View source for Group selection

{{Short description|Proposed mechanism of evolution}}
{{Good article}}
[[File:Archibald Thorburn Blackcocks at the Lek 1901.jpg|thumb|upright=1.3|Early explanations of [[social behaviour]], such as the [[lekking]] of [[blackcock]], spoke of "the good of the species".<ref name="Tudge2011"/> ''Blackcocks at the Lek'' [[watercolour]] and bodycolour by [[Archibald Thorburn]], 1901.|alt=image of lekking blackcock, an instance of social behaviour]]
'''Group selection''' is a proposed mechanism of [[evolution]] in which [[natural selection]] acts at the level of the group, instead of at the level of the individual or gene.

Early authors such as [[V. C. Wynne-Edwards]] and [[Konrad Lorenz]] argued that the [[Ethology|behaviour of animals]] could affect their survival and reproduction as groups, speaking for instance of actions for the good of the species. In the 1930s, [[Ronald Fisher]] and [[J. B. S. Haldane]] proposed the concept of [[kin selection]], a form of [[Altruism (biology)|biological altruism]] from the [[gene-centered view of evolution]], arguing that animals should sacrifice for their relatives, and thereby implying that they should not sacrifice for non-relatives. From the mid-1960s, [[evolutionary biologists]] such as [[John Maynard Smith]], [[W. D. Hamilton]], [[George Christopher Williams|George C. Williams]], and [[Richard Dawkins]] argued that [[natural selection]] acts primarily at the level of the gene. They argued on the basis of mathematical models that individuals would not altruistically sacrifice [[fitness (biology)|fitness]] for the sake of a group unless it would ultimately increase the likelihood of an individual passing on their genes. A consensus emerged that group selection did not occur, including in special situations such as the [[haplodiploid]] social insects like [[honeybees]] (in the [[Hymenoptera]]), where kin selection explains the behaviour of non-reproductives equally well, since the only way for them to reproduce their genes is via kin.<ref name="response to Nowak"/>

In 1994 [[David Sloan Wilson]] and [[Elliott Sober]] argued for multi-level selection, including group selection, on the grounds that groups, like individuals, could compete. In 2010 three authors including [[E. O. Wilson]], known for his work on [[social insects]] especially [[ant]]s, again revisited the arguments for group selection.<ref name="Nowak Tarnita Wilson 2010">{{Cite journal |last1=Nowak |first1=Martin A. |author1-link=Martin Nowak |last2=Tarnita |first2=Corina E. |author2-link=Corina Tarnita |last3=Wilson |first3=Edward O. |author3-link=Edward O. Wilson |date=August 2010 |title=The evolution of eusociality |journal=Nature |volume=466 |issue=7310 |pages=1057–1062 |doi=10.1038/nature09205 |pmid=20740005 |issn=1476-4687|pmc=3279739 |bibcode=2010Natur.466.1057N }}</ref> They argued that group selection can occur when competition between two or more groups, some containing altruistic individuals who act cooperatively together, is more important for survival than competition between individuals within each group.<ref name="Nowak Tarnita Wilson 2010"/> A large group of [[Ethology|ethologists]] conceded that while inclusive fitness may be debatable, it was still a useful theory in practice.<ref name=" response to Nowak"/><!--please DO NOT add anything here, this is a SUMMARY of the article not the place for new stuff, THANKS--> However, the vast majority of behavioural biologists have not been convinced by renewed attempts to revisit group selection as a plausible mechanism of evolution.<ref name="Rubinstein 2019">{{cite book |last1=Rubenstein |first1=Dustin R. |last2=Alcock |first2=John |title=Animal behavior |date=2019 |edition=Eleventh |location=Sunderland, Massachusetts |page=449 |chapter=12. Principles of Social Evolution |isbn=978-1-60535-548-1 |oclc=1022077347 |quote=there have been numerous attempts since Wynne-Edwards to develop more convincing forms of group selection theory. Indeed, this 'levels of selection' debate over the level of the biological hierarchy at which natural selection acts (individual, group, gene, species, community, and so forth) has generated much debate among behavioral biologists (Okasha 2010). Yet despite generating controversy, these attempts have generally failed to persuade the vast majority of behavioral biologists that Darwin's view of individual selection—even on altruistic traits that provide clear benefits to others—is wrong.}}</ref>

==Background==

{{Further|natural selection|kin selection}}

[[Charles Darwin]] developed the [[theory of evolution]] in his book, ''[[Origin of Species]]''. Darwin also made the first suggestion of group selection in ''[[The Descent of Man]]'' that the evolution of groups could affect the survival of individuals. He wrote, "If one man in a tribe... invented a new snare or weapon, the tribe would increase in number, spread, and supplant other tribes. In a tribe thus rendered more numerous there would always be a rather better chance of the birth of other superior and inventive members."<ref name="DOM">{{cite book |last=Darwin |first=Charles |author-link=Charles Darwin |title=The Descent of Man |url=https://archive.org/details/descentman00darwgoog |date=1871 |publisher=D. Appleton and Co. }}</ref><ref name="EOWilson-Social">{{cite book |last=Wilson |first=E. O. |author-link=E. O. Wilson |title=The Social Conquest of Earth |date=2013 |publisher=[[W. W. Norton & Company]] |location=New York}}</ref>

Once [[Darwinism]] had been accepted in the [[modern synthesis (20th century)|modern synthesis]] of the mid-twentieth century, animal behaviour was glibly explained with unsubstantiated hypotheses about survival value, which was largely taken for granted. The [[naturalist]] [[Konrad Lorenz]] had argued loosely in books like ''[[On Aggression]]'' (1966) that animal behaviour patterns were "for the good of the species",<ref name="Tudge2011">{{cite book |last=Tudge |first=Colin |title=Engineer In The Garden |url=https://books.google.com/books?id=Wprqex2OGY4C&pg=PT115 |date=31 March 2011 |publisher=[[Random House]] |isbn=978-1-4464-6698-8 |page=115}}</ref><ref name="Burkhardt2005">{{cite book |last=Burkhardt |first=Richard W. |title=Patterns of Behavior: Konrad Lorenz, Niko Tinbergen, and the Founding of Ethology |url=https://books.google.com/books?id=NW0jvr2enWQC&pg=PA432 |year=2005 |publisher=[[University of Chicago Press]] |isbn=978-0-226-08090-1 |page=432}}</ref> without actually studying survival value in the field.<ref name="Burkhardt2005"/> The [[evolutionary biologist]] [[Richard Dawkins]] wrote that Lorenz was a {{"'}}good of the species' man",<ref name=Dawkins1976>{{harvnb|Dawkins|1976|pp=9, 72}}</ref> so accustomed to group selection thinking that he did not realize his views "contravened [[Neo-Darwinism|orthodox Darwinian theory]]".<ref name=Dawkins1976/> The [[Ethology|ethologist]] [[Niko Tinbergen]] praised Lorenz for his interest in the survival value of behaviour, and naturalists enjoyed Lorenz's writings for the same reason.<ref name="Burkhardt2005"/> In 1962, group selection was used as a popular explanation for adaptation by the zoologist [[V. C. Wynne-Edwards]].<ref>{{cite book |last=Wynne-Edwards |first=V. C. |author-link=V. C. Wynne-Edwards |year=1962 |title=Animal Dispersion in Relation to Social Behaviour |location=Edinburgh |publisher=[[Oliver and Boyd]] |oclc=776867845}}</ref><ref>Wynne-Edwards, V. C. (1986) ''Evolution Through Group Selection'', [[Wiley-Blackwell|Blackwell]]. {{ISBN|0-632-01541-1}}</ref> In 1976, Dawkins wrote a well-known book on the importance of evolution at the level of the [[gene]] or the individual, ''[[The Selfish Gene]]''.<ref name="Selfish-Gene">{{harvnb|Dawkins|1976}}</ref>

From the mid-1960s, [[evolutionary biologists]] argued that [[natural selection]] acted primarily at the level of the individual. In 1964, [[John Maynard Smith]],<ref>{{Cite journal |doi=10.1038/2011145a0 |last1=Maynard Smith |first1=J. |author-link=John Maynard Smith |year=1964 |title=Group selection and kin selection |journal=[[Nature (journal)|Nature]] |volume=201 |issue=4924 |pages=1145–1147 |bibcode=1964Natur.201.1145S|s2cid=4177102 }}</ref> [[C. M. Perrins]] (1964),<ref name="Williams">{{cite book |last=Perrins |first=Chris |author-link=C. M. Perrins |editor=Williams, George C. |editor-link=George C. Williams (biologist) |title=Survival of Young Swifts in Relation to Brood-Size |work=Group Selection |url=https://books.google.com/books?id=UWwbPIPkQZYC&pg=PA116 |publisher=[[Transaction Publishers]] |isbn=978-0-202-36635-7 |pages=116–118 |year=2017 }}</ref> and [[George C. Williams (biologist)|George C. Williams]] in his 1966 book ''[[Adaptation and Natural Selection]]'' cast serious doubt on group selection as a major mechanism of evolution; Williams's 1971 book ''[[Group Selection (book)|Group Selection]]'' assembled writings from many authors on the same theme.<ref>{{cite book |author-link=George C. Williams (biologist) |last=Williams |first=George C. |year=1972 |title=Adaptation and Natural Selection: A Critique of Some Current Evolutionary Thought |publisher=[[Princeton University Press]] |isbn=978-0-691-02357-1|title-link=Adaptation and Natural Selection: A Critique of Some Current Evolutionary Thought }}</ref><ref>{{cite book |editor=Williams, George C. |year=2008 |orig-year=1971 |title-link=Group Selection (book) |title=Group Selection |publisher=[[Transaction Publishers]] |isbn=978-0-202-36222-9}}</ref>

It was in the 1960s generally agreed that group selection also applied for [[Eusociality|eusocial]] insects such as [[honeybee]]s.<ref name="response to Nowak">{{Cite journal |last1=Strassmann |first1=Joan E. |author-link=Joan E. Strassmann |last2=Page |first2=Robert E. |author-link2=Robert E. Page Jr. |last3=Robinson |first3=Gene E. |author-link3=Gene E. Robinson |last4=Seeley |first4=Thomas D. |author-link4=Thomas Dyer Seeley |date=March 2011 |title=Kin selection and eusociality |url=https://www.nature.com/articles/nature09833 |journal=[[Nature (journal)|Nature]] |volume=471 |issue=7339 |pages=E5–E6 |doi=10.1038/nature09833 |pmid=21430723 |bibcode=2011Natur.471E...5S |s2cid=205224117 |quote=The same points can be made with regard to the evolution of the eusocial insects, which Nowak et al. suggest cannot be explained by inclusive fitness theory. It was already known that haplodiploidy itself may have only a relatively minor bearing on the origin of eusociality, and so Nowak et al. have added nothing new here. Inclusive fitness theory has explained why eusociality has evolved only in monogamous lineages, and why it is correlated with certain ecological conditions, such as extended parental care and defence of a shared resource. Furthermore, inclusive fitness theory has made very successful predictions about behaviour in eusocial insects, explaining a wide range of phenomena. |url-access=subscription }}</ref>

==Kin selection and inclusive fitness theory==

=== Theory makes group selection difficult ===

[[File:Group selection and cheating.svg|thumb|upright=2.5|[[Altruism|Altruistic]] group selection may seem to work well, but individual selection with [[Cheating (biology)|cheating]] works better and replaces it.]]

Experiments from the late 1970s suggested that selection involving groups was possible.<ref>{{Cite journal |doi=10.2307/2407552 |pmid=28567731 |last=Wade |first=M. J. |year=1977 |title=An experimental study of group selection |journal=Evolution |volume=31 |issue=1 |pages=134–153 |jstor=2407552}}</ref> Early group selection models assumed that genes acted independently, for example a gene that coded for cooperation or altruism. Genetically based reproduction of individuals implies that, in group formation, the altruistic genes would need a way to act for the benefit of members in the group to enhance the fitness of many individuals with the same gene.<ref name="Goodnight Stevens 1997">{{cite journal |last1=Goodnight |first1=C. J. |last2=Stevens |first2=L. |year=1997 |title=Experimental studies of group selection: What do they tell us about group selection in nature |journal=American Naturalist |volume=150 |issue=S1 |pages=S59–S79 |doi=10.1086/286050|pmid=18811313 |bibcode=1997ANat..150S..59G |s2cid=20931060 }}</ref> But it is expected from this model that individuals of the same species would compete against each other for the same resources. This would put cooperating individuals at a disadvantage, making genes for cooperation likely to be eliminated.<ref name="Selfish-Gene"/><ref name="Strassmann2000">{{cite journal |last1=Strassmann |first1=J. E. |author2=Zhu, Y. |author3=Queller, D.C. |title=Altruism and social cheating in the social amoeba Dictyostelium discoideum |journal=Nature |date=2000 |volume=408 |issue=6815 |pages=965–967 |doi=10.1038/35050087 |pmid=11140681 |bibcode=2000Natur.408..965S |s2cid=4307980}}</ref> Group selection on the level of the species is flawed because it is difficult to see how selective pressures would be applied to competing/non-cooperating individuals.<ref name="Selfish-Gene"/>

=== Alternative explanation of altruism ===

{{Further|Kin selection|Inclusive fitness}}

Unlike group selection, [[kin selection]] between related individuals is accepted by most biologists as an explanation of altruistic behaviour.<ref name="response to Nowak"/> [[R.A. Fisher]] in 1930<ref>{{cite book |title=The Genetical Theory of Natural Selection |last=Fisher |first=R. A. |author-link=R.A. Fisher |year=1930 |publisher=[[Clarendon Press]] |location=Oxford |page=[https://archive.org/details/in.ernet.dli.2015.221869/page/n186 159] |url=https://archive.org/details/in.ernet.dli.2015.221869}}</ref> and [[J.B.S. Haldane]] in 1932<ref>{{cite book |title=The Causes of Evolution |last=Haldane |first=J.B.S. |author-link=J. B. S. Haldane |year=1932 |publisher=Longmans, Green & Co. |location=London |url=https://archive.org/details/causesofevolutio00hald_0}}</ref> set out the mathematics of kin selection, with Haldane famously joking that he would willingly die for two brothers or eight cousins.<ref name="quote">{{cite book |year=1999 |title=Psychologically Speaking: A Book of Quotations |chapter=Altruism |editor1=Kevin Connolly |editor2=Margaret Martlew |pages=10 |publisher=BPS Books |isbn=978-1-85433-302-5}} (see also: [[:wikiquote:J. B. S. Haldane|Haldane's Wikiquote entry]])</ref> In this model, genetically related individuals cooperate because survival advantages to one individual also benefit kin who share some fraction of the same genes, giving a mechanism for selection in favour of this much altruism, without involving group selection.<ref name=WadeEtAl2010>{{cite journal |last1=Wade |first1=M. J. |last2=Wilson |first2=David Sloan |author2-link=David Sloan Wilson |author3=Goodnight, Charles |author4=Taylor, D. |author5=Bar-Yam, Y. |author6=de Aguiar, M. A. |author7=Stacey, B. |author8=Werfel, J. |author9=Hoelzer, G. A. |author10=Brodie, E. D. |author11=Fields, P. |author12=Breden, F. |author13=Linksvayer, T. A. |author14=Fletcher, J. A. |author15=Richerson, P. J. |author16=Bever, J. D. |author17=Van Dyken, J. D. |author18=Zee, P. |display-authors=5 |title=Multilevel and kin selection in a connected world |journal=[[Nature (journal)|Nature]] |date=Feb 18, 2010 |volume=463 |issue=7283 |pages=E8–9; discussion E9–10 |pmid=20164866 |doi=10.1038/nature08809 |pmc=3151728 |bibcode=2010Natur.463....8W }}</ref>

[[Inclusive fitness]] theory, first proposed by [[W. D. Hamilton]] in the early 1960s, gives a selection criterion for evolution of social traits when social behaviour is costly to an individual organism's survival and reproduction. The criterion is that the reproductive benefit to relatives who carry the social trait, multiplied by their relatedness (the probability that they share the altruistic trait) exceeds the cost to the individual. Inclusive fitness theory is a general treatment of the statistical probabilities of social traits accruing to any other organisms likely to propagate a copy of the same social trait. Kin selection theory treats the narrower but simpler case of the benefits to close genetic relatives (or what biologists call 'kin') who may also carry and propagate the trait. The theory is widely accepted<!--the response to Nowak is described in the next section--> by biologists.<ref name="response to Nowak"/>

=== Kin recognition ===

{{further|Kin recognition}}

One of the questions about kin selection is the requirement that individuals must know if other individuals are related to them, or [[kin recognition]]. Any altruistic act has to preserve similar genes. One argument given by Hamilton is that many individuals operate in "viscous" conditions, so that they live in physical proximity to relatives. Under these conditions, they can act altruistically to any other individual, and it is likely that the other individual will be related. This population structure builds a continuum between individual selection, kin selection, kin group selection and group selection without clear boundaries between these. However, early theoretical models by D. S. Wilson et al.<ref>{{cite journal |last1=Wilson |first1=David Sloan |author-link=David Sloan Wilson |last2=Pollock |first2=G. B. |last3=Dugatkin |first3=L. A. |title=Can altruism evolve in purely viscous populations? |journal=Evolutionary Ecology |year=1992 |volume=6 |issue=4 |pages=331–341 |doi=10.1007/bf02270969|bibcode=1992EvEco...6..331W |s2cid=26014121 }}</ref> and P. D. Taylor<ref>{{cite journal |last=Taylor |first=P. D. |title=Altruism in viscous populations – an inclusive fitness model |journal=Evolutionary Ecology |year=1992 |volume=6 |issue=4 |pages=352–356 |doi=10.1007/bf02270971|bibcode=1992EvEco...6..352T |s2cid=24652191 }}</ref> showed that pure population viscosity cannot lead to cooperation and altruism. This is because any benefit generated by kin cooperation is exactly cancelled out by kin competition; additional offspring from cooperation are eliminated by local competition. Mitteldorf and D. S. Wilson later showed that if the population is allowed to fluctuate, local populations can temporarily store the benefit of local cooperation and promote the evolution of cooperation and altruism.<ref>{{cite journal |last1=Mitteldorf |first1=Joshua |last2=Wilson |first2=David Sloan |author2-link=David Sloan Wilson |title=Population viscosity and the evolution of altruism |journal=Journal of Theoretical Biology |year=2000 |volume=204 |issue=4 |pages=481–496 |url=http://web.pdx.edu/~jeff/group_sel_workshop/mitteldorf_wilson.pdf |doi=10.1006/jtbi.2000.2007 |pmid=10833350 |bibcode=2000JThBi.204..481M |citeseerx=10.1.1.144.8232 }}</ref> By assuming individual differences in adaptations, Jiang-Nan Yang further showed that the benefit of local altruism can be stored in the form of offspring quality and thus promote the evolution of altruism even if the population does not fluctuate. This is because local competition among more individuals resulting from local altruism increases the average local fitness of the individuals that survive.<ref name="Yang 2013">{{cite journal |last=Yang |first=Jiang-Nan |title=Viscous populations evolve altruistic programmed aging in ability conflict in a changing environment |journal=Evolutionary Ecology Research |year=2013 |volume=15 |pages=527–543 |url=https://www.researchgate.net/publication/255170953}}</ref>

=== Reciprocal altruism ===

{{further|Reciprocal altruism}}

Another explanation for the recognition of genes for altruism is that a single trait, [[reciprocal altruism]], is capable of explaining the vast majority of altruism that is generally accepted as "good" by modern societies. The phenotype of altruism relies on recognition of the altruistic behaviour by itself. The trait of kindness is recognized by sufficiently intelligent and undeceived organisms in other individuals with the same trait. Moreover, the existence of such a trait predicts a tendency for kindness to unrelated organisms that are apparently kind, even if the organisms are of another species. The gene need not be exactly the same, so long as the effect or phenotype is similar. Multiple versions of the gene—or even [[meme]]—would have virtually the same effect. This explanation was given by Richard Dawkins as an analogy of a man with a [[Green beard effect|green beard]]. Green-bearded men are imagined as tending to cooperate with each other simply by seeing a green beard, where the green beard trait is incidentally linked to the reciprocal kindness trait.<ref name="Selfish-Gene"/>

== Multilevel selection theory ==

=== Context ===

{{Further|Unit of selection}}

Early group selection models were flawed because they assumed that genes acted independently; but genetically based interactions among individuals are ubiquitous in group formation because genes must cooperate for the benefit of association in groups to enhance the fitness of group members.<ref name="Goodnight Stevens 1997"/> Additionally, group selection at the species level is flawed because it is difficult to see how selective pressures would be applied; selection in social species of groups against other groups, rather than the species entire, would be more plausible. In contrast, kin selection is accepted as an explanation of altruistic behaviour.<ref name=WadeEtAl2010/><ref>{{cite web |url=http://scienceblogs.com/evolution/2010/09/04/open-letter-to-richard-dawkins/ |title=open letter to Richard Dawkins |last=Wilson |first=David Sloan |author-link=David Sloan Wilson |date=2010 |website=scienceblogs.com |publisher=Self-published |access-date=12 January 2015 |archive-url=https://web.archive.org/web/20160316234245/http://scienceblogs.com/evolution/2010/09/04/open-letter-to-richard-dawkins/ |archive-date=16 March 2016 |url-status=dead }}</ref> The biologist Charles Goodnight argues that kin selection and multilevel selection are both needed to "obtain a complete understanding of the evolution of a social behavior system".<ref name="Goodnight 2013">{{cite journal |last=Goodnight |first=Charles |date=June 2013 |title=On multilevel selection and kin selection: Contextual analysis meets direct fitness |journal=[[Evolution (journal)|Evolution]] |volume=67 |issue=6 |pages=1539–1548 |doi=10.1111/j.1558-5646.2012.01821.x |pmid=23730749 |doi-access=free }}</ref>

=== A revived group selection theory ===

In 1994, the evolutionary biologist [[David Sloan Wilson]] and the philosopher of biology [[Elliott Sober]] argued that the case against group selection had been overstated. They considered whether groups can have functional organization in the same way as individuals, and consequently whether groups can be "vehicles" for [[Selection (biology)|selection]]. They do not posit evolution on the level of the species, but selective pressures that winnow out small groups within a species, e.g. groups of social insects or primates. Groups that cooperate better might survive and reproduce more than those that did not. Resurrected in this way, D. S. Wilson & Sober's new group selection is called multilevel selection theory.<ref>{{cite journal |last1=Wilson |first1=David Sloan |author1-link=David Sloan Wilson |last2=Sober |first2=Elliott |author2-link=Elliott Sober |year=1994 |title=Reintroducing group selection to the human behavioral sciences |journal=Behavioral and Brain Sciences |volume=17 |issue=4 |pages=585–654 |doi=10.1017/s0140525x00036104 }}</ref>

[[File:Wilson's Matryoshka Doll Multilevel Selection Model.jpg|thumb|upright=1.3|[[David Sloan Wilson]] and [[Elliott Sober]]'s 1994 Multilevel [[Selection (biology)|Selection]] Model, illustrated by a nested set of Russian [[matryoshka doll]]s. Wilson himself compared his model to such a set.|alt=David Sloan Wilson compared multilevel selection to a nested set of Russian dolls]]

D. S. Wilson compared the layers of competition and evolution to nested sets of Russian [[matryoshka doll]]s.<ref name="Wilson, D. S. 2008">{{cite journal |last1=Wilson |first1=David Sloan |author1-link=David Sloan Wilson |last2=Wilson |first2=E. O. |author2-link=E. O. Wilson |year=2008 |title=Evolution 'for the good of the group' |journal=American Scientist |volume=96 |issue=5 |pages=380–389 |doi=10.1511/2008.74.1}}</ref> The lowest level is the [[gene]]s, next come the [[cell (biology)|cells]], then the [[organism]] level and finally the groups. The different levels function cohesively to maximize fitness, or reproductive success. The theory asserts that selection for the group level, involving competition between groups, must outweigh the individual level, involving individuals competing within a group, for a group-benefiting trait to spread.<ref name="O'Gorman, R. 2008">{{cite journal |last1=O'Gorman |first1=R. |last2=Wilson |first2=David Sloan |author2-link=David Sloan Wilson  |last3=Sheldon |first3=K. M. |year=2008 |title=For the good of the group? Exploring group-level evolutionary adaptations using multilevel selection theory |journal=[[Group Dynamics: Theory, Research, and Practice]] |volume=12 |issue=1 |pages=17–26 |doi=10.1037/1089-2699.12.1.17 |url=http://repository.essex.ac.uk/1635/1/MLS%20and%20social%20psychology.pdf }}</ref>

Multilevel selection theory focuses on the phenotype because it looks at the levels that selection directly acts upon.<ref name="Wilson, D. S. 2008"/> For humans, social norms can be argued to reduce individual level variation and competition, thus shifting selection to the group level. The assumption is that variation between different groups is larger than variation within groups. Competition and selection can operate at all levels regardless of scale. D. S. Wilson wrote, "At all scales, there must be mechanisms that coordinate the right kinds of action and prevent disruptive forms of self-serving behavior at lower levels of social organization."<ref name="DSWilson1"/> E. O. Wilson summarized, "In a group, selfish individuals beat altruistic individuals. But, groups of altruistic individuals beat groups of selfish individuals."<ref name="DSWilson-Edge">{{cite web |last1=Wilson |first1=David Sloan |author1-link=David Sloan Wilson |title=The Central Question of Group Selection |url=https://www.edge.org/conversation/the-false-allure-of-group-selection#dsw |publisher=Edge.org |access-date=19 Apr 2018}}</ref>

D. S. Wilson argues that while kin selection works well for the behaviour of many animals, human behaviour is difficult to explain using kin selection alone. In particular, he claims it does not explain the rapid rise of human civilization, and that other factors must be considered.<ref name="DSWilson1">{{cite book |last=Wilson |first=David Sloan |author-link=David Sloan Wilson |title=Does Altruism Exist?: Culture, Genes, and the Welfare of Others |date=2015 |publisher=[[Yale University Press]] |isbn=978-0-300-18949-0}}</ref> He and others have continued to develop group selection models.<ref name="Yang 2013"/><ref>{{cite journal |last=Koeslag |first=J. H. |date=1997 |title=Sex, the prisoner's dilemma game, and the evolutionary inevitability of cooperation |journal=Journal of Theoretical Biology |volume=189 |issue=1 |pages=53–61 |doi=10.1006/jtbi.1997.0496 |pmid=9398503 |bibcode=1997JThBi.189...53K }}
<br/>{{cite journal |last=Koeslag |first=J. H.  |date=2003 |title=Evolution of cooperation: cooperation defeats defection in the cornfield model |journal=Journal of Theoretical Biology |volume=224 |issue=3 |pages=399–410 |doi=10.1016/s0022-5193(03)00188-7 |pmid=12941597 |bibcode=2003JThBi.224..399K }}
<br/>{{cite web |last1=Wilson |first1=David Sloan |author-link=David Sloan Wilson |title=open letter to Richard Dawkins |date=2010 |url=http://scienceblogs.com/evolution/2010/09/04/open-letter-to-richard-dawkins/ |website=scienceblogs.com |publisher=[[David Sloan Wilson]] |access-date=12 January 2015 |archive-url=https://web.archive.org/web/20160316234245/http://scienceblogs.com/evolution/2010/09/04/open-letter-to-richard-dawkins/ |archive-date=16 March 2016 |url-status=dead }}</ref><ref name="Goodnight 2013"/> He ties the multilevel selection theory regarding humans to another theory, [[gene–culture coevolution]], by acknowledging that culture seems to characterize a group-level mechanism for human groups to adapt to environmental changes.<ref name="O'Gorman, R. 2008"/>

D. S. Wilson and Sober's work revived interest in multilevel selection. In a 2005 article, E. O. Wilson argued that kin selection could no longer be thought of as underlying the evolution of extreme sociality, for two reasons. First, he suggested, the argument that [[haplodiploid]] inheritance (as in the Hymenoptera) creates a strong selection pressure towards nonreproductive castes is mathematically flawed.<ref>{{cite journal |last=Wilson |first=E. O. |author-link=E. O. Wilson |year=2005 |title=Kin Selection as the Key to Altruism: its Rise and Fall |journal=[[Social Research (journal)|Social Research]] |volume=72 |issue=1 |pages=159–166 |doi=10.1353/sor.2005.0012 |s2cid=142713581 }}</ref><ref>{{cite journal |last1=Trivers |first1=Robert |author-link=Robert Trivers |year=1976 |title=Haploidploidy and the evolution of the social insect |journal=[[Science (journal)|Science]] |volume=191 |issue=4224 |pages=250–263 |doi=10.1126/science.1108197 |pmid=1108197 |bibcode=1976Sci...191..249T }}</ref> Second, [[eusociality]] no longer seems to be confined to the hymenopterans; increasing numbers of highly social taxa have been found in the years since E. O. Wilson's foundational text ''[[Sociobiology: A New Synthesis]]'' was published in 1975.<ref name="Wilson75">{{cite book |last=Wilson |first=E. O. |author-link=E. O. Wilson |year=1975 |title=Sociobiology: The New Synthesis |publisher=[[Belknap Press]] |isbn=978-0-674-81621-3 |url-access=registration |url=https://archive.org/details/sociobiologynews00wilsrich }}</ref> These including a variety of insect species, as well as two rodent species (the [[naked mole-rat]] and the [[Damaraland mole rat]]). E. O. Wilson suggests that the equation for [[Hamilton's rule]]:<ref>{{Cite journal |last1=Hamilton |first1=W. D. |author-link=W. D. Hamilton |year=1964 |title=The evolution of social behaviour |title-link=The Evolution of Social Behaviour |journal=[[Journal of Theoretical Biology]] |volume=7 |issue=1 |pages=1–16 |doi=10.1016/0022-5193(64)90038-4 |pmid=5875341|bibcode=1964JThBi...7....1H |s2cid=5310280 }}</ref>

:::rb > c

(where b represents the benefit to the recipient of altruism, c the cost to the altruist, and r their degree of relatedness) should be replaced by the more general equation

:::rb<sub>k</sub> + b<sub>e</sub> > c

in which b<sub>k</sub> is the benefit to kin (b in the original equation) and b<sub>e</sub> is the benefit accruing to the group as a whole. He then argues that, in the present state of the evidence in relation to social insects, it appears that b<sub>e</sub>>rb<sub>k</sub>, so that altruism needs to be explained in terms of selection at the colony level rather than at the kin level. However, kin selection and group selection are not distinct processes, and the effects of multi-level selection are already accounted for in Hamilton's rule, ''rb''>''c'',<ref name="West Griffin Gardner 2007">{{cite journal |last1=West |first1=S. A. |last2=Griffin |first2=A. S. |last3=Gardner |first3=A. |date=2007 |url=https://science.umd.edu/faculty/wilkinson/BIOL608W/WestGriffinGardner_08.pdf |title=Social semantics: altruism, cooperation, mutualism, strong reciprocity and group selection |journal=[[Journal of Evolutionary Biology]] |volume=20 |issue=2 |pages=415–432 |doi=10.1111/j.1420-9101.2006.01258.x |pmid=17305808 |doi-access=free |url-access=subscription }}</ref> provided that an expanded definition of ''r'', not requiring Hamilton's original assumption of direct genealogical relatedness, is used, as proposed by E. O. Wilson himself.<ref>{{cite journal |title=Rethinking the Theoretical Foundation of Sociobiology |url=http://mechanism.ucsd.edu/teaching/philbio/readings/wilson-wilson.rethinking%20sociobiology.inpress.pdf |last=Wilson |first=David Sloan |author-link=David Sloan Wilson |journal=[[The Quarterly Review of Biology]] |year=2007 |volume=82 |issue=4 |pages=327–48 |doi=10.1086/522809 |pmid=18217526 |s2cid=37774648 |access-date=10 September 2013 |archive-url=https://web.archive.org/web/20131208085754/http://mechanism.ucsd.edu/teaching/philbio/readings/wilson-wilson.rethinking%20sociobiology.inpress.pdf |archive-date=8 December 2013 |url-status=dead }}</ref>

=== Debate in ''Nature'' ===

In 2010, the mathematical biologists [[Martin Nowak]] and [[Corina Tarnita]], with the entomologist [[E. O. Wilson]], argued in ''[[Nature (journal)|Nature]]'' for multi-level selection, including group selection, to correct what they saw as deficits in the explanatory power of inclusive fitness.<ref name="Nowak Tarnita Wilson 2010"/> 137 other evolutionary biologists, also in ''Nature'', responded "that their arguments are based upon a misunderstanding of evolutionary theory and a misrepresentation of the empirical literature".<ref name="137 authors reply to Nowak 2011">{{cite journal |last1=Abbot |first1=Patrick |last2=Abe |first2=Jun |last3=Alcock |first3=John |last4=Alizon |first4=Samuel |last5=Alpedrinha |first5=Joao A. 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=== Proposed applications ===

[[File:Apis mellifera (queen and workers).jpg|thumb|upright|[[Social behaviour]] in [[honeybee]]s looked a good candidate for group selection, but is explained by [[kin selection]]: their [[haplodiploid]] inheritance system makes [[worker (bee)|workers]] very closely related to their [[queen (insect)|queen]] (centre).<ref name="response to Nowak"/>]]

Multi-level selection theory is proposed as suitable for evaluating the balance between group selection and individual selection in specific cases.<ref name="O'Gorman, R. 2008"/> An experiment by William Muir compared egg productivity in hens, showing that a hyper-aggressive strain had been produced through individual selection, leading to many fatal attacks after only six generations; by implication, it could be argued that group selection must have been acting to prevent this in real life.<ref>{{cite journal |last=Muir |first=W. M. |year=2009 |title=Genetic selection and behaviour |journal=[[Canadian Journal of Animal Science]] |volume=89 |issue=1 |pages=182}}</ref> Group selection has most often been postulated in humans<ref>{{cite journal |last1=Boyd |first1=R. |last2=Richerson |first2=P. J. |year=2009 |title=Culture and the evolution of human cooperation |journal=[[Philosophical Transactions of the Royal Society B]] |volume=364 |issue=1533 |pages=3281–3288 |doi=10.1098/rstb.2009.0134 |pmid=19805434 |pmc=2781880 }}</ref> and in [[eusocial]] [[Hymenoptera]] such as honeybees that make cooperation a driving force of their adaptations over time, and therefore seemed likely candidates for group selection. However, eusocial insects have a unique system of inheritance involving [[haplodiploidy]] that allows the colony to function as an individual while only the queen reproduces.<ref name="response to Nowak"/>

=== Evidence on both sides ===

Spatial populations of predators and prey show restraint of reproduction at equilibrium, both individually and through social communication, as originally proposed by Wynne-Edwards. While these spatial populations do not have well-defined groups for group selection, the local spatial interactions of organisms in transient groups are sufficient to lead to a kind of multi-level selection. There is however as yet no evidence that these processes operate in the situations where Wynne-Edwards posited them.<ref name="Rauch">{{cite journal |last1=Rauch |first1=E. M. |last2=Sayama |first2=H. |last3=Bar-Yam |first3=Y. |year=2003 |title=Dynamics and genealogy of strains in spatially extended host-pathogen models |journal=[[Journal of Theoretical Biology]] |volume=221 |issue=4 |pages=655–664 |doi=10.1006/jtbi.2003.3127 |pmid=12713947 |bibcode=2003JThBi.221..655R |citeseerx=10.1.1.12.5712 }}</ref><ref>{{cite journal |last1=Werfel |first1=J. |last2=Bar-Yam |first2=Y. |year=2004 |title=The evolution of reproductive restraint through social communication |journal=[[PNAS]] |volume=101 |issue=30 |pages=11019–11020 |doi=10.1073/pnas.0305059101 |pmid=15256603 |pmc=491990 |bibcode=2004PNAS..10111019W |doi-access=free }}</ref> Rauch et al.'s analysis of host-[[parasite]] evolution, on the other hand, is broadly hostile to group selection. Specifically, the parasites do not individually moderate their transmission; rather, more transmissible variants – which have a short-term but unsustainable advantage – arise, increase, and go extinct.<ref name=Rauch/>

==Applications==

=== Differing evolutionarily stable strategies ===
{{Further|Evolutionarily stable strategy}}

The problem with group selection is that for a whole group to get a single trait, it must spread through the whole group first by regular evolution. But, as [[J. L. Mackie]] suggested, when there are many different groups, each with a different [[evolutionarily stable strategy]], there is selection between the different strategies, since some are worse than others.{{sfn|Dawkins|1976|pp=74–94}} For example, a group where altruism was universal would indeed outcompete a group where every creature acted in its own interest, so group selection might seem feasible; but a mixed group of altruists and non-altruists would be vulnerable to [[Cheating (biology)|cheating]] by non-altruists within the group, so group selection would collapse.<ref>{{cite book |last=Axelrod |first=Robert |date=1984 |title=The Evolution of Cooperation |url=https://archive.org/details/evolutionofcoope1984axel |url-access=registration |publisher=Basic Books |page=[https://archive.org/details/evolutionofcoope1984axel/page/98 98] |isbn=978-0465005642 }}</ref>

===Implications in population biology===

[[Altruism in animals|Altruism]] and group relationships can impact many aspects of population dynamics, such as [[intraspecific competition]] and [[Interspecific competition|interspecific]] interactions. In 1871, Darwin argued that group selection occurs when the benefits of cooperation or altruism between subpopulations are greater than the individual benefits of egotism within a subpopulation.<ref name="DOM"/> This supports the idea of multilevel selection, but kinship also plays an integral role because many subpopulations are composed of closely related individuals. An example of this can be found in lions, which are simultaneously cooperative and territorial.<ref name=Heinsohn>{{cite journal |last1=Heinsohn |first1=R. |last2=Packer |first2=C. |year=1995 |title=Complex cooperative strategies in group-territorialAfrican lions |journal=Science |volume=269 |issue=5228 |pages=1260–1262 |doi=10.1126/science.7652573 |pmid=7652573 |bibcode=1995Sci...269.1260H |s2cid=35849910 }}</ref> Within a pride, males protect the pride from outside males, and females, who are commonly sisters, communally raise cubs and hunt. However, this cooperation seems to be density dependent. When resources are limited, group selection favours prides that work together to hunt. When prey is abundant, cooperation is no longer beneficial enough to outweigh the disadvantages of altruism, and hunting is no longer cooperative.<ref name=Heinsohn/>

Interactions between different species, including predator-prey relationships, can be affected by multilevel selection. Individuals of certain monkey species howl to warn the group of the approach of a predator.<ref name=Cheney>{{cite book |last1=Cheney |first1=D. L. |last2=Seyfarth |first2=R. M. |date=1990 |title=How monkeys see the world: Inside the mind of another species |url=https://archive.org/details/howmonkeysseewor00chenrich |url-access=registration |publisher=[[University of Chicago Press]] |isbn=978-0-226-10246-7 }}</ref> The evolution of this trait benefits the group by providing protection, but could be disadvantageous to the individual if the howling draws the predator's attention to them. By affecting these interspecific interactions, multilevel and kinship selection can change the population dynamics of an ecosystem.<ref name=Cheney/>

Multilevel selection attempts to explain the evolution of altruism in terms of [[quantitative genetics]]. Increased frequency or [[Fixation (population genetics)|fixation]] of altruistic [[allele]]s can be accomplished through kin selection, in which individuals behave altruistically to promote the fitness of genetically similar individuals such as their siblings. This can lead to [[inbreeding depression]],<ref>{{cite journal |last1=Wade |first1=M. J. |last2=Breden |first2=Sept |year=1981 |title=Effect of Inbreeding on the Evolution of Altruistic Behavior by Kin Selection |journal=Evolution |volume=35 |issue=5|pages=844–858 |doi=10.2307/2407855 |pmid=28581060 |jstor=2407855 }}</ref> which typically lowers the overall fitness of a population. However, if altruism were to be selected for through an emphasis on benefit to the group as opposed to relatedness and benefit to kin, both the altruistic trait and genetic diversity could be preserved. Relatedness should still remain a key consideration in studies of multilevel selection. Experimentally imposed multilevel selection on Japanese quail was some ten times more effective on closely related kin groups than on randomized groups of individuals.<ref>{{cite journal |last1=Muir |first1=W. M. |display-authors=etal |date=June 2013 |title=Multilevel selection with kin and non-kin groups, Experimental results with Japanese quail |journal=[[Evolution (journal)|Evolution]] |volume=67 |issue=6|pages=1598–1606 |doi=10.1111/evo.12062 |pmid=23730755 |pmc=3744746}}</ref>

===Gene-culture coevolution in humans===

{{Main|Dual inheritance theory|cultural group selection}}

[[File:Sri Mariamman Temple Singapore 3 amk.jpg|thumb|upright|Humanity has developed extremely rapidly, arguably through [[gene-culture coevolution]], leading to complex [[culture|cultural]] artefacts like the [[gopuram]] of the Sri Mariammam temple, Singapore.|alt=Gene-culture coevolution allows humans to develop complex artefacts like elaborately decorated temples]]

[[Gene-culture coevolution]] (also called dual inheritance theory) is a modern hypothesis (applicable mostly to humans) that combines evolutionary biology and modern sociobiology to indicate group selection.<ref>{{cite journal |last1=Mesoudi |first1=A. |last2=Danielson |first2=P. |year=2008 |title=Ethics, evolution and culture |journal=Theory in Biosciences |volume=127 |issue=3 |pages=229–240 |doi=10.1007/s12064-008-0027-y |pmid=18357481|s2cid=18643499 }}</ref> It is believed that this approach of combining genetic influence with cultural influence over several generations is not present in the other hypotheses such as reciprocal altruism and kin selection, making gene-culture evolution one of the strongest realistic hypotheses for group selection. Fehr provides evidence of group selection taking place in humans presently with experimentation through logic games such as prisoner's dilemma, the type of thinking that humans have developed many generations ago.<ref>{{cite journal |last1=Fehr |first1=E. |last2=Fischbacher |first2=Urs |year=2003 |title=The nature of human altruism. [Review] |journal=Nature |volume=425 |issue=6960 |pages=785–791 |doi=10.1038/nature02043 |pmid=14574401 |bibcode=2003Natur.425..785F |s2cid=4305295 }}</ref>

Gene-culture coevolution allows humans to develop highly distinct adaptations to the local pressures and environments more quickly than with genetic evolution alone. [[Robert Boyd (anthropologist)|Robert Boyd]] and [[Peter J. Richerson]], two strong proponents of cultural evolution, postulate that the act of social learning, or learning in a group as done in group selection, allows human populations to accrue information over many generations.<ref name="Boyd, R. 2009">{{cite journal |last1=Boyd |first1=R. |last2=Richerson |first2=P. J. |year=2009 |title=Culture and the evolution of human cooperation |journal=Philosophical Transactions of the Royal Society B: Biological Sciences |volume=364 |issue=1533 |pages=3281–3288 |doi=10.1098/rstb.2009.0134|pmid=19805434 |pmc=2781880 }}</ref> This leads to cultural evolution of behaviours and technology alongside genetic evolution. Boyd and Richerson believe that the ability to collaborate evolved during the Middle [[Pleistocene]], a million years ago, in response to a rapidly changing climate.<ref name="Boyd, R. 2009"/>

In 2003, the ethologist [[Herbert Gintis]] examined cultural evolution statistically, offering evidence that societies that promote pro-social norms have higher survival rates than societies that do not.<ref>{{Cite journal |last1=Gintis |first1=H. |year=2003 |title=The hitchhiker's guide to altruism: Gene-culture coevolution, and the internalization of norms |journal=Journal of Theoretical Biology |pmid=12623279 |volume=220 |issue=4 |pages=407–418 |doi=10.1006/jtbi.2003.3104 |bibcode=2003JThBi.220..407G |s2cid=6190689 }}</ref> Gintis wrote that genetic and cultural evolution can work together. Genes transfer information in DNA, and cultures transfer information encoded in brains, artifacts, or documents. Language, tools, lethal weapons, fire, cooking, etc., have a long-term effect on genetics. For example, cooking led to a reduction of size of the human gut, since less digestion is needed for cooked food. Language led to a change in the human larynx and an increase in brain size. Projectile weapons led to changes in human hands and shoulders, such that humans are much better at throwing objects than the closest human relative, the chimpanzee.<ref name="Gintis-Edge">{{cite web |last=Gintis |first=Herbert |title=On the Evolution of Human Morality |url=https://www.edge.org/conversation/the-false-allure-of-group-selection#hg |publisher=[[Edge.org]] |access-date=20 Apr 2018}}</ref>

In 2015, William Yaworsky and colleagues surveyed the opinions of anthropologists on group selection, finding that these varied with the gender and politics of the social scientists concerned.<ref name="Yaworsky 2014">{{cite journal |last1=Yaworsky |first1=William |last2=Horowitz |first2=Mark |last3=Kickham |first3=Kenneth |title=Gender and Politics Among Anthropologists in the Units of Selection Debate |journal=Biological Theory |volume=10 |issue=2 |date=9 December 2014 |issn=1555-5542 |doi=10.1007/s13752-014-0196-5 |pages=145–155 |s2cid=85150030 }}</ref>
In 2019, [[Howard Rachlin]] and colleagues proposed group selection of behavioural patterns, such as learned altruism, during ontogeny parallel to group selection during phylogeny.<ref>{{Cite journal |last=Rachlin |first=Howard |date=April 2019 |title=Group selection in behavioral evolution |journal=Behavioural Processes |volume=161 |pages=65–72 |doi=10.1016/j.beproc.2017.09.005 |pmid=28899811 |s2cid=37938046 |issn=0376-6357}}</ref><ref>{{Cite journal |last1=Simon |first1=Carsta |last2=Hessen |first2=Dag O. |date=April 2019 |title=Selection as a domain-general evolutionary process |journal=Behavioural Processes |volume=161 |pages=3–16 |doi=10.1016/j.beproc.2017.12.020 |pmid=29278778|issn=0376-6357|hdl=10642/8292 |s2cid=24719296 |url=http://urn.nb.no/URN:NBN:no-80696 |hdl-access=free }}</ref><ref>{{Cite journal |last=Baum |first=William M. |date=2018-10-09 |title=Multiscale behavior analysis and molar behaviorism: An overview |journal=Journal of the Experimental Analysis of Behavior |volume=110 |issue=3|pages=302–322 |doi=10.1002/jeab.476 |pmid=30302758 |s2cid=52944940 |issn=0022-5002}}</ref><ref>{{Cite journal |last1=Simon |first1=Carsta |last2=Mobekk |first2=Hilde |date=2019-11-13 |title=Dugnad: A Fact and a Narrative of Norwegian Prosocial Behavior |journal=Perspectives on Behavior Science |volume=42 |issue=4 |pages=815–834 |doi=10.1007/s40614-019-00227-w |pmid=31976461 |pmc=6901638 |issn=2520-8969}}</ref>

== Rejection ==

=== Selfish benefits of 'altruism' ===

{{further|Cheating (biology)|Pursuit deterrence}}

[[File:Stotting gazelle.jpg |thumb |An [[impala]] [[stotting]], [[signalling honestly]] to the predator that the chase will be unprofitable. Such a signal looks costly and [[altruistic]], warning other prey animals that a predator is close, but can benefit the signaller by [[pursuit deterrence|deterring pursuit]].<ref name="Woodland 1980"/>]]
[[File:Group selection and selfish explanations of alarm signals.svg|thumb|right|400px|upright=2.55|An alarm signal looks like costly altruism, making group selection plausible; but it may also [[pursuit deterrence|deter the predator from pursuit]] and create confusion, helping the selfish prey individual to escape.]]

The historian of science [[Peter J. Bowler]] writes that [[George Christopher Williams|G.C. Williams]] and other naturalists "became suspicious"<!-- in the 1960s--> of group selection as an explanation for animal behaviour. A major issue, Bowler writes, is in finding a definitely [[altruistic]] behaviour, because an action like giving an [[alarm signal]] does assist other animals nearby, but it also creates a chaotic event which could, interpreted selfishly, help the caller to escape.<ref name="Bowler 1989">{{cite book |last=Bowler |first=Peter J. |author-link=Peter J. Bowler |title=Evolution |publisher=[[University of California Press]] |publication-place=Berkeley, California |date=1989 |isbn=978-0-520-06386-0 |pages=328–329}}</ref> 

D.J. Woodland and colleagues have proposed, with evidence, that alarm signals have a [[pursuit deterrence]] function, rather than signalling altruistically to other members of their own species.<ref name="Woodland 1980">{{cite journal |last1=Woodland |first1=D. J. |last2=Jaafar |first2=Zarinah |last3=Knight |first3=Mary-Lou |title=The "Pursuit Deterrent" Function of Alarm Signals |journal=[[The American Naturalist]] |volume=115 |issue=5 |date=1980 |doi=10.1086/283596 |pages=748–753 |url=https://www.journals.uchicago.edu/doi/10.1086/283596|url-access=subscription }}</ref> A pursuit deterrence signal can benefit both [[Predation|predator]] and prey: the prey signals that the predator has been detected, possibly saving its own life (as the predator may then decide to give up the pursuit), and saving it and the predator the effort of an unproductive chase.<ref>{{cite journal |last1=Ramesh |first1=Divya |last2=Mitchell |first2=William A. |date=December 2018 |title=Evolution of signalling through pursuit deterrence in a two-prey model using game theory |journal=[[Animal Behaviour (journal)|Animal Behaviour]] |volume=146 |pages=155–163 |doi=10.1016/j.anbehav.2018.10.012 |s2cid=53714343}}</ref>

=== Mathematical issues ===

{{See also|Gene-centered view of evolution}}

Advocates of the [[gene-centered view of evolution]] such as Dawkins and [[Daniel Dennett]] remain unconvinced about group selection.<ref name="River_Out_of_Eden">See the chapter ''[[God's utility function]]'' in {{harvnb|Dawkins|1995}}</ref><ref>{{cite journal |last=Dawkins |first=R. |author-link=Richard Dawkins |year=1994 |title=Burying the Vehicle Commentary on Wilson & Sober: Group Selection |journal=Behavioral and Brain Sciences |volume=17 |issue=4 |pages=616–617 |url=http://www.simonyi.ox.ac.uk/dawkins/WorldOfDawkins-archive/Dawkins/Work/Articles/1994burying_the_vehicle.shtml |archive-url=https://web.archive.org/web/20060915085010/http://www.simonyi.ox.ac.uk/dawkins/WorldOfDawkins-archive/Dawkins/Work/Articles/1994burying_the_vehicle.shtml |archive-date=2006-09-15 |doi=10.1017/S0140525X00036207 |s2cid=143378724 |url-access=subscription }}</ref><ref>{{cite journal |last=Dennett |first=D. C. |author-link=Daniel Dennett |year=1994 |title=E Pluribus Unum? Commentary on Wilson & Sober: Group Selection |url=http://cogprints.org/281/0/wilsonso.htm |journal=Behavioral and Brain Sciences |volume=17 |issue=4 |pages=617–618 |archive-url=https://web.archive.org/web/20071227065311/http://cogprints.org/281/0/wilsonso.htm |archive-date=27 December 2007 |doi=10.1017/S0140525X00036219 |s2cid=146359497 |url-access=subscription }}</ref><ref name=Coyne/> 

The use of the [[Price equation]] to support group selection was challenged by Matthijs van Veelen and colleagues in 2012, arguing that it is based on invalid mathematical assumptions. They created a "simple model"<ref name="dx.doi.org"/> where the Price equation resulted in a wrong prediction, meaning that it only works in some cases.<ref name="dx.doi.org">{{cite journal |last1=van Veelen |first1=Matthijs |last2=García |first2=J. |last3=Sabelis |first3=M. W. |last4=Egas |first4=M. |title=Group selection and inclusive fitness are not equivalent; the Price equation vs. models and statistics |journal=Journal of Theoretical Biology  |volume=299 |pages=64–80 |pmid=21839750 |date=April 2012  |doi=10.1016/j.jtbi.2011.07.025  |bibcode=2012JThBi.299...64V }}</ref> 

The evolutionary biologist [[Jerry Coyne]] summarizes the arguments against group selection in ''[[The New York Review of Books]]'' in non-technical terms as follows:<ref name=Coyne>{{cite news |last=Coyne |first=Jerry A. |author-link=Jerry Coyne |url=https://www.nytimes.com/2011/09/11/books/review/the-neighborhood-project-by-david-sloan-wilson-book-review.html?_r=2&pagewanted=all |title=Can Darwinism Improve Binghamton? |work=[[The New York Review of Books]] |date=9 September 2011}}</ref><!--
Bowler writes that if there was a truly altruistic type of inherited instinctive action, it would die out as "[[Cheating (biology)|cheats]]" would take advantage of the altruists, replacing the inherited altruism with inherited cheating.<ref name="Bowler 1989"/>-->

{{blockquote|Group selection isn't widely accepted by evolutionists for several reasons. First, it's not an efficient way to select for traits, like altruistic behavior, that are supposed to be detrimental to the individual but good for the group. Groups divide to form other groups much less often than organisms reproduce to form other organisms, so group selection for altruism would be unlikely to override the tendency of each group to quickly lose its altruists through natural selection favoring [[Cheating (biology)|cheaters]]. Further, little evidence exists that selection on groups has promoted the evolution of any trait. Finally, other, more plausible evolutionary forces, like direct selection on individuals for reciprocal support, could have made humans prosocial. These reasons explain why only a few biologists, like [David Sloan] Wilson and E. O. Wilson (no relation), advocate group selection as the evolutionary source of cooperation.<ref name=Coyne/>}}

The psychologist [[Steven Pinker]] states that "group selection has no useful role to play in psychology or social science", since in these domains it "is not a precise implementation of the theory of natural selection, as it is, say, in [[genetic algorithm]]s or [[artificial life]] simulations. Instead [in psychology] it is a loose metaphor, more like the struggle among kinds of tires or telephones."<ref name="PinkerFalseAllure">{{cite web |last=Pinker |first=Steven |author-link=Steven Pinker |year=2012 |url=http://edge.org/conversation/the-false-allure-of-group-selection |title=The False Allure of Group Selection |work=Edge |access-date=28 November 2018}}</ref>

=== Replicator–vehicle problem ===

[[File:Vehicles and Replicators.svg|thumb|upright=2.0|In [[Richard Dawkins]]' view of [[evolution]] by [[natural selection]], a vehicle, such as an [[organism]], supports a replicator such as a [[gene]], enabling it to act as a unit of evolution.]]

Dawkins argues that group selection fails to make an appropriate distinction between ''replicators'' (entities able to make [[Copying#Biological copying|copies]] of themselves) and ''vehicles'' (entities that contain replicators).<ref>{{cite book |last=Dawkins |first=Richard |author-link=Richard Dawkins |url=http://www.stephenjaygould.org/library/dawkins_replicators.html |chapter=Replicators and Vehicles |editor=King's College Sociobiology Group |title=Current Problems in Sociobiology |location=Cambridge |publisher=[[Cambridge University Press]] |year=1982 |pages=45–64}}</ref> Entities can only qualify as replicators if their self-copies are made with high-[[fidelity]], they copy themselves [[fecundity|abundantly]], and they survive [[Deep time|long enough to allow evolution to work]].{{sfn|Dawkins|2016|pp=124–146}}{{sfn|Dawkins|2006|pp=21–45}} In support of this, the [[Abiogenesis|origin of life]] seems to have occurred at the same time as [[Self-replication|self-replicating]] molecules appeared, and which eventually formed into [[Unicellular organism|single-celled organisms]].{{sfn|Dawkins|2006|pp=12–20}}{{sfn|Williams|2019|pp=133–138}} While [[Evolutionary pressure|selection pressure]] is exerted through [[phenotype]]s,{{sfn|Dawkins|2016|pp=175–178}} Organisms do not qualify as replicators because [[Lamarckism|acquired characteristics do not get inherited]], while the [[genotype]] of a successful individual gets broken up and rearranged by [[meiosis]] and [[genetic recombination]].{{sfn|Dawkins|2016|pp=147–151}} On the other hand, [[population]]s (groups of organisms) also frequently fragment into separate populations, [[Hybrid (biology)|interbreed]], and are subject to rapid evolutionary change as individuals compete and reproduce.{{sfn|Dawkins|2006|pp=21–45}}{{sfn|Dawkins|2016|pp=151–165}} As such, while genes serve as replicators,{{sfn|Dawkins|2016|pp=124–146}} organisms and populations do not.{{sfn|Dawkins|2016|pp=147–165}}

Randolph Nesse comments that, contrary to Wilson and Sober's view that biologists oppose group selection because they don't grasp the hierarchy of vehicles for selection, they do so because "we lack criteria to determine whether or not a trait arises from group selection". In Nesse's view, there is hardly any evidence for group selection, even though the question of whether it could theoretically serve as a vehicle is not disputed.<ref>{{cite web |last=Nesse |first=Randolph M. |title=Why is group selection such a problem? |journal=Behavioral and Brain Sciences |volume=17 |issue=4 |year=1994 |pages=633-634 |url=https://www.researchgate.net/profile/Randolph-Nesse/publication/240213525_Why_is_group_selection_such_a_problem/links/6441bd0bd577967928f3fa5d/Why-is-group-selection-such-a-problem.pdf}}</ref>

=== Subsumed by inclusive fitness theory ===

S.A. West, A.S. Griffin and A. Gardner write that kin selection theory works at all levels, and that the resulting inclusive fitness approach can be applied, with clearer predictions, wherever group selection can be applied. This treats the effect of group selection as a possible increment to individual selection, both going into the inclusive fitness calculation. Kin selection can, they write, get any result obtained by group selection theory, but more tractably, with testable predictions. Thus, even if a group selection effect exists, it does not negate inclusive fitness, but in their view is unnecessary and adds nothing except "confusing jargon".<ref name="West Griffin Gardner 2007"/>

== References ==

{{reflist|30em}}

== Sources ==

* {{cite book |last=Dawkins |first=Richard |author-link=Richard Dawkins |title=The Selfish Gene |edition=1st |year=1976 |publisher=[[Oxford University Press]] |isbn=978-0198575191|title-link=The Selfish Gene }}
* {{cite book |last=Dawkins |first=Richard |author-link=Richard Dawkins |year=2006 |orig-year=1976 |title=The Selfish Gene |title-link=The Selfish Gene |place=New York |publisher=[[Oxford University Press]] |edition=30th anniversary |isbn=978-0199291151}}
* {{cite book |last=Dawkins |first=Richard |author-link=Richard Dawkins |title=River Out of Eden |title-link=River Out of Eden |publisher=Basic Books |year=1995 |isbn=978-0-465-06990-3 }}
* {{cite book |last=Dawkins |first=Richard |author-link=Richard Dawkins |year=2016 |orig-year=1989 |title=The Extended Phenotype: The Long Reach of the Gene |title-link=The Extended Phenotype |publisher=[[Oxford University Press]] |edition= 2nd |isbn=978-0198788911}}
* {{cite book |last=Williams |first=George C. |author-link=George Christopher Williams |year=2019 |orig-year=1966|title=Adaptation and Natural Selection: A Critique of Some Current Evolutionary Thought |title-link=Adaptation and Natural Selection |publisher=[[Princeton University Press]] |isbn=978-0691182865}}

== Further reading ==

* {{cite journal |last1=Bergstrom |first1=T. C. |year=2002 |title=Evolution of Social Behavior: Individual and Group Selection |url=http://www.econ.ucsb.edu/~tedb/Evolution/groupselection.pdf |journal=[[Journal of Economic Perspectives]] |volume=16 |issue=2 |pages=67–88 |doi=10.1257/0895330027265 |citeseerx=10.1.1.377.5059 |s2cid=125841 |ref=none}}
* {{cite journal |last1=Bijma |first1=P. |last2=Muir |first2=W. M. |last3=Van Arendonk |first3=J. A. M. |year=2007 |title=Multilevel Selection 1: Quantitative Genetics of Inheritance and Response to Selection |journal=[[Genetics (journal)|Genetics]] |pmid=17110494 |volume=175 |issue=1 |pmc=1775021 |pages=277–288 |doi=10.1534/genetics.106.062711 |ref=none}}
* {{cite journal |last1=Bijma |first1=P. |last2=Muir |first2=W. M. |last3=Ellen |first3=E. D. |last4=Wolf |first4=Jason B. |last5=Van Arendonk |first5=J. A. M. |year=2007 |title=Multilevel Selection 2: Estimating the Genetic Parameters Determining Inheritance and Response to Selection |journal=[[Genetics (journal)|Genetics]] |pmid=17110493 |volume=175 |issue=1 |pmc=1775010 |pages=289–299 |doi=10.1534/genetics.106.062729 |ref=none}}
* {{cite journal |last1=Boyd |first1=R. |last2=Richerson |first2=P. J. |year=2002 |title=Group Beneficial Norms Spread Rapidly in a Structured Population |url=http://www.sscnet.ucla.edu/anthro/faculty/boyd/BoydRichersonJTB2002_Clean.pdf |archive-url=https://web.archive.org/web/20050127084337/http://www.sscnet.ucla.edu/anthro/faculty/boyd/BoydRichersonJTB2002_Clean.pdf |url-status=dead |archive-date=January 27, 2005 |journal=[[Journal of Theoretical Biology]] |volume=215 |issue=3 |pages=287–296 |doi=10.1006/jtbi.2001.2515 |pmid=12054837 |bibcode=2002JThBi.215..287B |citeseerx=10.1.1.405.1548 |ref=none}}
* {{cite book |last1=Sober |first1=Elliott |author1-link=Elliott Sober |last2=Wilson |first2=David Sloan |author2-link=David Sloan Wilson |year=1998 |title=Unto Others: The Evolution and Psychology of Unselfish Behavior |url=https://archive.org/details/untoothersevolut00sobe |url-access=registration |publisher=[[Harvard University Press]] |isbn=978-0674930476 |ref=none}}
* {{cite journal |last1=Soltis |first1=J. |last2=Boyd |first2=R. |last3=Richerson |first3=P. J. |year=1995 |title=Can Group-functional Behaviors Evolve by Cultural Group Selection? An Empirical Test |url=http://www.des.ucdavis.edu/faculty/richerson/SoltisBoydRichersonCA95.pdf |journal=[[Current Anthropology]] |volume=63 |issue=3 |pages=473–494 |doi=10.1086/204381|s2cid=43998139 |ref=none}}
* {{cite journal |last=Wilson |first=David Sloan |author-link=David Sloan Wilson |year=1987 |title=Altruism in Mendelian populations derived from sibling groups: The haystack model revisited |journal=[[Evolution (journal)|Evolution]] |volume=41 |issue=5 |pages=1059–1070 |jstor=2409191 |doi=10.2307/2409191|pmid=28563418 |ref=none}}
* {{cite book |last=Wilson |first=David Sloan |author-link=David Sloan Wilson  |year=2006 |chapter=Human groups as adaptive units: toward a permanent consensus |editor1=P. Carruthers |editor2=S. Laurence |editor3=S. Stich |title=The Innate Mind: Culture and Cognition |publisher=[[Oxford University Press]] |url-status=dead |archive-url=https://web.archive.org/web/20090226134728/http://evolution.binghamton.edu/dswilson/resources/publications_resources/DSW02.pdf |url=http://evolution.binghamton.edu/dswilson/resources/publications_resources/DSW02.pdf |archive-date=26 February 2009 |isbn=978-0195310146 |ref=none}}

==External links==

* {{IEP |url-id=altr-grp |title= Altruism and Group Selection |ref=none}}
* Lloyd, Elisabeth, [http://plato.stanford.edu/archives/fall2005/entries/selection-units/ "Units and Levels of Selection."] ''The Stanford Encyclopedia of Philosophy'', (Fall 2005 Edition), Edward N. Zalta (ed.)
* [http://www.scq.ubc.ca/?p=170 The Controversy of the Group Selection Theory] – a review from the "Science Creative Quarterly" (a [[blog]])
* [https://web.archive.org/web/20070715062538/http://evolution.binghamton.edu/dswilson/publications.html Binghamton: D.S. Wilson]

{{sociobiology}}
{{Evolution}}
{{evolutionary psychology}}
{{Eusociality}}
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{{DEFAULTSORT:Group Selection}}
[[Category:Selection]]
[[Category:Population genetics]]
[[Category:Extended evolutionary synthesis]]