Much of the discussion regarding group selection has been fueled by its fuzziness for many, yet the appeal to many of holy-grail, single-process explanations for human social behaviors. Steven Pinker’s essay is provocative and as such important in educating readers, but I believe that he is incorrect in applying Occam’s razor to say that simpler, ground level, individual selection is sufficient to explain traits in human groups. There are counter-arguments that selection on different levels is involved (or as I argue below, was involved) in the establishment of behavioral and institutional adaptations.
Challenge – Signal – Response. In understanding the origin and current relevance of group traits, one must consider the context in which they are elicited, the elicitor, context-dependent signals between individuals, and their behavioral responses. Take for example feelings of patriotism, elation, and resolve when in a like-minded group, hearing and singing one’s national anthem and seeing one’s national flag raised. These unifying signals elicit emotional and physiological responses (e.g. adrenaline secretion). What for? Those groups that more effectively react to challenges will tend to survive and spread, even if the precise signal is altered, for example, when colonizing a new habitat (e.g., the colonizers may invent a new anthem and new flag, but have the same group level traits). What counts is whether the specific stimulus and response are shared by many or most members of a given group, and whether their evocation changes the prospects of group survival, growth and spread.
Group Traits: Memes, Genes and Institutions. Group selected traits may have either a cultural and/or genetic basis. Although there is not perfect equivalence between the two, both function in similar and sometimes complementary ways. “Culture” is one of the defining characteristics of human groups, but that it is not a one-off occurrence is vouched by one important aspect of culture—tool use—in other primates, mammals, and even some birds and cephalopods. The question is whether group traits in humans depend only on individual minds though social learning and to what extent our genetic material gives us proclivities towards prosocial behaviors. For example, why would groups with higher proportions of altruistic punishers tend to win-out over those with fewer? Or, rather, do certain individuals only stand to benefit from this and other similar social behaviors? The answer is likely to depend on context (see below). But the key reason why our minds (individual and collective) and DNA retain the seeds of such adaptations and for why emergent features such as social norms and institutions exist at the group level are that those groups which effectively coordinate and communicate tend to survive, grow, and spread. This does not necessarily mean that all social behaviors are for mutual benefit or the good of the group! Rather, those groups that tend to have higher frequencies of these behaviors tend to win out over those that do not.
Origins. Why do some people actually volunteer to be in armies, help others in distress risking (whether aware or not) their own possible injury, politely open doors for others, etc.? More innocuously, why do people enjoy sporting events and fervently support the home team? All of these behaviors seem at odds with individually selected adaptations in today’s world, and they also may very well appear to be at odds with the process of group selection. The likely reason for why is that many or most group traits originated in small, hunter-gatherer groups. Such traits may still be under selection, but are evoked in (slightly) different contexts to those in which they were originally selected. At the time when these traits were originally selected, if you asked someone to identify herself, then she may have given you her name, her tribe’s name and her function within the tribe. That is, units of selection were few and distinct. Today, she might give you her name, city and state of birth, country, religion, club membership, profession, etc. This is one possible reason for why selection for group traits will be slower and more transient today than in the distant past. Indeed, it is possible that many group-level traits no longer evolve; they are the fittest decedents of past.
Michael E. Hochberg, SEF Editor-in-Chief
Choi J.K. & Bowles S. 2007. The coevolution of parochial altruism and war. Science 318: 636-640.
Danchin É. et al. 2011. Beyond DNA: integrating inclusive inheritance into an extended theory of evolution. Nature Reviews Genetics 12: 475-486.
Gintis H. 2012. The evolution of human cooperation. Social Evolution Forum. http://socialevolutionforum.com/2012/01/11/the-evolution-of-human-cooperation/
Hochberg M.E. et al. 2003. Socially mediated speciation. Evolution 57: 154-8.
Wiltermuth S.S. & Heath C. 2009. Synchrony and cooperation. Psychol Sci 20:1–5.
Group vs individual seems like a straw-man framing of the issue. It’s group vs individual plus kin. We now know that these two approaches make the same predictions – e.g. see my “Group selection and kin selection are formally equivalent” article. So, its down to ease of use, ease of visualisation, familiarity, fit for your problem domain, etc.
individual+kin = group