Popular Delusions: How Social Conformity Molds Society and Polit ...

Indeed, nonhuman primates exhibit norms such as fairness or reciprocity,¹¹ and chimpanzees are somewhat conformist in small groups. But other species have never developed the rich variety of cultures that humans have with their complex social customs passed down from one generation to the next. To explain conformity in human culture as the result of evolution requires a model of the emergence and survival of conformity as an inherited trait. Such a model must explain what advantage conformity has given to humans in the face of natural selection.

Human evolution is not something to study in a lab, but one can use mathematical models to test theories, as Joe Heinrich and Robert Boyd have done. In their model, conformity transmission means that individuals preferentially adopt the most common cultural traits in a population. These traits, in turn, are tested and selected by their success in helping people meet environmental challenges. Humans can learn how to deal with their environment either from other people, as by conformity or other social learning, or by individually adapting to the environment. Their model initially assumes that very few people in a population have a genetic trait for conformity and that most learning is done individually. Computer simulations with the model then explore what happens over many generations. The model builds in several stages within each generation: genetic transmission and variation, cultural transmission including social conformity and other social learning, individual learning, migration among social groups, and natural selection. By varying the strength of these factors in the mathematical model, the researchers estimate how likely conformity genes will prevail genetically and what the net results are on human populations.

The model shows that even if conformity starts out as a rare genetic trait, it ends up as a dominant characteristic; this type of social learning helps people survive environmental challenges. Another finding is that conformity genes lead to distinct human groups with different cultures and strong social boundaries between groups—social differences that are a potential source of conflict. On the positive side, conformity transmission increases the accuracy of social learning and reliance on social learning in groups, so long as the environment does not change too rapidly; in that case individualistic learning is more valuable in evolution.