Whither evolutionary psychology?



Is groupthink genetically determined? Twin studies suggest that people are prewired to identify and comply with social rules.



Where to from here? Will evolutionary psychology ossify and disappear? Or will it redefine itself and move on?



In a sense it doesn’t matter. A name is just a name, and the field of evolution and human behavior has had other names. The main issue is whether the current name is a help or a hindrance. Will it allow change from within?



Bolhuis et al. (2011) think so. In their call for a new evolutionary psychology, they have made several recommendations. One is to accept the reality of gene-culture co-evolution. In short, we should pick up where research petered out some two decades ago.



Amongst the overrepresented categories in genome-wide scans of recent selection are numerous alleles expressed in the human nervous system and brain. This raises the possibility that complex cognition on which culture is reliant (social intelligence, language, and challenges associated with constructing and adapting to new environmental conditions) have driven human brain evolution. Mathematical models exploring how genetic and cultural processes interact provide strong support for the role of gene-culture coevolution in human evolution.



Evolutionary psychologists should reconsider their assumption of a universal human nature. “For example, sex differences in mate preferences constitute a large proportion of EP research and are generally assumed to exhibit universal patterns.” Yet sex roles assume different forms in different human populations.



Another recommendation is to bridge the gap between postulated “psychological mechanisms” and actual neurons. We now have tools, notably MRI, that can locate where a specific mental activity occurs in the brain. Again, such research should take variation within and between human populations into account and not be confined to the usual participant pool of North American university students.



Finally, evolutionary psychologists should stop assuming that the human mind consists mainly of domain-specific programs. Much of our thinking is, in fact, domain-general.



Uh, what is ‘domain-general’? Think of a computer program that has plenty of sections or variables left blank. The blanks can be filled in with information, thus enabling the same kind of program to do a wide range of tasks. We call this in-filling process ‘learning.’



Learning thus takes place via programs that have already been partly hardwired. This is why we can learn some things better than others. There are also constraints on how fast we can learn, how much we can learn, and on how easily we can integrate learned information. Learning is not the opposite of genetic determinism. The two concepts are complementary.



By minimizing the role of learning, evolutionary psychologists not only lose the high ground of credibility but also give a free hand to those who say that humans can learn to think anything. A good example is the debate over social rules:



EP has engaged in a longstanding debate with advocates of cultural evolution over whether human social learning is governed by evolved content biases (e.g., choose the sugar-rich food) or by domain-general context biases (e.g., conform to the local norm). There is sufficient empirical evidence for the deployment of context biases, such as conformity or prestige bias, to render the casual dismissal of transmitted culture counterproductive. (Bolhuis et al., 2011)



Groupthink is a reality, and its persistence in modern societies should make it ideal for EP research. One puzzle of twin studies is the relatively high heritability of religious fundamentalism. Among twins reared apart, 40-46% of the variance seems to be genetic in origin (DiLalla et al., 1996). Perhaps there has been natural selection for humans who can more easily identify and comply with social rules, thus sparing themselves the pain of learning them the hard way.



This point is worth investigating because willingness to comply with rules varies from one individual to another, and from one population to the next. Some people have an unusually high level of rule compliance. Why? Is it learned or innate? Or a bit of both?



Some evolutionary psychologists have actually been moving in this direction. Denise Cummins (1998, p. 37) describes mental evolution as “a strategic arms race in which the weaponry is ever-increasing mental capacity to represent and manipulate internal representations of the minds of others.” In addition to ‘indicative reasoning’ (what is true or false), humans have a capacity for ‘deontic reasoning’ (what is permitted, obligated, or forbidden). For deontic rules, people look for examples of violations. For indicative rules, people look for examples of proof.



In short, indicative rules are subject to change, as people learn more about their environment. Deontic rules are not so easily changed. The latter generally change with a new class of higher-status individuals, who not only are the preferred source of deontic rules but are also seen as being above the rules. Thus, people more easily remember cheaters than non-cheaters, but this memory is weaker when the cheaters are high-status individuals (Mealey, Daood, & Krage, 1996).



All of this raises a problem for the Pleistocene EEA. Hunter-gatherer societies have little if any social stratification. The same is largely true for simple agricultural societies. The ‘big man’ is not a force for social stability and rule making. His dominance is transient, lasting as long as his strength, charisma, and ability to intimidate.



Societies became stratified only during the last 10,000 years. This time also saw the beginnings of lawmaking, codified morality, and organized religion. Of course, there is no reason why these phenomena could not have influenced human nature via gene-culture co-evolution. The last 10,000 years have seen more genetic evolution than the previous 100,000 … or even the previous million.



But to say so is anathema to those who still believe that the human mind stopped evolving over a million years ago.



References



Bolhuis, J.J., G.R. Brown, R.C. Richardson, and K.N. Laland. (2011). Darwin in mind: New opportunities for evolutionary psychology, PLoS Biol 9(7): e1001109. doi:10.1371/journal.pbio.1001109

http://www.plosbiology.org/article/info:doi/10.1371/journal.pbio.1001109



Cummins, D.D. (1998). Social norms and other minds: The evolutionary roots of higher cognition. In D.D. Cummins & C. Allen (eds.) The Evolution of Mind (pp. 30-50). New York: Oxford University Press.



DiLalla, D.L., G. Carey, I.I. Gottesman, and T.J. Bouchard Jr. (1996). Heritability of MMPI personality indicators of psychopathology in twins reared apart, Journal of Abnormal Psychology, 105, 491-499.



Mealey, L., C. Daood, & M. Krage. (1996). Enhanced memory for faces of cheaters, Ethology and Sociobiology, 17, 119-128.