Figure 2: The relationship between biological evolution and cultural change. (a) Sociobiology: Culture is treated as the expression of naturally selected genes, like any other feature of the phenotype. (b) Gene-culture coevolutionary theory: Culture is treated as shared ideational phenomena (ideas, beliefs values, knowledge), that are learned, and socially transmitted between, as a cultural inheritance. Cultural activities may modify some natural selection pressures in human environments, and thereby bias the transmission of some selected human genes. (c) Extended gene-culture coevoutionary framework: Niche construction from all ontogenetic processes modify human selective environments, generating a legacy of modified natural selection pressures which are bequeathed by human ancestors to their descendants. This figure best captures the causal logic underlying the relationship between biological evolution and cultural change.