Despite decades of research on heuristics and biases, evidence on the effect of large incentives on cognitive biases is scant. We test the effect of incentives on four widely documented biases: base-rate neglect, anchoring, failure of contingent thinking, and intuitive reasoning. In laboratory experiments with 1,236 college students in Nairobi, we implement three incentive levels: no incentives, standard lab payments, and very high incentives. We find that very high stakes increase response times by 40% but improve performance only very mildly or not at all. In none of the tasks do very high stakes come close to debiasing participants.

Recent literature presents evidence that men are more competitively inclined than women. Since top-level careers usually require competitiveness, competitiveness differences provide an explanation for gender gaps in wages and differences in occupational choice. A natural question is whether women are born less competitive or whether they become so through the process of socialization. To pinpoint when in the socialization process the difference arises, we compare the competitiveness of children in matrilineal and patriarchal societies. We find that while there is no difference at any age in the matrilineal society, girls become less competitive around puberty in the patriarchal society.