The past few decades have seen bad blood between biologists and social scientists. Each camp has seen social evolution as its own preserve: the biologists confident that evolutionary biology would deliver insights about culture and social behaviour; the social anthropologists, psychologists, and linguists resenting intrusion on to what they have seen as their patch. The two groups have fiercely debated questions about genes and culture: how behaviour is transmitted from one generation to another, where language comes from and how it is learnt. This report summarises a meeting organised by The Royal Society which attempted to bring the two sides together. It set out to discuss how far the emergence of new patterns of behaviour represents learning or results from genetically transmitted mechanisms; how cognitive development interacted with social organisation during critical transitions in human evolution; how far primates have culture but not language; and when, and how, language itself developed in human but not other primate species.