556419,
    author = "Andreoni, James and Vesterlund, Lise",
    title = "Which is the Fair Sex? Gender Differences in Altruism",
    year = "2001",
    journal = "The Quarterly Journal of Economics",
    abstract = "We study gender differences in altruism by examining a modified dictator game with varying incomes and prices. Our results indicate that the question “which is the fair sex?” has a complicated answer—when altruism is expensive, women are kinder, but when it is cheap, men are more altruistic. That is, we find that the male and female “demand curves for altruism” cross, and that men are more responsive to price changes. Furthermore, men are more likely to be either perfectly selfish or perfectly selfless, whereas women tend to be “equalitarians” who prefer to share evenly.",
    url = "https://doi.org/10.1162/003355301556419",
    doi = "10.1162/003355301556419",
    openalex = "W2146576574",
    references = "doi101006game19941021, doi101016004727279490068x, doi101016s0167487097000263, doi1011111468029700311, doi101111j146572951998tb01740x, doi101257aer892386, doi101257pandp109612, doi1023071420596, openalexw2297612634, openalexw3213526873"
}

@article{barrett2002group,
    author = "BARRETT, MATTHEW and GODFREY‐SMITH, PETER",
    title = "Group Selection, Pluralism, and the Evolution of Altruism",
    year = "2002",
    journal = "Philosophy and Phenomenological Research",
    url = "https://doi.org/10.1111/j.1933-1592.2002.tb00233.x",
    doi = "10.1111/j.1933-1592.2002.tb00233.x",
    number = "3",
    openalex = "W2001924915",
    pages = "685-691",
    volume = "65",
    references = "doi101007bf00129882, doi101016s0065345408603526, doi10103831383, doi101046j14390310199900372x, doi101086289977, doi1023072026633, doi1023072026953"
}

We distinguish dynamical and statistical interpretations of evolutionary theory. We argue that only the statistical interpretation preserves the presumed relation between natural selection and drift. On these grounds we claim that the dynamical conception of evolutionary theory as a theory of forces is mistaken. Selection and drift are not forces. Nor do selection and drift explanations appeal to the (sub-population-level) causes of population level change. Instead they explain by appeal to the statistical structure of populations. We briefly discuss the implications of the statistical interpretation of selection for various debates within the philosophy of biology—the ‘explananda of selection’ debate and the ‘units of selection’ debate.

@article{doi101086342454,
    author = "Walsh, Denis M. and Lewens, Tim and Ariew, André",
    title = "The Trials of Life: Natural Selection and Random Drift",
    year = "2002",
    journal = "Philosophy of Science",
    abstract = "We distinguish dynamical and statistical interpretations of evolutionary theory. We argue that only the statistical interpretation preserves the presumed relation between natural selection and drift. On these grounds we claim that the dynamical conception of evolutionary theory as a theory of forces is mistaken. Selection and drift are not forces. Nor do selection and drift explanations appeal to the (sub-population-level) causes of population level change. Instead they explain by appeal to the statistical structure of populations. We briefly discuss the implications of the statistical interpretation of selection for various debates within the philosophy of biology—the ‘explananda of selection’ debate and the ‘units of selection’ debate.",
    url = "https://doi.org/10.1086/342454",
    doi = "10.1086/342454",
    openalex = "W2025946306",
    references = "doi1023072026953"
}

Abstract Prosocial behavior covers the broad range of actions intended to benefit one or more people other than oneself—actions such as helping, comforting, sharing, and cooperation. Altruism is motivation to increase another person's welfare; it is contrasted to egoism, the motivation to increase one's own welfare. There is no one‐to‐one correspondence between prosocial behavior and altruism. Prosocial behavior need not be motivated by altruism; altruistic motivation need not produce prosocial behavior. Over the past 30 years, the practical concern to promote prosocial behavior has led to both a variance‐accounted‐for empirical approach, which focuses on identifying situational and dispositional determinants of helping, and the application of existing psychological theories. Theories invoked to explain prosocial behavior include social learning, tension reduction, norm, exchange or equity, attribution, esteem‐enhancement, and moral reasoning theories. In addition, new theoretical perspectives have been developed by researchers focused on anomalous aspects of why people do—and don't—act prosocially. Their research has raised the possibility of a multiplicity of social motives—altruism, collectivism, and principlism, as well as egoism. It has also raised questions—as yet unanswered—about how these motives might be most effectively orchestrated to increase prosocial behavior.

@article{doi1010020471264385wei0519,
    author = "Batson, C. Daniel and Powell, Adam A.",
    title = "Altruism and Prosocial Behavior",
    year = "2003",
    journal = "Handbook of Psychology",
    abstract = "Abstract Prosocial behavior covers the broad range of actions intended to benefit one or more people other than oneself—actions such as helping, comforting, sharing, and cooperation. Altruism is motivation to increase another person's welfare; it is contrasted to egoism, the motivation to increase one's own welfare. There is no one‐to‐one correspondence between prosocial behavior and altruism. Prosocial behavior need not be motivated by altruism; altruistic motivation need not produce prosocial behavior. Over the past 30 years, the practical concern to promote prosocial behavior has led to both a variance‐accounted‐for empirical approach, which focuses on identifying situational and dispositional determinants of helping, and the application of existing psychological theories. Theories invoked to explain prosocial behavior include social learning, tension reduction, norm, exchange or equity, attribution, esteem‐enhancement, and moral reasoning theories. In addition, new theoretical perspectives have been developed by researchers focused on anomalous aspects of why people do—and don't—act prosocially. Their research has raised the possibility of a multiplicity of social motives—altruism, collectivism, and principlism, as well as egoism. It has also raised questions—as yet unanswered—about how these motives might be most effectively orchestrated to increase prosocial behavior.",
    url = "https://doi.org/10.1002/0471264385.wei0519",
    doi = "10.1002/0471264385.wei0519",
    openalex = "W2110472749",
    references = "doi101016s0065260108601082, doi101016s0065260108603585, doi101016s0065260122x00026, doi10103710628000, doi101111j204483091987tb00799x, doi1015159781503620766, doi1023072067520, doi1023072092623, doi1023073340496, doi104324978100332060959"
}

@article{cooper2004group,
    author = "Cooper, B.",
    title = "Group selection and the evolution of altruism",
    year = "2004",
    journal = "Oxford Economic Papers",
    url = "https://doi.org/10.1093/oep/gpf043",
    doi = "10.1093/oep/gpf043",
    number = "2",
    openalex = "W2098687748",
    pages = "307-330",
    volume = "56",
    references = "doi1010160022519364900384, doi101017cbo9780511493607, doi1010382011145a0, doi101046j14390310199900372x, doi101073pnas721143, doi101111j251761611951tb00088x, doi101537ase188722495, doi105962bhltitle2112, openalexw1494315736, openalexw2624262714"
}

Estimating the genetic basis of quantitative traits can be tricky for wild populations in natural environments, as environmental variation frequently obscures the underlying evolutionary patterns. I review the recent application of restricted maximum-likelihood "animal models" to multigenerational data from natural populations, and show how the estimation of variance components and prediction of breeding values using these methods offer a powerful means of tackling the potentially confounding effects of environmental variation, as well as generating a wealth of new areas of investigation.

@article{doi101098rstb20031437,
    author = "Kruuk, Loeske E. B.",
    title = "Estimating genetic parameters in natural populations using the ‘animal model’",
    year = "2004",
    journal = "Philosophical Transactions of the Royal Society B Biological Sciences",
    abstract = {Estimating the genetic basis of quantitative traits can be tricky for wild populations in natural environments, as environmental variation frequently obscures the underlying evolutionary patterns. I review the recent application of restricted maximum-likelihood "animal models" to multigenerational data from natural populations, and show how the estimation of variance components and prediction of breeding values using these methods offer a powerful means of tackling the potentially confounding effects of environmental variation, as well as generating a wealth of new areas of investigation.},
    url = "https://doi.org/10.1098/rstb.2003.1437",
    doi = "10.1098/rstb.2003.1437",
    openalex = "W2073035337",
    references = "doi101016s0169534702000447, doi101038nrg700, doi101111j155856461984tb00344x, doi105860choice355054"
}

Group selection is one acknowledged mechanism for the evolution of altruism. It is well known that for altruism to spread by natural selection, interactions must be correlated; that is, altruists must tend to associate with one another. But does group selection itself require correlated interactions? Two possible arguments for answering this question affirmatively are explored. The first is a bad argument, for it rests on a product/process confusion. The second is a more subtle argument, whose validity (or otherwise) turns on issues concerning the meaning of multi-level selection and how it should be modelled. A cautious defence of the second argument is offered. 1. Introduction 2. Multi-level selection and the evolution of altruism 3. Price's equation and multi-level selection 4. Contextual analysis and multi-level selection 5. The neighbour approach 6. Recapitulation and conclusion

@article{doi101093bjpsaxi143,
    author = "Okasha, Samir",
    title = "Altruism, Group Selection and Correlated Interaction",
    year = "2005",
    journal = "The British Journal for the Philosophy of Science",
    abstract = "Group selection is one acknowledged mechanism for the evolution of altruism. It is well known that for altruism to spread by natural selection, interactions must be correlated; that is, altruists must tend to associate with one another. But does group selection itself require correlated interactions? Two possible arguments for answering this question affirmatively are explored. The first is a bad argument, for it rests on a product/process confusion. The second is a more subtle argument, whose validity (or otherwise) turns on issues concerning the meaning of multi-level selection and how it should be modelled. A cautious defence of the second argument is offered. 1. Introduction 2. Multi-level selection and the evolution of altruism 3. Price's equation and multi-level selection 4. Contextual analysis and multi-level selection 5. The neighbour approach 6. Recapitulation and conclusion",
    url = "https://doi.org/10.1093/bjps/axi143",
    doi = "10.1093/bjps/axi143",
    openalex = "W2134905101",
    references = "doi101007bf00129882"
}

The Trust Game is regarded as an important model of corporate culture in that social learning to promote trust creates organizational efficiencies consistent with the existence of firms. We examine the Trust Game from an evolutionary perspective in which player types are defined in terms of their commitment to trustworthy behavior. In so doing, a condition for multilevel selection (group effects) is identified. When group effects exist—implying that the matching process is not independent of players' commitment—a corporate culture emerges that promotes trust. This results in an evolutionary theory of business ethics.

@article{doi101002j232580122006tb00755x,
    author = "Arce, Daniel G.",
    title = "Taking Corporate Culture Seriously: Group Effects in the Trust Game",
    year = "2006",
    journal = "Southern Economic Journal",
    abstract = "The Trust Game is regarded as an important model of corporate culture in that social learning to promote trust creates organizational efficiencies consistent with the existence of firms. We examine the Trust Game from an evolutionary perspective in which player types are defined in terms of their commitment to trustworthy behavior. In so doing, a condition for multilevel selection (group effects) is identified. When group effects exist—implying that the matching process is not independent of players' commitment—a corporate culture emerges that promotes trust. This results in an evolutionary theory of business ethics.",
    url = "https://doi.org/10.1002/j.2325-8012.2006.tb00755.x",
    doi = "10.1002/j.2325-8012.2006.tb00755.x",
    openalex = "W2026185580",
    references = "cooper2004group, doi1010160160932782900369, doi1010160167268185900174, doi101016s0167268103000945, doi101017cbo9780511571657006, doi101017s0140525x00036104, doi101038227520a0, doi101093oso97801987743580030005, doi101111j251761611951tb00088x, doi1023071061220, openalexw1512416168"
}

We propose a minimalist stochastic model of multilevel (or group) selection. A population is subdivided into groups. Individuals interact with other members of the group in an evolutionary game that determines their fitness. Individuals reproduce, and offspring are added to the same group. If a group reaches a certain size, it can split into two. Faster reproducing individuals lead to larger groups that split more often. In our model, higher-level selection emerges as a byproduct of individual reproduction and population structure. We derive a fundamental condition for the evolution of cooperation by group selection: if b/c > 1 + n/m, then group selection favors cooperation. The parameters b and c denote the benefit and cost of the altruistic act, whereas n and m denote the maximum group size and the number of groups. The model can be extended to more than two levels of selection and to include migration.

@article{doi101073pnas0602530103,
    author = "Traulsen, Arne and Nowak, Martin A.",
    title = "Evolution of cooperation by multilevel selection",
    year = "2006",
    journal = "Proceedings of the National Academy of Sciences",
    abstract = "We propose a minimalist stochastic model of multilevel (or group) selection. A population is subdivided into groups. Individuals interact with other members of the group in an evolutionary game that determines their fitness. Individuals reproduce, and offspring are added to the same group. If a group reaches a certain size, it can split into two. Faster reproducing individuals lead to larger groups that split more often. In our model, higher-level selection emerges as a byproduct of individual reproduction and population structure. We derive a fundamental condition for the evolution of cooperation by group selection: if b/c > 1 + n/m, then group selection favors cooperation. The parameters b and c denote the benefit and cost of the altruistic act, whereas n and m denote the maximum group size and the number of groups. The model can be extended to more than two levels of selection and to include migration.",
    url = "https://doi.org/10.1073/pnas.0602530103",
    doi = "10.1073/pnas.0602530103",
    openalex = "W2009481751",
    references = "doi101023a1020504900646, doi101038nature01906, doi101111j155856461977tb00991x, nunney1985group, openalexw645218623"
}

Does natural selection act primarily on individual organisms, on groups, on genes, or on whole species? This book provides a comprehensive analysis of the debate in evolutionary biology over the levels of selection, focusing on conceptual philosophical and foundational questions.

@book{doi101093acprofoso97801992679720010001,
    author = "Okasha, Samir",
    title = "Evolution and the Levels of Selection",
    year = "2006",
    booktitle = "Oxford University Press eBooks",
    abstract = "Does natural selection act primarily on individual organisms, on groups, on genes, or on whole species? This book provides a comprehensive analysis of the debate in evolutionary biology over the levels of selection, focusing on conceptual philosophical and foundational questions.",
    url = "https://doi.org/10.1093/acprof:oso/9780199267972.001.0001",
    doi = "10.1093/acprof:oso/9780199267972.001.0001",
    openalex = "W2098069022",
    references = "doi1010020470099704, doi101525bio20106059, doi105860choice396411, doi105962bhltitle3163"
}

One of the enduring puzzles in biology and the social sciences is the origin and persistence of intraspecific cooperation and altruism in humans and other species. Hundreds of theoretical models have been proposed and there is much confusion about the relationship between these models. To clarify the situation, we developed a synthetic conceptual framework that delineates the conditions necessary for the evolution of altruism and cooperation. We show that at least one of the four following conditions needs to be fulfilled: direct benefits to the focal individual performing a cooperative act; direct or indirect information allowing a better than random guess about whether a given individual will behave cooperatively in repeated reciprocal interactions; preferential interactions between related individuals; and genetic correlation between genes coding for altruism and phenotypic traits that can be identified. When one or more of these conditions are met, altruism or cooperation can evolve if the cost-to-benefit ratio of altruistic and cooperative acts is greater than a threshold value. The cost-to-benefit ratio can be altered by coercion, punishment and policing which therefore act as mechanisms facilitating the evolution of altruism and cooperation. All the models proposed so far are explicitly or implicitly built on these general principles, allowing us to classify them into four general categories.

@article{doi101111j14209101200601119x,
    author = "Lehmann, Laurent and Keller, Laurent",
    title = "The evolution of cooperation and altruism – a general framework and a classification of models",
    year = "2006",
    journal = "Journal of Evolutionary Biology",
    abstract = "One of the enduring puzzles in biology and the social sciences is the origin and persistence of intraspecific cooperation and altruism in humans and other species. Hundreds of theoretical models have been proposed and there is much confusion about the relationship between these models. To clarify the situation, we developed a synthetic conceptual framework that delineates the conditions necessary for the evolution of altruism and cooperation. We show that at least one of the four following conditions needs to be fulfilled: direct benefits to the focal individual performing a cooperative act; direct or indirect information allowing a better than random guess about whether a given individual will behave cooperatively in repeated reciprocal interactions; preferential interactions between related individuals; and genetic correlation between genes coding for altruism and phenotypic traits that can be identified. When one or more of these conditions are met, altruism or cooperation can evolve if the cost-to-benefit ratio of altruistic and cooperative acts is greater than a threshold value. The cost-to-benefit ratio can be altered by coercion, punishment and policing which therefore act as mechanisms facilitating the evolution of altruism and cooperation. All the models proposed so far are explicitly or implicitly built on these general principles, allowing us to classify them into four general categories.",
    url = "https://doi.org/10.1111/j.1420-9101.2006.01119.x",
    doi = "10.1111/j.1420-9101.2006.01119.x",
    openalex = "W2112573298",
    references = "doi101016s0065345408603526, doi101086383541, nunney1985group"
}

From an evolutionary perspective, social behaviours are those which have fitness consequences for both the individual that performs the behaviour, and another individual. Over the last 43 years, a huge theoretical and empirical literature has developed on this topic. However, progress is often hindered by poor communication between scientists, with different people using the same term to mean different things, or different terms to mean the same thing. This can obscure what is biologically important, and what is not. The potential for such semantic confusion is greatest with interdisciplinary research. Our aim here is to address issues of semantic confusion that have arisen with research on the problem of cooperation. In particular, we: (i) discuss confusion over the terms kin selection, mutualism, mutual benefit, cooperation, altruism, reciprocal altruism, weak altruism, altruistic punishment, strong reciprocity, group selection and direct fitness; (ii) emphasize the need to distinguish between proximate (mechanism) and ultimate (survival value) explanations of behaviours. We draw examples from all areas, but especially recent work on humans and microbes.

@article{doi101111j14209101200601258x,
    author = "West, Stuart A. and Griffin, Ashleigh S. and Gardner, Andy",
    title = "Social semantics: altruism, cooperation, mutualism, strong reciprocity and group selection",
    year = "2006",
    journal = "Journal of Evolutionary Biology",
    abstract = "From an evolutionary perspective, social behaviours are those which have fitness consequences for both the individual that performs the behaviour, and another individual. Over the last 43 years, a huge theoretical and empirical literature has developed on this topic. However, progress is often hindered by poor communication between scientists, with different people using the same term to mean different things, or different terms to mean the same thing. This can obscure what is biologically important, and what is not. The potential for such semantic confusion is greatest with interdisciplinary research. Our aim here is to address issues of semantic confusion that have arisen with research on the problem of cooperation. In particular, we: (i) discuss confusion over the terms kin selection, mutualism, mutual benefit, cooperation, altruism, reciprocal altruism, weak altruism, altruistic punishment, strong reciprocity, group selection and direct fitness; (ii) emphasize the need to distinguish between proximate (mechanism) and ultimate (survival value) explanations of behaviours. We draw examples from all areas, but especially recent work on humans and microbes.",
    url = "https://doi.org/10.1111/j.1420-9101.2006.01258.x",
    doi = "10.1111/j.1420-9101.2006.01258.x",
    openalex = "W2124337033",
    references = "doi101006jtbi20002111, doi101016s0065345408603526, doi101016s1090513804000054, doi1010382011145a0, doi101046j14390310199900372x, doi101073pnas721143, doi101086383541, doi101093oso97801985029440010001, doi101111j143903101963tb01161x, doi101111j155856461995tb04464x, doi101126science1563774477, doi1015159780691206820, doi1023072828, openalexw2616504082"
}

Humans behave altruistically in natural settings and experiments. A possible explanation-that groups with more altruists survive when groups compete-has long been judged untenable on empirical grounds for most species. But there have been no empirical tests of this explanation for humans. My empirical estimates show that genetic differences between early human groups are likely to have been great enough so that lethal intergroup competition could account for the evolution of altruism. Crucial to this process were distinctive human practices such as sharing food beyond the immediate family, monogamy, and other forms of reproductive leveling. These culturally transmitted practices presuppose advanced cognitive and linguistic capacities, possibly accounting for the distinctive forms of altruism found in our species.

@article{doi101126science1134829,
    author = "Bowles, Samuel",
    title = "Group Competition, Reproductive Leveling, and the Evolution of Human Altruism",
    year = "2006",
    journal = "Science",
    abstract = "Humans behave altruistically in natural settings and experiments. A possible explanation-that groups with more altruists survive when groups compete-has long been judged untenable on empirical grounds for most species. But there have been no empirical tests of this explanation for humans. My empirical estimates show that genetic differences between early human groups are likely to have been great enough so that lethal intergroup competition could account for the evolution of altruism. Crucial to this process were distinctive human practices such as sharing food beyond the immediate family, monogamy, and other forms of reproductive leveling. These culturally transmitted practices presuppose advanced cognitive and linguistic capacities, possibly accounting for the distinctive forms of altruism found in our species.",
    url = "https://doi.org/10.1126/science.1134829",
    doi = "10.1126/science.1134829",
    openalex = "W2062414996"
}

Interaction among individuals is universal, both in animals and in plants, and substantially affects evolution of natural populations and responses to artificial selection in agriculture. Although quantitative genetics has successfully been applied to many traits, it does not provide a general theory accounting for interaction among individuals and selection acting on multiple levels. Consequently, current quantitative genetic theory fails to explain why some traits do not respond to selection among individuals, but respond greatly to selection among groups. Understanding the full impacts of heritable interactions on the outcomes of selection requires a quantitative genetic framework including all levels of selection and relatedness. Here we present such a framework and provide expressions for the response to selection. Results show that interaction among individuals may create substantial heritable variation, which is hidden to classical analyses. Selection acting on higher levels of organization captures this hidden variation and therefore always yields positive response, whereas individual selection may yield response in the opposite direction. Our work provides testable predictions of response to multilevel selection and reduces to classical theory in the absence of interaction. Statistical methodology provided elsewhere enables empirical application of our work to both natural and domestic populations.

@article{doi101534genetics106062711,
    author = "Bijma, Piter and Muir, William M. and van Arendonk, J.A.M.",
    title = "Multilevel Selection 1: Quantitative Genetics of Inheritance and Response to Selection",
    year = "2006",
    journal = "Genetics",
    abstract = "Interaction among individuals is universal, both in animals and in plants, and substantially affects evolution of natural populations and responses to artificial selection in agriculture. Although quantitative genetics has successfully been applied to many traits, it does not provide a general theory accounting for interaction among individuals and selection acting on multiple levels. Consequently, current quantitative genetic theory fails to explain why some traits do not respond to selection among individuals, but respond greatly to selection among groups. Understanding the full impacts of heritable interactions on the outcomes of selection requires a quantitative genetic framework including all levels of selection and relatedness. Here we present such a framework and provide expressions for the response to selection. Results show that interaction among individuals may create substantial heritable variation, which is hidden to classical analyses. Selection acting on higher levels of organization captures this hidden variation and therefore always yields positive response, whereas individual selection may yield response in the opposite direction. Our work provides testable predictions of response to multilevel selection and reduces to classical theory in the absence of interaction. Statistical methodology provided elsewhere enables empirical application of our work to both natural and domestic populations.",
    url = "https://doi.org/10.1534/genetics.106.062711",
    doi = "10.1534/genetics.106.062711",
    openalex = "W2132362070",
    references = "cooper2004group, doi1010160022519364900384, doi101016s0065345408603526, doi101038238413a0, doi10103835012234, doi101046j14390388200200356x, doi101111j146918091949tb02451x, doi101111j155856461965tb01731x, doi101111j155856461977tb00991x, doi101111j155856461983tb00236x, doi1023072408842, doi1023072529912, doi105962bhltitle27468, goodnight1992contextual"
}

Abstract Interactions among individuals are universal, both in animals and in plants and in natural as well as domestic populations. Understanding the consequences of these interactions for the evolution of populations by either natural or artificial selection requires knowledge of the heritable components underlying them. Here we present statistical methodology to estimate the genetic parameters determining response to multilevel selection of traits affected by interactions among individuals in general populations. We apply these methods to obtain estimates of genetic parameters for survival days in a population of layer chickens with high mortality due to pecking behavior. We find that heritable variation is threefold greater than that obtained from classical analyses, meaning that two-thirds of the full heritable variation is hidden to classical analysis due to social interactions. As a consequence, predicted responses to multilevel selection applied to this population are threefold greater than classical predictions. This work, combined with the quantitative genetic theory for response to multilevel selection presented in an accompanying article in this issue, enables the design of selection programs to effectively reduce competitive interactions in livestock and plants and the prediction of the effects of social interactions on evolution in natural populations undergoing multilevel selection.

@article{doi101534genetics106062729,
    author = "Bijma, Piter and Muir, William M. and Ellen, E.D. and Wolf, Jason B. and van Arendonk, J.A.M.",
    title = "Multilevel Selection 2: Estimating the Genetic Parameters Determining Inheritance and Response to Selection",
    year = "2006",
    journal = "Genetics",
    abstract = "Abstract Interactions among individuals are universal, both in animals and in plants and in natural as well as domestic populations. Understanding the consequences of these interactions for the evolution of populations by either natural or artificial selection requires knowledge of the heritable components underlying them. Here we present statistical methodology to estimate the genetic parameters determining response to multilevel selection of traits affected by interactions among individuals in general populations. We apply these methods to obtain estimates of genetic parameters for survival days in a population of layer chickens with high mortality due to pecking behavior. We find that heritable variation is threefold greater than that obtained from classical analyses, meaning that two-thirds of the full heritable variation is hidden to classical analysis due to social interactions. As a consequence, predicted responses to multilevel selection applied to this population are threefold greater than classical predictions. This work, combined with the quantitative genetic theory for response to multilevel selection presented in an accompanying article in this issue, enables the design of selection programs to effectively reduce competitive interactions in livestock and plants and the prediction of the effects of social interactions on evolution in natural populations undergoing multilevel selection.",
    url = "https://doi.org/10.1534/genetics.106.062729",
    doi = "10.1534/genetics.106.062729",
    openalex = "W2091207266",
    references = "doi101534genetics106062711"
}

Altruism-benefiting fellow group members at a cost to oneself-and parochialism-hostility toward individuals not of one's own ethnic, racial, or other group-are common human behaviors. The intersection of the two-which we term "parochial altruism"-is puzzling from an evolutionary perspective because altruistic or parochial behavior reduces one's payoffs by comparison to what one would gain by eschewing these behaviors. But parochial altruism could have evolved if parochialism promoted intergroup hostilities and the combination of altruism and parochialism contributed to success in these conflicts. Our game-theoretic analysis and agent-based simulations show that under conditions likely to have been experienced by late Pleistocene and early Holocene humans, neither parochialism nor altruism would have been viable singly, but by promoting group conflict, they could have evolved jointly.

@article{doi101126science1144237,
    author = "Choi, Jung-Kyoo and Bowles, Samuel",
    title = "The Coevolution of Parochial Altruism and War",
    year = "2007",
    journal = "Science",
    abstract = {Altruism-benefiting fellow group members at a cost to oneself-and parochialism-hostility toward individuals not of one's own ethnic, racial, or other group-are common human behaviors. The intersection of the two-which we term "parochial altruism"-is puzzling from an evolutionary perspective because altruistic or parochial behavior reduces one's payoffs by comparison to what one would gain by eschewing these behaviors. But parochial altruism could have evolved if parochialism promoted intergroup hostilities and the combination of altruism and parochialism contributed to success in these conflicts. Our game-theoretic analysis and agent-based simulations show that under conditions likely to have been experienced by late Pleistocene and early Holocene humans, neither parochialism nor altruism would have been viable singly, but by promoting group conflict, they could have evolved jointly.},
    url = "https://doi.org/10.1126/science.1144237",
    doi = "10.1126/science.1144237",
    openalex = "W2111240301",
    references = "doi101002evan20046, doi101006anbe20001706, doi101006jhev20000435, doi101007bf02270969, doi101007bf02270971, doi101038nature04981, doi101086203974, doi101086345689, doi101126science1134829, openalexw1529800964"
}

Evolutionary theory postulates that altruistic behavior evolved for the return-benefits it bears the performer. For return-benefits to play a motivational role, however, they need to be experienced by the organism. Motivational analyses should restrict themselves, therefore, to the altruistic impulse and its knowable consequences. Empathy is an ideal candidate mechanism to underlie so-called directed altruism, i.e., altruism in response to anothers's pain, need, or distress. Evidence is accumulating that this mechanism is phylogenetically ancient, probably as old as mammals and birds. Perception of the emotional state of another automatically activates shared representations causing a matching emotional state in the observer. With increasing cognition, state-matching evolved into more complex forms, including concern for the other and perspective-taking. Empathy-induced altruism derives its strength from the emotional stake it offers the self in the other's welfare. The dynamics of the empathy mechanism agree with predictions from kin selection and reciprocal altruism theory.

@article{doi101146annurevpsych59103006093625,
    author = "de Waal, Frans Β. Μ.",
    title = "Putting the Altruism Back into Altruism: The Evolution of Empathy",
    year = "2007",
    journal = "Annual Review of Psychology",
    abstract = "Evolutionary theory postulates that altruistic behavior evolved for the return-benefits it bears the performer. For return-benefits to play a motivational role, however, they need to be experienced by the organism. Motivational analyses should restrict themselves, therefore, to the altruistic impulse and its knowable consequences. Empathy is an ideal candidate mechanism to underlie so-called directed altruism, i.e., altruism in response to anothers's pain, need, or distress. Evidence is accumulating that this mechanism is phylogenetically ancient, probably as old as mammals and birds. Perception of the emotional state of another automatically activates shared representations causing a matching emotional state in the observer. With increasing cognition, state-matching evolved into more complex forms, including concern for the other and perspective-taking. Empathy-induced altruism derives its strength from the emotional stake it offers the self in the other's welfare. The dynamics of the empathy mechanism agree with predictions from kin selection and reciprocal altruism theory.",
    url = "https://doi.org/10.1146/annurev.psych.59.103006.093625",
    doi = "10.1146/annurev.psych.59.103006.093625",
    openalex = "W2134084792",
    references = "doi101002ajp1350020302, doi101002j153892351995tb03988x, doi1010160022519364900384, doi101017s0140525x02000018, doi10103700121649281126, doi101038nature04271, doi101046j14390310199900372x, doi101073pnas0608062103, doi101073pnas101086398, doi101086406755, doi101093oso97801950967360010001, doi101111j143903101963tb01161x, doi101126science1093535, doi105860choice294797, doi105860choice351500, openalexw1581387623, openalexw1849553904, openalexw2001431842, openalexw2126474339, openalexw2624262714"
}

Group-structured populations, of the kind prominent in discussions of multilevel selection, are contrasted with ‘neighbor-structured’ populations. I argue that it is a necessary condition on multilevel description of a selection process that there should be a nonarbitrary division of the population into equivalence classes (or an approximation to this situation). The discussion is focused via comparisons between two famous problem cases involving group structure (altruism and heterozygote advantage) and two neighbor-structured cases that resemble them. Conclusions are also drawn about the role of correlated interaction in the evolution of altruism. 1. Introduction2. Two Kinds of Population Structure3. Objections and Replies4. Particles on a Line5. ConclusionAppendix: Neighborhoods and Selection

@article{doi101093bjpsaxm044,
    author = "Godfrey‐Smith, Peter",
    title = "Varieties of Population Structure and the Levels of Selection",
    year = "2008",
    journal = "The British Journal for the Philosophy of Science",
    abstract = "Group-structured populations, of the kind prominent in discussions of multilevel selection, are contrasted with ‘neighbor-structured’ populations. I argue that it is a necessary condition on multilevel description of a selection process that there should be a nonarbitrary division of the population into equivalence classes (or an approximation to this situation). The discussion is focused via comparisons between two famous problem cases involving group structure (altruism and heterozygote advantage) and two neighbor-structured cases that resemble them. Conclusions are also drawn about the role of correlated interaction in the evolution of altruism. 1. Introduction2. Two Kinds of Population Structure3. Objections and Replies4. Particles on a Line5. ConclusionAppendix: Neighborhoods and Selection",
    url = "https://doi.org/10.1093/bjps/axm044",
    doi = "10.1093/bjps/axm044",
    openalex = "W1995109037",
    references = "doi101007bf00129882, doi101086289977"
}

We present a simple framework that highlights the most fundamental requirement for the evolution of altruism: assortment between individuals carrying the cooperative genotype and the helping behaviours of others with which these individuals interact. We partition the fitness effects on individuals into those due to self and those due to the 'interaction environment', and show that it is the latter that is most fundamental to understanding the evolution of altruism. We illustrate that while kinship or genetic similarity among those interacting may generate a favourable structure of interaction environments, it is not a fundamental requirement for the evolution of altruism, and even suicidal aid can theoretically evolve without help ever being exchanged among genetically similar individuals. Using our simple framework, we also clarify a common confusion made in the literature between alternative fitness accounting methods (which may equally apply to the same biological circumstances) and unique causal mechanisms for creating the assortment necessary for altruism to be favoured by natural selection.

@article{doi101098rspb20080829,
    author = "Fletcher, Jeffrey and Doebeli, Michael",
    title = "A simple and general explanation for the evolution of altruism",
    year = "2008",
    journal = "Proceedings of the Royal Society B Biological Sciences",
    abstract = "We present a simple framework that highlights the most fundamental requirement for the evolution of altruism: assortment between individuals carrying the cooperative genotype and the helping behaviours of others with which these individuals interact. We partition the fitness effects on individuals into those due to self and those due to the 'interaction environment', and show that it is the latter that is most fundamental to understanding the evolution of altruism. We illustrate that while kinship or genetic similarity among those interacting may generate a favourable structure of interaction environments, it is not a fundamental requirement for the evolution of altruism, and even suicidal aid can theoretically evolve without help ever being exchanged among genetically similar individuals. Using our simple framework, we also clarify a common confusion made in the literature between alternative fitness accounting methods (which may equally apply to the same biological circumstances) and unique causal mechanisms for creating the assortment necessary for altruism to be favoured by natural selection.",
    url = "https://doi.org/10.1098/rspb.2008.0829",
    doi = "10.1098/rspb.2008.0829",
    openalex = "W2019988542",
    references = "doi10103831383, nunney1985group"
}

Kin and levels-of-selection models are common approaches for modelling social evolution. Indirect genetic effect (IGE) models represent a different approach, specifying social effects on trait values rather than fitness. We investigate the joint effect of relatedness, multilevel selection and IGEs on response to selection. We present a measure for the degree of multilevel selection, which is the natural partner of relatedness in expressions for response. Response depends on both relatedness and the degree of multilevel selection, rather than only one or the other factor. Moreover, response is symmetric in relatedness and the degree of multilevel selection, indicating that both factors have exactly the same effect. Without IGEs, the key parameter is the product of relatedness and the degree of multilevel selection. With IGEs, however, multilevel selection without relatedness can explain evolution of social traits. Thus, next to relatedness and multilevel selection, IGEs are a key element in the genetical theory of social evolution.

@article{doi101111j14209101200801550x,
    author = "Bijma, Piter and Wade, Michael J.",
    title = "The joint effects of kin, multilevel selection and indirect genetic effects on response to genetic selection",
    year = "2008",
    journal = "Journal of Evolutionary Biology",
    abstract = "Kin and levels-of-selection models are common approaches for modelling social evolution. Indirect genetic effect (IGE) models represent a different approach, specifying social effects on trait values rather than fitness. We investigate the joint effect of relatedness, multilevel selection and IGEs on response to selection. We present a measure for the degree of multilevel selection, which is the natural partner of relatedness in expressions for response. Response depends on both relatedness and the degree of multilevel selection, rather than only one or the other factor. Moreover, response is symmetric in relatedness and the degree of multilevel selection, indicating that both factors have exactly the same effect. Without IGEs, the key parameter is the product of relatedness and the degree of multilevel selection. With IGEs, however, multilevel selection without relatedness can explain evolution of social traits. Thus, next to relatedness and multilevel selection, IGEs are a key element in the genetical theory of social evolution.",
    url = "https://doi.org/10.1111/j.1420-9101.2008.01550.x",
    doi = "10.1111/j.1420-9101.2008.01550.x",
    openalex = "W1985894030",
    references = "doi101534genetics106062711"
}

Biological evolution is a fact--but the many conflicting theories of evolution remain controversial even today. In 1966, simple Darwinism, which holds that evolution functions primarily at the level of the individual organism, was threatened by opposing concepts such as group selection, a popular idea stating that evolution acts to select entire species rather than individuals. George Williams's famous argument in favor of the Darwinists struck a powerful blow to those in opposing camps. His Adaptation and Natural Selection, now a classic of science literature, is a thorough and convincing essay in defense of Darwinism; its suggestions for developing effective principles for dealing with the evolution debate and its relevance to many fields outside biology ensure the timelessness of this critical work.

@book{doi1015159781400820108,
    author = "Williams, George C.",
    title = "Adaptation and Natural Selection",
    year = "2008",
    booktitle = "Princeton University Press eBooks",
    abstract = "Biological evolution is a fact--but the many conflicting theories of evolution remain controversial even today. In 1966, simple Darwinism, which holds that evolution functions primarily at the level of the individual organism, was threatened by opposing concepts such as group selection, a popular idea stating that evolution acts to select entire species rather than individuals. George Williams's famous argument in favor of the Darwinists struck a powerful blow to those in opposing camps. His Adaptation and Natural Selection, now a classic of science literature, is a thorough and convincing essay in defense of Darwinism; its suggestions for developing effective principles for dealing with the evolution debate and its relevance to many fields outside biology ensure the timelessness of this critical work.",
    url = "https://doi.org/10.1515/9781400820108",
    doi = "10.1515/9781400820108",
    openalex = "W2020289104"
}

@article{doi101016jjpolmod200807002,
    author = "Arce, Daniel G. and Sandler, Todd",
    title = "Fitting in: Group effects and the evolution of fundamentalism",
    year = "2009",
    journal = "Journal of Policy Modeling",
    url = "https://doi.org/10.1016/j.jpolmod.2008.07.002",
    doi = "10.1016/j.jpolmod.2008.07.002",
    openalex = "W2100437646",
    references = "cooper2004group, doi1010160160932782900369, doi101016s0003347276801108, doi101016s0024630197809661, doi101038227520a0, doi101038246015a0, doi101046j14390310199900372x, doi101093oepgpf064, doi101111j251761611951tb00088x, doi1023071906951, doi1023072069338"
}

Charles Darwin laid the foundation for all modern work on sexual selection in his seminal book The Descent of Man, and Selection in Relation to Sex. In this work, Darwin fleshed out the mechanism of sexual selection, a hypothesis that he had proposed in The Origin of Species. He went well beyond a simple description of the phenomenon by providing extensive evidence and considering the far-reaching implications of the idea. Here we consider the contributions of Darwin to sexual selection with a particular eye on how far we have progressed in the last 150 years. We focus on 2 key questions in sexual selection. First, why does mate choice evolve at all? And second, what factors determine the strength of mate choice (or intensity of sexual selection) in each sex? Darwin provided partial answers to these questions, and the progress that has been made on both of these topics since his time should be seen as one of the great triumphs of modern evolutionary biology. However, a review of the literature shows that key aspects of sexual selection are still plagued by confusion and disagreement. Many of these areas are complex and will require new theory and empirical data for complete resolution. Overall, Darwin's contributions are still surprisingly relevant to the modern study of sexual selection, so students of evolutionary biology would be well advised to revisit his works. Although we have made significant progress in some areas of sexual selection research, we still have much to accomplish.

@article{doi101073pnas0901129106,
    author = "Jones, Adam G. and Ratterman, Nicholas L.",
    title = "Mate choice and sexual selection: What have we learned since Darwin?",
    year = "2009",
    journal = "Proceedings of the National Academy of Sciences",
    abstract = "Charles Darwin laid the foundation for all modern work on sexual selection in his seminal book The Descent of Man, and Selection in Relation to Sex. In this work, Darwin fleshed out the mechanism of sexual selection, a hypothesis that he had proposed in The Origin of Species. He went well beyond a simple description of the phenomenon by providing extensive evidence and considering the far-reaching implications of the idea. Here we consider the contributions of Darwin to sexual selection with a particular eye on how far we have progressed in the last 150 years. We focus on 2 key questions in sexual selection. First, why does mate choice evolve at all? And second, what factors determine the strength of mate choice (or intensity of sexual selection) in each sex? Darwin provided partial answers to these questions, and the progress that has been made on both of these topics since his time should be seen as one of the great triumphs of modern evolutionary biology. However, a review of the literature shows that key aspects of sexual selection are still plagued by confusion and disagreement. Many of these areas are complex and will require new theory and empirical data for complete resolution. Overall, Darwin's contributions are still surprisingly relevant to the modern study of sexual selection, so students of evolutionary biology would be well advised to revisit his works. Although we have made significant progress in some areas of sexual selection research, we still have much to accomplish.",
    url = "https://doi.org/10.1073/pnas.0901129106",
    doi = "10.1073/pnas.0901129106",
    openalex = "W2134522520",
    references = "doi101016jtree200603015, doi101086303168, doi101111j15585646201001012x"
}

Abstract In 1859 Charles Darwin described a deceptively simple mechanism that he called "natural selection," a combination of variation, inheritance, and reproductive success. He argued that this mechanism was the key to explaining the most puzzling features of the natural world, and science and philosophy were changed forever as a result. The exact nature of the Darwinian process has been controversial ever since, however. The author draws on new developments in biology, philosophy of science, and other fields to give a new analysis and extension of Darwin's idea. The central concept used is that of a "Darwinian population," a collection of things with the capacity to undergo change by natural selection. From this starting point, new analyses of the role of genes in evolution, the application of Darwinian ideas to cultural change, and "evolutionary transitions" that produce complex organisms and societies are developed.

@book{doi101093acprofosobl97801995520470010001,
    author = "Godfrey‐Smith, Peter",
    title = "Darwinian Populations and Natural Selection",
    year = "2009",
    booktitle = "Oxford University Press eBooks",
    abstract = {Abstract In 1859 Charles Darwin described a deceptively simple mechanism that he called "natural selection," a combination of variation, inheritance, and reproductive success. He argued that this mechanism was the key to explaining the most puzzling features of the natural world, and science and philosophy were changed forever as a result. The exact nature of the Darwinian process has been controversial ever since, however. The author draws on new developments in biology, philosophy of science, and other fields to give a new analysis and extension of Darwin's idea. The central concept used is that of a "Darwinian population," a collection of things with the capacity to undergo change by natural selection. From this starting point, new analyses of the role of genes in evolution, the application of Darwinian ideas to cultural change, and "evolutionary transitions" that produce complex organisms and societies are developed.},
    url = "https://doi.org/10.1093/acprof:osobl/9780199552047.001.0001",
    doi = "10.1093/acprof:osobl/9780199552047.001.0001",
    openalex = "W4294373694"
}

Abstract Experimental approaches to evolution provide indisputable evidence of evolution by directly observing the process at work. Experimental evolution deliberately duplicates evolutionary processes—forcing life histories to evolve, producing adaptations to stressful environmental conditions, and generating lineage splitting to create incipient species. This book summarizes studies in experimental evolution, outlining current techniques and applications, and presenting the field's full range of research—from selection in the laboratory to the manipulation of populations in the wild. It provides work on such key biological problems as the evolution of Darwinian fitness, sexual reproduction, life history, athletic performance, and learning.

@book{doi101525california97805202476660010001,
    author = "Garland, Theodore and Rose, Michael R.",
    title = "Experimental EvolutionConcepts, Methods, and Applications of Selection Experiments",
    year = "2009",
    abstract = "Abstract Experimental approaches to evolution provide indisputable evidence of evolution by directly observing the process at work. Experimental evolution deliberately duplicates evolutionary processes—forcing life histories to evolve, producing adaptations to stressful environmental conditions, and generating lineage splitting to create incipient species. This book summarizes studies in experimental evolution, outlining current techniques and applications, and presenting the field's full range of research—from selection in the laboratory to the manipulation of populations in the wild. It provides work on such key biological problems as the evolution of Darwinian fitness, sexual reproduction, life history, athletic performance, and learning.",
    url = "https://doi.org/10.1525/california/9780520247666.001.0001",
    doi = "10.1525/california/9780520247666.001.0001",
    openalex = "W2491992902",
    references = "doi101086289977, doi101086341993, doi101146annurevph57030195000441"
}

In spite of recent interest in sexual selection in females, debate exists over whether traits that influence female-female competition are sexually selected. This review uses female-female aggressive behavior as a model behavioral trait for understanding the evolutionary mechanisms promoting intrasexual competition, focusing especially on sexual selection. I employ a broad definition of sexual selection, whereby traits that influence competition for mates are sexually selected, whereas those that directly influence fecundity or offspring survival are naturally selected. Drawing examples from across animal taxa, including humans, I examine 4 predictions about female intrasexual competition based on the abundance of resources, the availability of males, and the direct or indirect benefits those males provide. These patterns reveal a key sex difference in sexual selection: Although females may compete for the number of mates, they appear to compete more so for access to high-quality mates that provide direct and indirect (genetic) benefits. As is the case in males, intrasexual selection in females also includes competition for essential resources required for access to mates. If mate quality affects the magnitude of mating success, then restricting sexual selection to competition for quantity of mates may ignore important components of fitness in females and underestimate the role of sexual selection in shaping female phenotype. In the future, understanding sex differences in sexual selection will require further exploration of the extent of mutual intrasexual competition and the incorporation of quality of mating success into the study of sexual selection in both sexes.

@article{doi101093behecoarr106,
    author = "Rosvall, Kimberly A.",
    title = "Intrasexual competition in females: evidence for sexual selection?",
    year = "2011",
    journal = "Behavioral Ecology",
    abstract = "In spite of recent interest in sexual selection in females, debate exists over whether traits that influence female-female competition are sexually selected. This review uses female-female aggressive behavior as a model behavioral trait for understanding the evolutionary mechanisms promoting intrasexual competition, focusing especially on sexual selection. I employ a broad definition of sexual selection, whereby traits that influence competition for mates are sexually selected, whereas those that directly influence fecundity or offspring survival are naturally selected. Drawing examples from across animal taxa, including humans, I examine 4 predictions about female intrasexual competition based on the abundance of resources, the availability of males, and the direct or indirect benefits those males provide. These patterns reveal a key sex difference in sexual selection: Although females may compete for the number of mates, they appear to compete more so for access to high-quality mates that provide direct and indirect (genetic) benefits. As is the case in males, intrasexual selection in females also includes competition for essential resources required for access to mates. If mate quality affects the magnitude of mating success, then restricting sexual selection to competition for quantity of mates may ignore important components of fitness in females and underestimate the role of sexual selection in shaping female phenotype. In the future, understanding sex differences in sexual selection will require further exploration of the extent of mutual intrasexual competition and the incorporation of quality of mating success into the study of sexual selection in both sexes.",
    url = "https://doi.org/10.1093/beheco/arr106",
    doi = "10.1093/beheco/arr106",
    openalex = "W2154986968",
    references = "doi101016jtree200603015, doi101111j15585646201001012x, doi105962bhltitle19780"
}

Natural selection operates both directly, via the impact of a trait upon the individual's own fitness, and indirectly, via the impact of the trait upon the fitness of the individual's genetically related social partners. These effects are often framed in terms of Hamilton's rule, rb - c > 0, which provides the central result of social-evolution theory. However, a number of studies have questioned the generality of Hamilton's rule, suggesting that it requires restrictive assumptions. Here, we use Fisher's genetical paradigm to demonstrate the generality of Hamilton's rule and to clarify links between different studies. We show that confusion has arisen owing to researchers misidentifying model parameters with the b and c terms in Hamilton's rule, and misidentifying measures of genotypic similarity or genealogical relationship with the coefficient of genetic relatedness, r. More generally, we emphasize the need to distinguish between general kin-selection theory that forms the foundations of social evolution, and streamlined kin-selection methodology that is used to solve specific problems.

@article{doi101111j14209101201102236x,
    author = "Gardner, Andy and West, Stuart A. and Wild, Geoff",
    title = "The genetical theory of kin selection",
    year = "2011",
    journal = "Journal of Evolutionary Biology",
    abstract = "Natural selection operates both directly, via the impact of a trait upon the individual's own fitness, and indirectly, via the impact of the trait upon the fitness of the individual's genetically related social partners. These effects are often framed in terms of Hamilton's rule, rb - c > 0, which provides the central result of social-evolution theory. However, a number of studies have questioned the generality of Hamilton's rule, suggesting that it requires restrictive assumptions. Here, we use Fisher's genetical paradigm to demonstrate the generality of Hamilton's rule and to clarify links between different studies. We show that confusion has arisen owing to researchers misidentifying model parameters with the b and c terms in Hamilton's rule, and misidentifying measures of genotypic similarity or genealogical relationship with the coefficient of genetic relatedness, r. More generally, we emphasize the need to distinguish between general kin-selection theory that forms the foundations of social evolution, and streamlined kin-selection methodology that is used to solve specific problems.",
    url = "https://doi.org/10.1111/j.1420-9101.2011.02236.x",
    doi = "10.1111/j.1420-9101.2011.02236.x",
    openalex = "W1539514422",
    references = "doi101016jevolhumbehav201008001, doi101017cbo9780511542053, doi101086303168, doi101093acprofoso97801992679720010001, doi101111j14209101200801681x, doi101111j15585646201001012x, doi1015159781400832019"
}

Ornaments, weapons and aggressive behaviours may evolve in female animals by mate choice and intrasexual competition for mating opportunities-the standard forms of sexual selection in males. However, a growing body of evidence suggests that selection tends to operate in different ways in males and females, with female traits more often mediating competition for ecological resources, rather than mate acquisition. Two main solutions have been proposed to accommodate this disparity. One is to expand the concept of sexual selection to include all mechanisms related to fecundity; another is to adopt an alternative conceptual framework-the theory of social selection-in which sexual selection is one component of a more general form of selection resulting from all social interactions. In this study, we summarize the history of the debate about female ornaments and weapons, and discuss potential resolutions. We review the components of fitness driving ornamentation in a wide range of systems, and show that selection often falls outside the limits of traditional sexual selection theory, particularly in females. We conclude that the evolution of these traits in both sexes is best understood within the unifying framework of social selection.

@article{doi101098rstb20110280,
    author = "Tobias, Joseph A. and Montgomerie, Robert and Lyon, Bruce E.",
    title = "The evolution of female ornaments and weaponry: social selection, sexual selection and ecological competition",
    year = "2012",
    journal = "Philosophical Transactions of the Royal Society B Biological Sciences",
    abstract = "Ornaments, weapons and aggressive behaviours may evolve in female animals by mate choice and intrasexual competition for mating opportunities-the standard forms of sexual selection in males. However, a growing body of evidence suggests that selection tends to operate in different ways in males and females, with female traits more often mediating competition for ecological resources, rather than mate acquisition. Two main solutions have been proposed to accommodate this disparity. One is to expand the concept of sexual selection to include all mechanisms related to fecundity; another is to adopt an alternative conceptual framework-the theory of social selection-in which sexual selection is one component of a more general form of selection resulting from all social interactions. In this study, we summarize the history of the debate about female ornaments and weapons, and discuss potential resolutions. We review the components of fitness driving ornamentation in a wide range of systems, and show that selection often falls outside the limits of traditional sexual selection theory, particularly in females. We conclude that the evolution of these traits in both sexes is best understood within the unifying framework of social selection.",
    url = "https://doi.org/10.1098/rstb.2011.0280",
    doi = "10.1098/rstb.2011.0280",
    openalex = "W2109893252",
    references = "doi101007978140206287210, doi101086303168, doi101111j15585646201001012x, doi105962bhltitle17416"
}

We study the evolution of both characteristics of reciprocity: the willingness to reward and the willingness to punish. First, both preferences for rewarding and preferences for punishing can survive provided that individuals interact within separate groups. Second, rewarders survive only in coexistence with self-interested preferences, but punishers either vanish or dominate the population entirely. Third, the evolution of preferences for rewarding and the evolution of preferences for punishing influence each other decisively. Rewarders can invade a population of self-interested players. The existence of rewarders enhances the evolutionary success of punishers, who then crowd out all other preferences. (JEL C71, C72, C73, D64, K42)

@article{doi101257aer1022914,
    author = "Herold, Florian",
    title = "Carrot or Stick? The Evolution of Reciprocal Preferences in a Haystack Model",
    year = "2012",
    journal = "American Economic Review",
    abstract = "We study the evolution of both characteristics of reciprocity: the willingness to reward and the willingness to punish. First, both preferences for rewarding and preferences for punishing can survive provided that individuals interact within separate groups. Second, rewarders survive only in coexistence with self-interested preferences, but punishers either vanish or dominate the population entirely. Third, the evolution of preferences for rewarding and the evolution of preferences for punishing influence each other decisively. Rewarders can invade a population of self-interested players. The existence of rewarders enhances the evolutionary success of punishers, who then crowd out all other preferences. (JEL C71, C72, C73, D64, K42)",
    url = "https://doi.org/10.1257/aer.102.2.914",
    doi = "10.1257/aer.102.2.914",
    openalex = "W3125391255",
    references = "cooper2004group, doi1010382011145a0, doi101038227520a0, doi101046j14390310199900372x, doi101126science1133755, doi101257aer1022i, doi101257aer901166, doi101257aer91273, doi101257jep143159, doi1023071367778, doi1023072951777"
}

The profound benefits of altruism in modern society are self-evident. However, the potential hurtful aspects of altruism have gone largely unrecognized in scientific inquiry. This is despite the fact that virtually all forms of altruism are associated with tradeoffs—some of enormous importance and sensitivity—and notwithstanding that examples of pathologies of altruism abound. Presented here are the mechanistic bases and potential ramifications of pathological altruism, that is, altruism in which attempts to promote the welfare of others instead result in unanticipated harm. A basic conceptual approach toward the quantification of altruism bias is presented. Guardian systems and their over arching importance in the evolution of cooperation are also discussed. Concepts of pathological altruism, altruism bias, and guardian systems may help open many new, potentially useful lines of inquiry and provide a framework to begin moving toward a more mature, scientifically informed understanding of altruism and cooperative behavior.

@article{doi101073pnas1302547110,
    author = "Oakley, Barbara",
    title = "Concepts and implications of altruism bias and pathological altruism",
    year = "2013",
    journal = "Proceedings of the National Academy of Sciences",
    abstract = "The profound benefits of altruism in modern society are self-evident. However, the potential hurtful aspects of altruism have gone largely unrecognized in scientific inquiry. This is despite the fact that virtually all forms of altruism are associated with tradeoffs—some of enormous importance and sensitivity—and notwithstanding that examples of pathologies of altruism abound. Presented here are the mechanistic bases and potential ramifications of pathological altruism, that is, altruism in which attempts to promote the welfare of others instead result in unanticipated harm. A basic conceptual approach toward the quantification of altruism bias is presented. Guardian systems and their over arching importance in the evolution of cooperation are also discussed. Concepts of pathological altruism, altruism bias, and guardian systems may help open many new, potentially useful lines of inquiry and provide a framework to begin moving toward a more mature, scientifically informed understanding of altruism and cooperative behavior.",
    url = "https://doi.org/10.1073/pnas.1302547110",
    doi = "10.1073/pnas.1302547110",
    openalex = "W1984037841",
    references = "doi101073pnas751385"
}

Many of the most important properties of human groups - including properties that may give one group an evolutionary advantage over another - are properly defined only at the level of group organization. Yet at present, most work on the evolution of culture has focused solely on the transmission of individual-level traits. I propose a conceptual extension of the theory of cultural evolution, particularly related to the evolutionary competition between cultural groups. The key concept in this extension is the emergent group-level trait. This type of trait is characterized by the structured organization of differentiated individuals and constitutes a unit of selection that is qualitatively different from selection on groups as defined by traditional multilevel selection (MLS) theory. As a corollary, I argue that the traditional focus on cooperation as the defining feature of human societies has missed an essential feature of cooperative groups. Traditional models of cooperation assume that interacting with one cooperator is equivalent to interacting with any other. However, human groups involve differential roles, meaning that receiving aid from one individual is often preferred to receiving aid from another. In this target article, I discuss the emergence and evolution of group-level traits and the implications for the theory of cultural evolution, including ramifications for the evolution of human cooperation, technology, and cultural institutions, and for the equivalency of multilevel selection and inclusive fitness approaches.

@article{doi101017s0140525x13001544,
    author = "Smaldino, Paul E.",
    title = "The cultural evolution of emergent group-level traits",
    year = "2014",
    journal = "Behavioral and Brain Sciences",
    abstract = "Many of the most important properties of human groups - including properties that may give one group an evolutionary advantage over another - are properly defined only at the level of group organization. Yet at present, most work on the evolution of culture has focused solely on the transmission of individual-level traits. I propose a conceptual extension of the theory of cultural evolution, particularly related to the evolutionary competition between cultural groups. The key concept in this extension is the emergent group-level trait. This type of trait is characterized by the structured organization of differentiated individuals and constitutes a unit of selection that is qualitatively different from selection on groups as defined by traditional multilevel selection (MLS) theory. As a corollary, I argue that the traditional focus on cooperation as the defining feature of human societies has missed an essential feature of cooperative groups. Traditional models of cooperation assume that interacting with one cooperator is equivalent to interacting with any other. However, human groups involve differential roles, meaning that receiving aid from one individual is often preferred to receiving aid from another. In this target article, I discuss the emergence and evolution of group-level traits and the implications for the theory of cultural evolution, including ramifications for the evolution of human cooperation, technology, and cultural institutions, and for the equivalency of multilevel selection and inclusive fitness approaches.",
    url = "https://doi.org/10.1017/s0140525x13001544",
    doi = "10.1017/s0140525x13001544",
    openalex = "W2108786427",
    references = "doi10103831383, doi101086289977, doi101371journalpbio0020439"
}

Human cooperation is highly unusual. We live in large groups composed mostly of non-relatives. Evolutionists have proposed a number of explanations for this pattern, including cultural group selection and extensions of more general processes such as reciprocity, kin selection, and multi-level selection acting on genes. Evolutionary processes are consilient; they affect several different empirical domains, such as patterns of behavior and the proximal drivers of that behavior. In this target article, we sketch the evidence from five domains that bear on the explanatory adequacy of cultural group selection and competing hypotheses to explain human cooperation. Does cultural transmission constitute an inheritance system that can evolve in a Darwinian fashion? Are the norms that underpin institutions among the cultural traits so transmitted? Do we observe sufficient variation at the level of groups of considerable size for group selection to be a plausible process? Do human groups compete, and do success and failure in competition depend upon cultural variation? Do we observe adaptations for cooperation in humans that most plausibly arose by cultural group selection? If the answer to one of these questions is "no," then we must look to other hypotheses. We present evidence, including quantitative evidence, that the answer to all of the questions is "yes" and argue that we must take the cultural group selection hypothesis seriously. If culturally transmitted systems of rules (institutions) that limit individual deviance organize cooperation in human societies, then it is not clear that any extant alternative to cultural group selection can be a complete explanation.

@article{doi101017s0140525x1400106x,
    author = "Richerson, Peter J. and Baldini, Ryan and Bell, Adrian V. and Demps, Kathryn and Frost, Karl and Hillis, Vicken and Mathew, Sarah and Newton, Emily K. and Naar, Nicole and Newson, Lesley and Ross, Cody T. and Smaldino, Paul E. and Waring, Timothy M. and Zefferman, Matthew",
    title = "Cultural group selection plays an essential role in explaining human cooperation: A sketch of the evidence",
    year = "2014",
    journal = "Behavioral and Brain Sciences",
    abstract = {Human cooperation is highly unusual. We live in large groups composed mostly of non-relatives. Evolutionists have proposed a number of explanations for this pattern, including cultural group selection and extensions of more general processes such as reciprocity, kin selection, and multi-level selection acting on genes. Evolutionary processes are consilient; they affect several different empirical domains, such as patterns of behavior and the proximal drivers of that behavior. In this target article, we sketch the evidence from five domains that bear on the explanatory adequacy of cultural group selection and competing hypotheses to explain human cooperation. Does cultural transmission constitute an inheritance system that can evolve in a Darwinian fashion? Are the norms that underpin institutions among the cultural traits so transmitted? Do we observe sufficient variation at the level of groups of considerable size for group selection to be a plausible process? Do human groups compete, and do success and failure in competition depend upon cultural variation? Do we observe adaptations for cooperation in humans that most plausibly arose by cultural group selection? If the answer to one of these questions is "no," then we must look to other hypotheses. We present evidence, including quantitative evidence, that the answer to all of the questions is "yes" and argue that we must take the cultural group selection hypothesis seriously. If culturally transmitted systems of rules (institutions) that limit individual deviance organize cooperation in human societies, then it is not clear that any extant alternative to cultural group selection can be a complete explanation.},
    url = "https://doi.org/10.1017/s0140525x1400106x",
    doi = "10.1017/s0140525x1400106x",
    openalex = "W2155058526",
    references = "doi101007978140206287210, doi101016jevolhumbehav201008001, doi101016jjhevol201007011, doi101017cbo9780511807763, doi101017s0140525x0999094x, doi101017s0140525x14000090, doi101017s0140525x14001356, doi1010370033295x982224, doi101073pnas0904312106, doi101086303168, doi101086668207, doi101093oxfordjournalscjea013725, doi101098rspb20091650, doi101098rspb20151019, doi101098rstb20090052, doi101111j14677687200700573x, doi101257aer10052060, doi101257aer991431, doi101371journalpone0045150, doi101537ase188722495, doi1023071367778, doi1023072232409, doi1023073146384, doi105860choice416654, doi105860choice485062, openalexw1581387623, openalexw2034328075, openalexw2624262714, openalexw3124182182"
}

Mathematical biologists have failed to produce a satisfactory general model for evolution of altruism, i.e., of behaviors by which altruists benefit other individuals but not themselves; kin selection does not seem to be a sufficient explanation of nonreciprocal altruism. Nonmathematical (but mathematically accept- able) models are now proposed for evolution of negative in dual-determinant and of positive in tri-determinant systems. Peck orders, territorial systems, and an ant society are analyzed as examples. In all models, evolution is primarily by individual selection, probably supplemented by group selection. Group selection is differential extinction of populations. It can act only on populations preformed by selection at the individual level, but can either cancel individual selective trends (effecting evolutionary homeostasis) or supplement them; its supple- mentary effect is probably increasingly important in the evolution of increasingly organized populations. Biological altruism, broadly defined, includes all behaviors by which some individuals benefit others of the same species, without benefiting themselves. The benefits may be voluntary or involuntary and direct or indirect: e.g., genetic shortening of life spans is if it prevents older individuals fromi competing to the disadvantage of younger ones. (But re- ciprocal altruism (1) is not by this definition, be- cause probabilities of benefits are mutual.) More broadly, is concerned with the relation of individuals to the populations they belong to, and is involved in the organiza- tion and evolution of social systems of insects and other animals and, of course, of men. The extent to which occurs in nonhuman, as well as in human, populations, and how it does or may evolve, are therefore important questions,

@article{openalexw2406557622,
    author = "Darlington, P. J.",
    title = "Nonmathematical Models for Evolution of (peck order/territoriality/ant colony/dual-determinant n",
    year = "2016",
    abstract = "Mathematical biologists have failed to produce a satisfactory general model for evolution of altruism, i.e., of behaviors by which altruists benefit other individuals but not themselves; kin selection does not seem to be a sufficient explanation of nonreciprocal altruism. Nonmathematical (but mathematically accept- able) models are now proposed for evolution of negative in dual-determinant and of positive in tri-determinant systems. Peck orders, territorial systems, and an ant society are analyzed as examples. In all models, evolution is primarily by individual selection, probably supplemented by group selection. Group selection is differential extinction of populations. It can act only on populations preformed by selection at the individual level, but can either cancel individual selective trends (effecting evolutionary homeostasis) or supplement them; its supple- mentary effect is probably increasingly important in the evolution of increasingly organized populations. Biological altruism, broadly defined, includes all behaviors by which some individuals benefit others of the same species, without benefiting themselves. The benefits may be voluntary or involuntary and direct or indirect: e.g., genetic shortening of life spans is if it prevents older individuals fromi competing to the disadvantage of younger ones. (But re- ciprocal altruism (1) is not by this definition, be- cause probabilities of benefits are mutual.) More broadly, is concerned with the relation of individuals to the populations they belong to, and is involved in the organiza- tion and evolution of social systems of insects and other animals and, of course, of men. The extent to which occurs in nonhuman, as well as in human, populations, and how it does or may evolve, are therefore important questions,",
    url = "https://openalex.org/W2406557622",
    openalex = "W2406557622",
    references = "doi105281zenodo10742832, openalexw1725516486, openalexw2616504082"
}

Just over one hundred and thirty years ago Charles Darwin, in The Descent of Man and Selection in Relation to Sex (1871), developed remarkably accurate conclusions about man's ancestry, based on a review of general comparative anatomy and psychology in which he regarded sexual selection as a necessary part of the evolutionary process. But the attention of biologists turned to the more general concept of natural selection, in which sexual selection plays a complex role that has been little understood. This volume significantly broadens the scope of modern evolutionary biology by looking at this important and long neglected concept of great importance. In this book, which is the first full discussion of sexual selection since 1871, leading biologists bring modern genetic theory and behavior observation to bear on the subject. The distinguished authors consider many aspects of sexual selection in many species, including man, within the context of contemporary evolutionary theory and research. The result is a remarkably original and well-rounded view of the whole concept that will be invaluable especially to students of evolution and human sexual behavior. The lucid authority of the contributors and the importance of the topic will interest all who share in man's perennial fascination with his own history. The book will be of central importance to a wide variety of professionals, including biologists, anthropologists, and geneticists. It will be an invaluable supplementary text for courses in vertebrate biology, theory of evolution, genetics, and physical anthropology. It is especially important with the emergence of alternative explanations of human development, under the rubric of creationism and doctrines of intelligent design.

@book{doi1043249781315129266,
    title = "Sexual Selection and the Descent of Man",
    year = "2017",
    abstract = "Just over one hundred and thirty years ago Charles Darwin, in The Descent of Man and Selection in Relation to Sex (1871), developed remarkably accurate conclusions about man's ancestry, based on a review of general comparative anatomy and psychology in which he regarded sexual selection as a necessary part of the evolutionary process. But the attention of biologists turned to the more general concept of natural selection, in which sexual selection plays a complex role that has been little understood. This volume significantly broadens the scope of modern evolutionary biology by looking at this important and long neglected concept of great importance. In this book, which is the first full discussion of sexual selection since 1871, leading biologists bring modern genetic theory and behavior observation to bear on the subject. The distinguished authors consider many aspects of sexual selection in many species, including man, within the context of contemporary evolutionary theory and research. The result is a remarkably original and well-rounded view of the whole concept that will be invaluable especially to students of evolution and human sexual behavior. The lucid authority of the contributors and the importance of the topic will interest all who share in man's perennial fascination with his own history. The book will be of central importance to a wide variety of professionals, including biologists, anthropologists, and geneticists. It will be an invaluable supplementary text for courses in vertebrate biology, theory of evolution, genetics, and physical anthropology. It is especially important with the emergence of alternative explanations of human development, under the rubric of creationism and doctrines of intelligent design.",
    url = "https://doi.org/10.4324/9781315129266",
    doi = "10.4324/9781315129266",
    openalex = "W2146850492",
    references = "doi1010079789401165273, doi1010160022519364900384, doi101016s0066185668800032, doi101086282628, doi101086282637, doi101111j1469185x1970tb01176x, doi101111j155856461970tb01740x, doi1015159781400820108, doi101537ase188722495, doi105962bhltitle27468"
}

Biological evolution is a fact-but the many conflicting theories of evolution remain controversial even today. When Adaptation and Natural Selection was first published in 1966, it struck a powerful blow against those who argued for the concept of group selection-the idea that evolution acts to select entire species rather than individuals. Williams's famous work in favor of simple Darwinism over group selection has become a classic of science literature, valued for its thorough and convincing argument and its relevance to many fields outside of biology. Now with a new foreword by Richard Dawkins, Adaptation and Natural Selection is an essential text for understanding the nature of scientific debate

@book{doi1015159780691185507,
    author = "Williams, George C.",
    title = "Adaptation and Natural Selection: A Critique of Some Current Evolutionary Thought",
    year = "2018",
    abstract = "Biological evolution is a fact-but the many conflicting theories of evolution remain controversial even today. When Adaptation and Natural Selection was first published in 1966, it struck a powerful blow against those who argued for the concept of group selection-the idea that evolution acts to select entire species rather than individuals. Williams's famous work in favor of simple Darwinism over group selection has become a classic of science literature, valued for its thorough and convincing argument and its relevance to many fields outside of biology. Now with a new foreword by Richard Dawkins, Adaptation and Natural Selection is an essential text for understanding the nature of scientific debate",
    url = "https://doi.org/10.1515/9780691185507",
    doi = "10.1515/9780691185507",
    openalex = "W1480083809"
}

Sex-Ratio (SR) chromosomes are selfish X -chromosomes that distort Mendelian segregation and are commonly associated with inversions. These chromosomal rearrangements suppress recombination with Standard (ST) X -chromosomes and are hypothesized to maintain multiple alleles important for distortion in a single large haplotype. Here, we conduct a multifaceted study of the multiply inverted Drosophila p se udoobscura SR chromosome to understand the evolutionary history, genetic architecture, and present-day dynamics that shape this enigmatic selfish chromosome. The D. p se udoobscura SR chromosome has three nonoverlapping inversions of the right arm of the metacentric X -chromosome: basal, medial, and terminal. We find that 23 of 29 Mb of the D. p se udoobscura X -chromosome right arm is highly differentiated between the Standard and SR arrangements, including a 6.6 Mb collinear region between the medial and terminal inversions. Although crossing-over is heavily suppressed on this chromosome arm, we discover it is not completely eliminated, with measured rates indicating recombination suppression alone cannot explain patterns of differentiation or the near-perfect association of the three SR chromosome inversions in nature. We then demonstrate the ancient basal and medial inversions of the SR chromosome contain genes sufficient to cause weak distortion. In contrast, the younger terminal inversion cannot distort by itself, but contains at least one modifier gene necessary for full manifestation of strong sex chromosome distortion. By parameterizing population genetic models for chromosome-wide linkage disequilibrium with our experimental results, we infer that strong selection acts to maintain the near-perfect association of SR chromosome inversions in present-day populations. Based on comparative genomic analyses, direct recombination experiments, segregation distortion assays, and population genetic modeling, we conclude the combined action of suppressed recombination and strong, ongoing, epistatic selection shape the D. p se udoobscura SR arrangement into a highly differentiated chromosome.

@article{doi101534genetics120303460,
    author = "Fuller, Zachary L. and Koury, Spencer and Leonard, Christopher J. and Young, Randee E. and Ikegami, Kobe and Westlake, Jonathan and Richards, Stephen and Schaeffer, Stephen W. and Phadnis, Nitin",
    title = "Extensive Recombination Suppression and Epistatic Selection Causes Chromosome-Wide Differentiation of a Selfish Sex Chromosome in Drosophila pseudoobscura",
    year = "2020",
    journal = "Genetics",
    abstract = "Sex-Ratio (SR) chromosomes are selfish X -chromosomes that distort Mendelian segregation and are commonly associated with inversions. These chromosomal rearrangements suppress recombination with Standard (ST) X -chromosomes and are hypothesized to maintain multiple alleles important for distortion in a single large haplotype. Here, we conduct a multifaceted study of the multiply inverted Drosophila p se udoobscura SR chromosome to understand the evolutionary history, genetic architecture, and present-day dynamics that shape this enigmatic selfish chromosome. The D. p se udoobscura SR chromosome has three nonoverlapping inversions of the right arm of the metacentric X -chromosome: basal, medial, and terminal. We find that 23 of 29 Mb of the D. p se udoobscura X -chromosome right arm is highly differentiated between the Standard and SR arrangements, including a 6.6 Mb collinear region between the medial and terminal inversions. Although crossing-over is heavily suppressed on this chromosome arm, we discover it is not completely eliminated, with measured rates indicating recombination suppression alone cannot explain patterns of differentiation or the near-perfect association of the three SR chromosome inversions in nature. We then demonstrate the ancient basal and medial inversions of the SR chromosome contain genes sufficient to cause weak distortion. In contrast, the younger terminal inversion cannot distort by itself, but contains at least one modifier gene necessary for full manifestation of strong sex chromosome distortion. By parameterizing population genetic models for chromosome-wide linkage disequilibrium with our experimental results, we infer that strong selection acts to maintain the near-perfect association of SR chromosome inversions in present-day populations. Based on comparative genomic analyses, direct recombination experiments, segregation distortion assays, and population genetic modeling, we conclude the combined action of suppressed recombination and strong, ongoing, epistatic selection shape the D. p se udoobscura SR arrangement into a highly differentiated chromosome.",
    url = "https://doi.org/10.1534/genetics.120.303460",
    doi = "10.1534/genetics.120.303460",
    openalex = "W3046327068",
    references = "doi101086282886"
}

In this minireview, we address the trade-off between biological altruism (group adaptation result-ing from the ability of an organism to improve the fitness of an associate at the expense of its own fitness) and symbiogenesis — the evolutionary pathway based on genetic integration of non-related species. We address symbiogenesis as a multi-stage process, which involves for-mation of superspecific hereditary systems — functionally integral symbiogenomes (under the facultative partners’ interactions) reorganized into the structurally integral hologenomes (in the obligatory symbioses). The best studied case of symbiogenesis is represented by the evolution of the eukaryotic cell based on transformation of symbiotic bacteria into cellular organelles. This evolution is associated with the deep reduction of microsymbionts’ genomes and with allocation of their genes into the hosts. As a result, microsymbionts lost their Genetic INdividuality (GIN), characterized by an ability to implement DNA- and RNA-based template syntheses required for genome maintenance and expression. Under facultative symbiotic dependence on hosts, the par-tial loss of GIN is due to a “symbiont → host” altruism which in the N2-fixing microbe–plant symbioses results in formation of non-reproducible bacterial forms (e.g., intracellular bacteroids in rhizobia or multiple heterocysts in Nostoc). If micro-symbionts lose their ability of autonomous existence (e.g., in the vertically transmitted intracellular symbionts), they are switched to the “forced altruism” in which the GIN reduction is required for the stable persistence of symbionts in hosts. Therefore, organellogenesis involves the sequential increase of the symbionts’ de-pendency on hosts: conditional → facultative → obligatory → absolute. It is associated with the reorganization of microbes into semi-autonomous cellular components, which may be completely devoid of their own genomes.

@article{doi1021638spbu032021108,
    author = "Проворов, Н. А.",
    title = "Genetic individuality and interspecies altruism: modelling symbiogenesis using different types of symbiotic bacteria",
    year = "2021",
    journal = "Biological Communications",
    abstract = "In this minireview, we address the trade-off between biological altruism (group adaptation result-ing from the ability of an organism to improve the fitness of an associate at the expense of its own fitness) and symbiogenesis — the evolutionary pathway based on genetic integration of non-related species. We address symbiogenesis as a multi-stage process, which involves for-mation of superspecific hereditary systems — functionally integral symbiogenomes (under the facultative partners’ interactions) reorganized into the structurally integral hologenomes (in the obligatory symbioses). The best studied case of symbiogenesis is represented by the evolution of the eukaryotic cell based on transformation of symbiotic bacteria into cellular organelles. This evolution is associated with the deep reduction of microsymbionts’ genomes and with allocation of their genes into the hosts. As a result, microsymbionts lost their Genetic INdividuality (GIN), characterized by an ability to implement DNA- and RNA-based template syntheses required for genome maintenance and expression. Under facultative symbiotic dependence on hosts, the par-tial loss of GIN is due to a “symbiont → host” altruism which in the N2-fixing microbe–plant symbioses results in formation of non-reproducible bacterial forms (e.g., intracellular bacteroids in rhizobia or multiple heterocysts in Nostoc). If micro-symbionts lose their ability of autonomous existence (e.g., in the vertically transmitted intracellular symbionts), they are switched to the “forced altruism” in which the GIN reduction is required for the stable persistence of symbionts in hosts. Therefore, organellogenesis involves the sequential increase of the symbionts’ de-pendency on hosts: conditional → facultative → obligatory → absolute. It is associated with the reorganization of microbes into semi-autonomous cellular components, which may be completely devoid of their own genomes.",
    url = "https://doi.org/10.21638/spbu03.2021.108",
    doi = "10.21638/spbu03.2021.108",
    openalex = "W3144068874",
    references = "doi101073pnas751385"
}

Although nearly a century has elapsed since Darwin and Wallace formulated the theory of evolution by natural selection, it is remarkable that no agreement exists as to how it should be measured. Ideally we should wish to follow a sufficient number of members of every genotype (including gametes) of a species through a life cycle, and discover what advantages or disadvantages each possesses at every stage. This is clearly impossible. But it would also be insufficient. For natural or artificial selection acts on phenotypes. It is ineffective unless it favours one genotype at the expense of another. But it may occur without doing so. If we only breed from the heaviest 1% of members of a pure line, this intense artificial selection has no effect on the distribution of weights in the next generation. Nor would natural selection of comparable intensity have any effect. This is indeed the usual criterion for a pure line, though it may break down if there are strong maternal influences.

@incollection{doi104324978131576869414,
    author = "Haldane, J. B. S.",
    title = "The Measurement of Natural Selection",
    year = "2022",
    abstract = "Although nearly a century has elapsed since Darwin and Wallace formulated the theory of evolution by natural selection, it is remarkable that no agreement exists as to how it should be measured. Ideally we should wish to follow a sufficient number of members of every genotype (including gametes) of a species through a life cycle, and discover what advantages or disadvantages each possesses at every stage. This is clearly impossible. But it would also be insufficient. For natural or artificial selection acts on phenotypes. It is ineffective unless it favours one genotype at the expense of another. But it may occur without doing so. If we only breed from the heaviest 1\% of members of a pure line, this intense artificial selection has no effect on the distribution of weights in the next generation. Nor would natural selection of comparable intensity have any effect. This is indeed the usual criterion for a pure line, though it may break down if there are strong maternal influences.",
    url = "https://doi.org/10.4324/9781315768694-14",
    doi = "10.4324/9781315768694-14",
    openalex = "W4404725860"
}

Abstract This paper defends global realism about the units of selection, the view that there is always (or nearly always) an objective fact of the matter concerning the level at which natural selection acts. The argument proceeds in two stages. First, it is argued that global conventionalist-pluralism is false. This is established by identifying plausible sufficient conditions for irreducible selection at a particular level, and showing that these conditions are sometimes satisfied in nature. Second, it is argued that local pluralism – the view that while realism is true of some selection regimes, pluralist conventionalism holds for others – should also be rejected. I show that the main arguments for local pluralism are consistent with global realism. I also suggest that local pluralism offers an unacceptably disunified view of the metaphysics of selection. It follows that we should accept global realism. But this leaves open the question of how to classify so called ‘multi-level selection type 1’ (MLS1) processes, such as Wilson’s classic trait-group model for the evolution of altruism: should they be interpreted as particle selection or collective selection? On the assumption of global realism, at most one of these is correct. I argue, against global realists such as Sober, that MLS1 processes should be understood as particle, not collective, selection, due to three features of MLS1: the reducibility of collective fitness, the absence of collective reproduction, and the dispensable role of collectives.

@article{doi101007s1053902309931z,
    author = "Boucher, Sandy C.",
    title = "An argument for global realism about the units of selection",
    year = "2023",
    journal = "Biology \& Philosophy",
    abstract = "Abstract This paper defends global realism about the units of selection, the view that there is always (or nearly always) an objective fact of the matter concerning the level at which natural selection acts. The argument proceeds in two stages. First, it is argued that global conventionalist-pluralism is false. This is established by identifying plausible sufficient conditions for irreducible selection at a particular level, and showing that these conditions are sometimes satisfied in nature. Second, it is argued that local pluralism – the view that while realism is true of some selection regimes, pluralist conventionalism holds for others – should also be rejected. I show that the main arguments for local pluralism are consistent with global realism. I also suggest that local pluralism offers an unacceptably disunified view of the metaphysics of selection. It follows that we should accept global realism. But this leaves open the question of how to classify so called ‘multi-level selection type 1’ (MLS1) processes, such as Wilson’s classic trait-group model for the evolution of altruism: should they be interpreted as particle selection or collective selection? On the assumption of global realism, at most one of these is correct. I argue, against global realists such as Sober, that MLS1 processes should be understood as particle, not collective, selection, due to three features of MLS1: the reducibility of collective fitness, the absence of collective reproduction, and the dispensable role of collectives.",
    url = "https://doi.org/10.1007/s10539-023-09931-z",
    doi = "10.1007/s10539-023-09931-z",
    openalex = "W4387014143",
    references = "barrett2002group, doi1010800258013620191706384, doi101093acprofoso97801992679720010001, doi101093acprofosobl97801995520470010001, doi101146annureves01110170000245, doi1015159780691185507, doi1023072185056, doi1023072186103, doi1023072410462, doi105860choice366578, doi107208chicago97802261786530010001, openalexw1541831804"
}

Abstract The formalism used to describe evolutionary change in a multilevel setting can be used equally to re-describe the situation as one where all the selection occurs at the individual level. Thus, whether multilevel or individual-level selection occurs seems to be a matter of convention rather than fact. Yet, group selection is regarded by some as an important concept with factual rather than conventional elements. I flesh out an alternative position that regards groups as a target of selection in a way that is not merely definitional fiat and provide a theoretical basis for this position.

@article{doi101007s10670023007495,
    author = "Bourrat, Pierrick",
    title = "Moving Past Conventionalism About Multilevel Selection",
    year = "2023",
    journal = "Erkenntnis",
    abstract = "Abstract The formalism used to describe evolutionary change in a multilevel setting can be used equally to re-describe the situation as one where all the selection occurs at the individual level. Thus, whether multilevel or individual-level selection occurs seems to be a matter of convention rather than fact. Yet, group selection is regarded by some as an important concept with factual rather than conventional elements. I flesh out an alternative position that regards groups as a target of selection in a way that is not merely definitional fiat and provide a theoretical basis for this position.",
    url = "https://doi.org/10.1007/s10670-023-00749-5",
    doi = "10.1007/s10670-023-00749-5",
    openalex = "W4389388826",
    references = "doi1023072026633"
}

This narrative review aims to contribute to the scientific literature on awe by reviewing seven perspectives on the evolutionary function of awe. Each is presented with accompanying empirical evidence and suggestions for research investigating unanswered questions. Based on the existing perspectives, this review proposes an integrated evolutionary model of awe, postulating the evolutionary selection of awe through three adaptive domains: (1) social cooperation, (2) reflective processing, and (3) signaling suitability as a potential mate.

@article{doi10117717540739231197199,
    author = "Lucht, Antonia and van Schie, Hein T.",
    title = "The Evolutionary Function of Awe: A Review and Integrated Model of Seven Theoretical Perspectives",
    year = "2023",
    journal = "Emotion Review",
    abstract = "This narrative review aims to contribute to the scientific literature on awe by reviewing seven perspectives on the evolutionary function of awe. Each is presented with accompanying empirical evidence and suggestions for research investigating unanswered questions. Based on the existing perspectives, this review proposes an integrated evolutionary model of awe, postulating the evolutionary selection of awe through three adaptive domains: (1) social cooperation, (2) reflective processing, and (3) signaling suitability as a potential mate.",
    url = "https://doi.org/10.1177/17540739231197199",
    doi = "10.1177/17540739231197199",
    openalex = "W4386294224",
    references = "cooper2004group, doi101017cbo9780511620539, doi101037002235146761049, doi101037h0054346, doi10108002699930302297, doi101126science164387586, doi101146annurevpsych59103006093629, openalexw1555328317, openalexw1575922411, openalexw2600536710, openalexw2908473373"
}