Fairness, prosociality, hypocrisy, and happiness: Children's and adolescents' motives for showing unselfish behaviour and positive emotions.

The present study examined what motives account for age-related decreases in selfish behaviour and whether these motives equally predict positive emotions when making a moral decision. The study was based on a sample of 190 children and adolescents (101 females) from three different age groups (childhood, early adolescence, and middle adolescence, M = 12.9 years, SD = 2.58). A decision-making task was used where participants chose between (1) maximizing their own self-interest versus (2) being prosocial, (3) being fair, or (4) appearing fair while avoiding the costs of actually being fair. Overall, prosociality and fairness were equally important motives for unselfish behaviour. At the same time, the importance of fairness motivation increased with age. Hypocrisy motivation was less frequent than expected by chance. Prosociality was most strongly and positively associated with self-rated happiness about the decision, whereas the opposite was found for individuals who were motivated by fairness. Overall, the study indicates that children's or adolescents' unselfish behaviour in decision-making tasks are driven by a variety of motives with diverse emotional implications. The relative importance of these motives changes over the course of development. STATEMENT OF CONTRIBUTION: What is already known on this subject? Older children behave less selfishly in resource allocation tasks. Prosocial behaviour is associated with positive emotions. What the present study adds? Unselfish behaviour is equally motivated by fairness and prosociality. Fairness motivation increases from childhood throughout adolescence. Decisions motivated by prosociality are experienced as more positive than decisions motivated by fairness.