1. Robert Rowthorn Economics Faculty Cambridge University

2. Recent Work Rowthorn, “The Evolution of Altruism between Siblings” (Journal of Theoretical Biology 2006) – Population Genetics Guzman, Rodriguez and Rowthorn, “When in Rome do as the Romans Do: The Co-evolution of Altruistic Punishment, Conformist Learning and Cooperation “ (Evoluton and Human Behavior 2007) – Evolution of Learning Rules, Simulation Rowthorn and Sethi, “Procedural Rationality and Equilibrium Trust” (forthcoming Economic Journal) – Mathematical Learning Models

3. Group Size & Hierarchy In our E&HB paper, group size was exogenous. Our aim is to make group size endogenous. We are currently examining the relationship between technology, group size and hierarchy. There is a big anthropological literature, but little formal modelling. We are reading the literature and have begun the modelling.

4. Forms of Social Interaction In our E&HB paper we considered the interaction between learning strategies (conformism and profit-seeking) and social behaviour (cooperation, punishment, defect). We propose to examine other issues, for example, coordination or distribution problems.

5. Migration and Assimilation The benefits of cultural diversity may be offset by communication difficulties and parochial loyalties. Groups may gain competitive advantage if they limit diversity by restricting immigration or promoting assimilation. The evolution of such social mechanisms may have genetic counterparts in the form of a high propensity to conform or a high propensity towards xenophobia. In our E&HB paper we considered some of these issues. We intend to continue this line of inquiry.

6. Summary Group Size and Hierarchy – Underway Alternative Forms Social Interaction – Future Migration and Assimilation - Future