Cultural group selection plays an essential role in explaining human cooperation: a sketch of the evidence.

In the paper

“Consistent with the hypothesis that individual variation for many normative beliefs and behaviors is small within groups and large between groups, we find large betweengroup differences among all groups of all scales (Fig. 1).”

In the paper

“Our data reach well into the plateau of the L-shaped region of the group selection condition.”

In the paper

“The results (Fig. 1A) show that the extent of allomaternal care directed at immatures is the best predictor of experimentally assessed proactive prosociality within a group, far better in fact than any other factor proposed so far, including brain size, social tolerance, cooperative hunting, or the presence of strong social bonds.”

What the sources say

• Not checked yetcites Burkart et al. 2014

In the paper

“perceive a greater degree of external threat, reflected in the desire for more national defense spending and greater rates of military recruitment, as compared to loose states.”

What the sources say

• Not checked yetcites Harrington and Gelfand (2014)

In the paper

“Under low threat, the evolutionary pressures resulted in a more diverse mix of all possible strategies.”

In the paper

“evolutionary game theoretical (EGT) models show that groups that face a high degree of threat require stronger norms and greater punishment of deviance in order to survive (Roos et al. 2015).”

What the sources say

• Not checked yetcites Roos et al. 2015

In the paper

“and supported more isolationist policies (such as buying American products exclusively and supporting government restriction of imported products) compared to loose states.”

What the sources say

• Not checked yetcites Harrington and Gelfand (2014)

In the paper

“fewer resources (indicated by greater rates of food insecurity)”

What the sources say

• Not checked yetcites Harrington and Gelfand (2014)

In the paper

“a greater incidence of disease and health vulnerabilities”

What the sources say

• Not checked yetcites Harrington and Gelfand (2014)

In the paper

“Tighter states also had significantly lower residential mobility”

What the sources say

• Not checked yetcites Harrington and Gelfand (2014)

In the paper

“Field research across 33 nations first documented the connection between ecological and historical threat and the degree of norm strength in groups (Gelfand et al. 2011).”

What the sources say

• Not checked yetcites Gelfand et al. 2011

In the paper

“and lower openness”

What the sources say

• Not checked yetcites John et al. 2008

In the paper

“we tested this hypothesis across a wide range of variables and found that societies facing ecological and historical threats do indeed develop stronger norms and punishment of deviance (Gelfand et al. 2011).”

What the sources say

• Not checked yetcites Gelfand et al. 2011

In the paper

“Individuals in tighter states also had higher levels of conscientiousness”

What the sources say

• Not checked yetcites John et al. 2008

In the paper

“Initial results from our broad-scale assessment of these data indicate support for Richerson et al.'s assertion that CGS was active “as far back as symbolic marking is evident.””

In the paper

“these models also found that temporary increases in threat cause norm strength to increase until the threat subsides.”

In the paper

“Roach et al. (2013) showed that Homo erectus had already evolved this capacity for accurate overhead throwing.”

What the sources say

• Not checked yetcites Roach et al. (2013)

In the paper

“Among foragers in Indonesia, field studies show that patriclan membership predicts large-scale cooperation in whale hunting better than genealogical kinship (Alvard 2011).”

What the sources say

• Not checked yetcites Alvard 2011

In the paper

“First, petkeeping occurs in humans only.”

What the sources say

• Not checked yetcites Herzog 2014

In the paper

“the fact that long-term affectionate relationships between non-conspecifics have not been observed in the wild, even in nonhuman apes”

In the paper

“A recent study found that mothers who had pets in their childhood, tended to raise their offspring with pets (Westgarth et al. 2010).”

What the sources say

• Not checked yetcites Westgarth et al. 2010

In the paper

“Cross-cultural studies reveal that practices common in modern Western societies, such as letting animals live in our homes, allowing them to sleep in our beds, and considering them full-fledged family members are cultural anomalies (Gray & Young 2010).”

What the sources say

• Not checked yetcites Gray & Young 2010

In the paper

“are unrelated to breed-characteristic qualities such as desirable behavioral traits and frequency of genetic diseases (Ghirlanda et al. 2013)”

What the sources say

• Not checked yetcites Ghirlanda et al. 2013

In the paper

“Europeans were more likely to introduce extractive colonial regimes in relatively richer societies or regions where they could not settle.”

What the sources say

• Not checked yetcites Acemoglu et al. 2001
• Not checked yetcites Acemoglu et al. 2002

In the paper

“The culture of honor within high castes in India is related to a low degree of coordination (Brooks et al. 2014).”

What the sources say

• Not checked yetcites Brooks et al. 2014

In the paper

“On the multi-ethnic island of Sri Lanka, 79% of Buddhist households include a dog, compared to Muslim households, of which only 4% do (Knobel 2009).”

What the sources say

• Not checked yetcites Knobel 2009

In the paper

“Sudden shifts in the popularity of types of pets occur across cultural groups via social transmission.”

In the paper

“long-lasting changes in the popularity of types of dogs are sometimes instigated by media exposure (films with canine movie stars) (Ghirlanda et al. 2014).”

What the sources say

• Not checked yetcites Ghirlanda et al. 2014

In the paper

“We have found that dog breed preferences are influenced by the decisions of others (Herzog et al. 2004)”

What the sources say

• Not checked yetcites Herzog et al. 2004

In the paper

“A series of empirical field studies I conducted in rural India demonstrate that: (1) individuals do not exhibit a strong tendency to culturally transmit cooperative behaviour (Lamba 2014);”

What the sources say

• Not checked yetcites Lamba 2014

In the paper

“A series of public goods games, played with real money and for high stakes, across these populations found little evidence that people used either pay-off biased learning or conformity to copy others' cooperative behaviour.”

What the sources say

• Not checked yetcites Lamba 2014

In the paper

“However the beliefs and values examined are not associated with actual cooperative behaviours; for example, demonstrating that there is significant country-level variation in attitudes toward abortion has arguably little relevance to the argument at stake.”

In the paper

“We found that individuals took more salt for themselves and left less for others in larger villages (Lamba & Mace 2011).”

What the sources say

• Not checked yetcites Lamba & Mace 2011

In the paper

“(2) behavioural variation observed across human groups is at least in part driven by demographic and ecological processes rather than cultural processes (Lamba & Mace 2011;2012;2013);”

What the sources say

• Not checked yetcites Lamba & Mace 2011;2012;2013

In the paper

“Our attempts at testing this hypothesis for the evolution of parochial altruismthe combination of in-group altruism and out-group hostility due to intergroup competition and conflictusing naturalistic field experiments in Northern Ireland, found little evidence to support this idea.”

What the sources say

• Not checked yetcites Silva & Mace 2014;2015

In the paper

“For example, the historical pattern for the appearance and spread of kinship terminologies as part of the colonization of the Pacific Oceanic Islands, first by Melanesians and then by Polynesians, can be presented as a phylogeny organized around structural differences in the terminologies (Read 2013; see Fig. 1 here).”

What the sources say

• Not checked yetcites Read 2013

In the paper

“Their adaptation included a culturally prescribed system of sealing partners central to procuring and sharing seal meat in the winter months.”

What the sources say

• Not checked yetcites Balikci 1970

In the paper

“We found significant differentiation between groups with an average Φ ST of 0.091, indicating that, on average, 9.1% of the variation between individual folktales was between groups”

In the paper

“However, incorporating geography into the analysis revealed that at the level of individual folktales, geographic distance explains considerably more variation between folktales than group boundaries (6.6% of variance vs. 3.7%).”

In the paper

“None of the 29 cultural F ST estimates reported by Richerson et al. or the cultural F ST estimates reported by Bell et al. (2009) have been analysed within a spatially explicit framework.”

In the paper

“which is considerably higher than the genetic differentiation found between comparable European populations (Lao et al. 2008;Novembre et al. 2008).”

What the sources say

• Not checked yetcites Lao et al. 2008
• Not checked yetcites Novembre et al. 2008

In the paper

“Despite these limitations, we maintain that our cultural F ST estimates provide readily available evidence that between-group variation is sufficient for selection to act at the group level (Rogers 1990).”

What the sources say

• Not checked yetcites Rogers 1990

In the paper

“A CGS framework is based on the empirical data strongly suggesting that heritable cultural variation often exists between groups at scales larger than groups linked by kinship or a history of reciprocation (target article, sect.4).”

In the paper

“Ethnographic evidence from hunter-gatherer societies suggests that our Late Pleistocene ancestors already had many interactions with non-kin that were regulated by systems of norms and institutions, even in societies numbering only a few hundred to a few thousand (Hill et al. 2014).”

What the sources say

• Not checked yetcites Hill et al. 2014

In the paper

“We provide a guide to the relevant theory and argue that the empirical evidence from a range of domains provides robust qualitative support for the point that CGS describes real and important processes in human social evolution.”

In the paper

“Two of these forms are driven by human choiceschoices in part based on prosocial emotions like Darwin's sympathy and patriotism.”

In the paper

“The CGS hypothesis is thus vulnerable to disproof in several empirical domains.”

In the paper

“First, evidence from developmental studies shows how a cognitive system for imitation arises in the first 12 months of life and dovetails with adult behaviors that support children's social learning.”

In the paper

“Docile individuals more inclined to conform to norms would find it easier to enter larger more norm-bound groups and hence be able to acquire more sophisticated technology (Simon 1990).”

What the sources say

• Not checked yetcites Simon 1990

In the paper

“If the payoff to any strategy depends on the local frequency of its use, then even subpopulations in identical environments may reach different stable equilibria over time.”

What the sources say

• Not checked yetcites Cooper 1999

In the paper

“The complexity of technology that a group can maintain is a function of its size (Henrich 2004;Shennan 2001).”

What the sources say

• Not checked yetcites Henrich 2004
• Not checked yetcites Shennan 2001

In the paper

“Second, historical evidence shows that human culture exhibits a phylogenetic pattern of descent with modification in which ancestral commonalities can be traced back thousands of years.”

In the paper

“If neutral marker traits correlate with behavioral norms that are difficult to observe, then selection may favor attentiveness to these markers as reliable signals of whom to imitate (McElreath et al. 2003).”

What the sources say

• Not checked yetcites McElreath et al. 2003

In the paper

“Genome-wide scans for genes under selection and comparative studies on chimpanzee-human differences detect strong recent selection at a large number of loci affecting genes that are expressed in the nervous system and in hormone producing glands.”

What the sources say

• Not checked yetcites Laland et al. 2010
• Not checked yetcites Ross & Richerson 2014

In the paper

“Other apes have a much more rudimentary social learning system.”

In the paper

“This provides a relatively slow form of selection for traits that contribute to group success (Soltis et al. 1995).”

What the sources say

• Not checked yetcites Soltis et al. 1995

In the paper

“As we discuss below, selection on tribes can account for the innate foundation of our social psychology via the process of gene-culture coevolution.”

In the paper

“The best understood examples of culture-led gene-culture coevolution are adult lactase persistence (Durham 1991) and the hemoglobin polymorphisms that confer resistance to malaria (Allison 1964).”

What the sources say

• Not checked yetcites Durham 1991 source
• Not checked yetcites Allison 1964

In the paper

“Human cognition includes adaptations for imitation and teaching that allow the cumulative evolution of complex traits, including norms and institutions that regulate social behavior (Tomasello 1999).”

What the sources say

• Not checked yetcites Tomasello 1999

In the paper

“While modern nations and the subgroups of which they are composed differ in many ways from ancestral tribes, they rest on the innate foundations that evolved from competition between ethnolinguistic units (Richerson & Boyd 1999).”

What the sources say

• Not checked yetcites Richerson & Boyd 1999

In the paper

“Punishment of those who engage in uncommon behaviors can stabilize essentially any norm within a group, regardless of its other adaptive consequences (Boyd & Richerson 1992b).”

What the sources say

• Not checked yetcites Boyd & Richerson 1992b

In the paper

“It is also difficult to see how the developmental and historical evidence can be reconciled with an extreme version of the later improvisational intelligence hypothesis of Cosmides and Tooby (2001).”

What the sources say

• Not checked yetcites Cosmides and Tooby 2001

In the paper

“Moral norms that evolved under the influence of CGS would exert social selection on human genes via mechanisms such as selective child neglect, mate choice, and punishment (Feldman & Laland 1996;Newson 2013).”

What the sources say

• Not checked yetcites Feldman & Laland 1996
• Not checked yetcites Newson 2013

In the paper

“Humans exhibit a wide variety of culturally transmitted organizational phenomena larger than, and different from, those reflecting biological relatedness and close pairwise partnerships.”

In the paper

“Two quite distinct lines of evidence show that human culture acts as an inheritance system.”

In the paper

“Over repeated rounds of such coevolution, stretching back perhaps several hundred thousand years, our Pleistocene ancestors came to have institutionalized social systems with (if ethnographic analogs are reliable) complex sets of linked norms organizing tribal societies of a few hundred to a few thousand people (Hill et al. 2014).”

What the sources say

• Not checked yetcites Hill et al. 2014

In the paper

“The functioning of complex institutions is highly dependent on tacit knowledge (Aoki 2001).”

What the sources say

• Not checked yetcites Aoki 2001 source

In the paper

“A recent quantitative estimate of rates of cultural evolution using a large body of historical and archaeological data showed that it evolves considerably faster than genes (Perreault 2012).”

What the sources say

• Not checked yetcites Perreault 2012

In the paper

“Children have powerful cognitive systems evolved to acquire quite complex cultural knowledge from their elders.”

In the paper

“This favors the spread of group-beneficial norms and institutions (Boyd & Richerson 2002).”

What the sources say

• Not checked yetcites Boyd & Richerson 2002

In the paper

“The direct effect of environments was strongest on economy-related traits and medium to low on other traits.”

What the sources say

• Not checked yetcites Guglielmino et al. (1995)

In the paper

“The effect of horizontal diffusion was high on the division of labor by sex and house type.”

What the sources say

• Not checked yetcites Guglielmino et al. (1995)

In the paper

“The same basic system seems to operate across all domains of culture (Harris 2012).”

What the sources say

• Not checked yetcites Harris 2012

In the paper

“From the correspondence of linguistic time-depth estimates and archaeological dates, each of these language families appears to constitute a cultural adaptive radiation based upon agricultural subsistence and associated social-organizational features.”

In the paper

“Again, this is a necessary but not sufficient condition for CGS to have been an important process.”

In the paper

“Such studies show that features of social organization often include strong phylogenetic signals that are correlated with the linguistic signal.”

In the paper

“However, over-imitation is probably an essential adaptation for building a repertoire of elementary skills and maneuvers that will eventually be incorporated into complex crafts and social institutions (Harris 2012).”

What the sources say

• Not checked yetcites Harris 2012

In the paper

“These innovations allowed their speakers to expand at the expense of hunter-gatherers in the Early and Middle Holocene.”

In the paper

“In other words, the effect of either vertical or horizontal transmission was strong on all traits examined.”

In the paper

“Many cultural adaptations are so complex that the functional significance of many elements of them is opaque to learners and often to accomplished practitioners as well.”

In the paper

“The transmission of complex cultural information and its cumulative evolution requires accurate imitation (Tennie et al. 2009).”

What the sources say

• Not checked yetcites Tennie et al. 2009

In the paper

“Most grammatical constructions appear to be cultural features underpinned only indirectly by rather general cognitive features (e.g., Hurford 2011).”

What the sources say

• Not checked yetcites Hurford 2011

In the paper

“Human children routinely learn concepts with help from knowledgeable others that qualitatively transcend innate intuitions (Carey 2009).”

What the sources say

• Not checked yetcites Carey 2009

In the paper

“Thus, studies of child development strongly suggest that human social learning does accurately transmit cultural variants over a wide range of design space in many domains (Carey 2009).”

What the sources say

• Not checked yetcites Carey 2009

In the paper

“Human social learning contrasts sharply with that of chimpanzees and other nonhuman animals.”

In the paper

“Adults and knowledgeable children also appear to be adapted to behave in ways that scaffold the learning of naïve children (Csibra & Gergely 2011;Dean et al. 2012;Kline 2015).”

What the sources say

• Not checked yetcites Csibra & Gergely 2011
• Not checked yetcites Dean et al. 2012
• Not checked yetcites Kline 2015 source

In the paper

“The Walker et al. study is notable for quantitatively estimating rates evolution in several Tupi cultural domains (usually less than five transitions in 10 millennia).”

What the sources say

• Not checked yetcites Walker et al. 2012

In the paper

“Carefully following demonstrated recipes preserves functionality, albeit at some cost of replicating non-functional elements.”

In the paper

“The phylogenies of several large language families have been investigated, including Bantu (Holden 2002), Austronesian (Gray et al. 2009), Tupi (Walker et al. 2012), and Indo-European (Bouckaert et al. 2012).”

What the sources say

• Not checked yetcites Holden 2002
• Not checked yetcites Gray et al. 2009
• Not checked yetcites Walker et al. 2012

In the paper

“The second-best-fitting model allowed for decreases (but not increases) in complexity to skip intermediate steps.”

What the sources say

• Not checked yetcites Currie et al. (2010)

In the paper

“They found that in the best-fitting model, political complexity increased and decreased in incremental steps.”

What the sources say

• Not checked yetcites Currie et al. (2010)

In the paper

“If adults suggest that it is important, children will replicate adult actions in ritualistic detail (Herrmann et al. 2013).”

What the sources say

• Not checked yetcites Herrmann et al. 2013

In the paper

“In comparative studies with human children, chimpanzees tended to imitate only the behaviors necessary to reach a goal, while children diligently imitated all of an adult's behaviors whether or not they directly resulted in reaching a tangible goal (Whiten et al. 2009).”

What the sources say

• Not checked yetcites Whiten et al. 2009

In the paper

“Early farmers in Europe were clearly the result of a demic expansion (Haak et al. 2010).”

What the sources say

• Not checked yetcites Haak et al. 2010

In the paper

“Social norms are among the cultural traits that children readily acquire from adults and other children.”

In the paper

“Traits with some detrimental individual-level effect on reproduction and/or survival can also be favored if group benefits are sufficiently large to satisfy the inequality.”

In the paper

“The large cultural differences measured in this analysis suggest a wide scope for CGS.”

In the paper

“The effects of out-group discrimination and in-group preference based upon cultural categories like race are evident as early as 3 years of age, when children begin to implicitly associate same-race faces with positive facial expressions and different-race faces with negative facial expressions (Hugenberg & Bodenhausen 2004).”

What the sources say

• Not checked yetcites Hugenberg & Bodenhausen 2004

In the paper

“In section 2.1 we reviewed the mechanisms by which cultural systems can preserve much more variation between groups of unrelated or distantly related individuals than can genetic inheritance.”

In the paper

“The more groups differ, the more effective CGS is likely to be.”

In the paper

“By the time people are adults, much experimental work by social identity theorists shows that, in many social situations, individuals' behavior is substantially influenced by their affect-laden social group identifications (Haslam 2001).”

What the sources say

• Not checked yetcites Haslam 2001

In the paper

“Our average measurements of cultural F ST place the group-benefit-to-cost requirement well within range of some important cultural behaviors.”

In the paper

“Bell et al. (2009) compared cultural F ST from the World Values Survey with genetic F ST from Cavalli-Sforza et al.'s (1994) classic study.”

What the sources say

• Not checked yetcites Bell et al. (2009)
• Not checked yetcites Cavalli-Sforza et al.'s (1994)

In the paper

“Social learning biases, such as those described previously, act as a general force adapting culture to local environments.”

In the paper

“These data suggest that the scope for CGS is substantially higher than for genetic group selection.”

In the paper

“This relationship suggests that evolutionary forces that create relatively small differences between similar groups can provide some scope for group selection in cases where group benefits are high relative to costs.”

In the paper

“These values are important, as small increases in cultural F ST beyond 0.01 increase the possibility for CGS dramatically.”

In the paper

“Note that the scope for group selection is sensitive to changes in low values of F ST , because the minimum condition declines geometrically with a linear increase in F ST .”

In the paper

“Even very young children prefer teachers and social partners who belong to their own social group.”

In the paper

“The accurate imitation of cultural variation, especially group identities and social norms, is the basis for heritable cultural variation between groups upon which CGS can act.”

In the paper

“The Price equation, a general depiction of selection operating on multiple levels, can be re-arranged to express the required conditions for a group-beneficial trait to be favored by selection in the face of individual-level selection against the trait (Bell et al. 2009;Bowles 2006):”

What the sources say

• Not checked yetcites Bell et al. 2009
• Not checked yetcites Bowles 2006

In the paper

“Not all potential providers of social learning are equal.”

In the paper

“Young children are strikingly inflexible with social norms and rules, resulting in young moral absolutists (Levy et al. 1995).”

What the sources say

• Not checked yetcites Levy et al. 1995

In the paper

“Chimpanzees' abilities in this regard are more limited (Warneken & Tomasello 2009).”

What the sources say

• Not checked yetcites Warneken & Tomasello 2009

In the paper

“Human children are also motivated to engage with others to pursue a shared goal without any reward, apart from the enjoyment of engaging with another person socially (Tomasello & Carpenter 2007).”

What the sources say

• Not checked yetcites Tomasello & Carpenter 2007

In the paper

“Aside from a few cases (e.g., Edgerton 1971), computing cultural F ST from ethnographic data is not possible because most ethnographers studying simple societies report only normative behavior and neglect individual variation.”

What the sources say

• Not checked yetcites Edgerton 1971

In the paper

“Attempts to raise chimpanzee infants as if they were children are unsuccessful because young chimpanzees rather quickly mature into independent individuals that are not very responsive to being taught social norms, much less adopting them spontaneously (e.g., Hayes 1951).”