Figure 1.

The norm sensitivity hypothesis is based on an observation that since initiation of sedentary forms of living, people have organized their groups by certain patterns and norms of social behavior that are afforded and constrained by the forms of subsistence (e.g., farming different crops such as rice and wheat and herding different animals). Acquisition of these cultural patterns and norms is hypothesized to have been facilitated by certain polymorphic variants of dopaminergic (DA) system genes, including those of the dopamine D4 receptor gene (DRD4), that increase the dopamine signaling efficiency.