Thesis (Ph.D.) - University of St Andrews, November 2008.

The research aims of this thesis are to experimentally investigate how behaviours spread socially, and what factors contribute to the development of group-wide social traditions in capuchins (Cebus apella). Given the apparent convergent evolution between such monkeys and great apes, capuchin traditions are of great interest anthropologically and for a biological and psychological understanding of culture. Several studies have investigated social learning in capuchins, but few have made headway into understanding how it supports the development of traditions either in the wild or in captivity. By experimentally introducing novel foraging behaviours into several captive groups, the studies included in this thesis simulate the development of foraging behaviours so that their spread can be studied from various viewpoints. Five experiments are presented investigating: (1) the chained transmission of foraging behaviours, (2) the role of social facilitation on the rate of individual learning, (3) the fidelity of learning from localised stimulus enhancement & object-movement re-enactment, (4) the quality of individual relationships in the social transmission of novel foraging techniques, and (5) the open diffusion of group-specific foraging behaviours in capuchin monkeys. Together, these experiments explore how traditions may develop, ranging from individual learning to how behaviour patterns may spread socially based on social ties within the group.