Sex differences in motivational biases over instrumental actions.

Motivational (i.e., appetitive or aversive) cues can bias value-based decisions by affecting either direction and intensity of instrumental actions. Despite several findings describing important interindividual differences in these biases, whether biological sex can also play a role is still up to debate. By comparing females and males in both appetitive and aversive Pavlovian-to-Instrumental Transfer paradigms we found that, while motivational cues similarly bias the direction of instrumental actions in both sexes, the intensity of such actions is increased by the cue in male participants only. The present results constitute compelling evidence that a crucial motivational bias of daily actions directed to obtaining rewards or avoiding punishments is modulated by biological sex. This evidence sheds new light on the role of sex in motivational processes that underlie decision-making, highlighting the importance of considering sex as a crucial factor in future research on this topic.