A comparative investigation of the cognitive and social factors underlying a capacity for cumulative culture

Abstract

Human culture has been proposed to uniquely exhibit a ‘ratchet effect’, with beneficial modifications being made to cultural traits over many generations. This is widely thought to have allowed an accumulation of technology and knowledge over time, and to be of central importance to the remarkable ecological and demographic success of humans. Whilst many researchers argue that the roots of human culture lie in social learning, a process widespread in nature, the exact cognitive capacities that set humans apart are not known.

To provide a comparative assessment of nine separate hypotheses regarding different social and cognitive factors that may underlie a capacity for cumulative culture, in this thesis a cumulative puzzlebox was presented to three species. Groups of capuchins, chimpanzees and children were provided with the opportunity to solve the puzzlebox to three sequential levels to retrieve rewards of increasing desirability. Higher level solutions spread only in the children. Evidence was found for the occurrence of teaching, imitation, complex communication and prosociality in groups of children, but not in groups of capuchins and chimpanzees. Furthermore, these processes were positively correlated with the performance of individuals within the groups of children which was the only species to show evidence of cumulative cultural learning. Five further hypotheses focussed on alternative social and cognitive factors were not supported by the evidence from this experiment.