Why the human brain is not an enlarged chimpanzee brain

Following Darwin, many comparative psychologists assume that the human mind is a kind of ape mind, differing only in degree from the extant apes - we call this the mental continuity assumption. However, the continuity principle in evolutionary theory does not posit continuity between extant closely related species, but between extant species and their extinct ancestors. Thus, it is possible that some human cognitive capacities have no parallels in extant apes, but that they emerged in extinct hominid species after the human-chimpanzee divergence. Our examination of the case of social cognition from an archaeological and comparative psychological perspective suggests that the human brain is not simply an enlarged chimpanzee brain. Instead, natural selection seems to have favoured a different social cognition in both species.