The emerging trend is that we let go of the idea that humans are naturally endowed with “rationality” (especially in the sense of consistency and utility maximization, as in microeconomic) in favor of an evolutionary view in which the brain evolved together with the affordances and problems offered by living in larger groups. Rather than seeing humans as having evolved to pursue their self-interest in a utility maximizing way, what is emerging is to see humans as having evolved to draw adaptive advantage from living in larger groups by a set of self-regulatory abilities (some of which are more or less automatic and can be overridden by less automatic capabilities). The self-regulatory abilities, in turn, can vary and are much dependent on the social environment. For example, having significant others is vital for one's self-regulatory ability, as is the capacity to change one's environment in order to strengthen one's self-regulatory capacity. The sociologically interesting part of all this is exactly this social dependence of self-regulatory capacity. Rationality, if that term would still be used, is thus thoroughly a matter of person by environment interaction. This has fundamental consequences for how social science is done.