It is now generally accepted that some people are more altruistic, more trusting, or more reciprocal than others, but it is still unclear whether these differences are innate or a consequence of nurture. We analyse the correlation between handedness and social preferences in the lab and find...

We examine whether social preferences are determined by hormones. We do this by investigating whether markers for the strength of prenatal testosterone exposure (finger length ratios) and current exposure to progesterone and oxytocin (the menstrual cycle) are correlated with choices in social...

"Recent research documents that while men are eager to compete, women often shy away from competitive environments. A consequence is that few women enter and win competitions. Using experimental methods we examine how affirmative action affects competitive entry. We find that when women are...