Antisocial behaviours such as injuring opposing players are common in sport. This project aims to examine whether: frequency of antisocial sport behaviours is associated with players' emotional reactions to sport images; moral identity influences these emotional reactions; and moral identity moderates the effects of moral disengagement,which refers to psychological justifications of antisocial conduct, on athletes' emotional reactions. Adult team sport players who report high (N = 48) and low (N = 48) frequency of antisocial sport behaviours will be recruited. In one group of players, moral identity will be primed by getting them to write stories about moral traits. A control group will perform a writing task that will not prime their moral identity. Moral disengagement will be measured via a questionnaire. All players will view pleasant and unpleasant sport images on a computer screen. During image viewing, small electrical shocks will be delivered that will produce two physiological responses measured by the electrical activity of a muscle that closes the eyelid and the electrical activity of the brain. Players will also rate the images for unpleasantness. The two physiological responses and the image ratings will be used as measures of emotional reactions.