How do people react to setbacks and successes? I introduce a new measure of challenge-seeking to determine the effect of winning and losing in a competition on the willingness to seek further challenges. Participants in a lab experiment compete in two-person tournaments and are then informed of...

I study how gender differences in willingness to compete evolve over time in response to experience. Participants in a lab experiment perform the same real-effort task over several rounds. In each round, they have to choose between piece-rate remuneration and a winner-takes-all competition. At...

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...

I analyze Dutch panel data that contains rich information on voting, political opinions, and personality traits. I show that "adversarial" preferences - competitiveness, negative reciprocity, distrust, and selfishness - are strong predictors of right-wing and populist political preferences....

I analyze Dutch panel data that contains rich information on voting, political opinions, and personality traits. I show that "adversarial" preferences - competitiveness, negative reciprocity, distrust, and selfishness - are strong predictors of right-wing and populist political preferences....