Are economists rational, or just different?

There is evidence that American economics undergraduates an more likely tha n others to act self-interestedly and less likely to behave cooperatively. In two experiments, differences between Americans and Canadians and between economics students and psychology students were examined. Data from simple bargaining and a prisoner's dilemma game are presented, which suggest that Canadian students may be more co-operative than American students, and psy chology students less selfish than either economics students or students; f rom other disciplines. However, these results suggest also that these relat ionships are not simple, and that other variables - such as gender - need t o be taken into account.