PhD ceremony Mr. L.S. Molleman: Social learning and human cooperation

PhD ceremony: Mr. L.S. Molleman

Dissertation: Social learning and human cooperation

Promotor(s): prof. F.J. Weissing

Faculty: Mathematics and Natural Sciences

In his PhD thesis Lucas Molleman shows experimentally that individuals differ in their social learning strategies, and that they tend to employ the same learning strategy irrespective of the social situation they find themselves in. Payoff-based learners focus on their peers’ success, while decision-based learners disregard payoffs and exclusively focus on their peers’ past behaviour. He also shows that these individual differences in social learning strategies are stable over longer periods of time. This suggests that social learning strategies can be viewed as personality traits as studied by psychologists.

By means of mathematical models and individual-based simulations, Molleman shows that variation in social learning strategies can make groups cooperate more efficiently. Additional models show that, in contrast to a widely held view in the literature, ‘cultural evolution’ – through social learning – does not generally lead to more cooperation than genetic evolution. With further experiments he investigated how cooperation between people can be supported by reciprocity (‘I help you, then you help me later’). People have different reasons to cooperate with others: for some, direct interactions with a partner are most important, but others generally focus on their partner’s reputation. Theory suggests that stable cooperation is promoted if the punishment of non-cooperators leads to a better reputation, but Molleman’s experiments suggests that only a minority of people reward such punishment behaviour.