We examine the role of cognitive ability and personality traits in a gift exchange experiment. Controlling for cognitive ability and personality characteristics, men offer higher wages than women, and men and women with greater cognitive ability and greater agreeableness on the Big Five personality scale offer higher wages as well. Men provide greater effort than women do, and respond to higher wage rates with greater increases in effort. For both genders, one standard deviation increases in agreeableness and in wages generate similar increases in effort. Serious biases arise from omitting cognitive ability and pooling men and women.
