The Prosocial Functions of Gratitude in Early Development

Gratitude is argued to motivate prosocial behavior and thereby help uphold cooperation in large groups. Among adults, feelings of gratitude motivate both direct reciprocity (repaying one’s benefactor) and upstream reciprocity (acting prosocially towards new individuals), and recipients’ displays of gratitude elicit affiliation and cooperation from observers. The present set of studies examined the ontogeny of these prosocial functions of gratitude. We found that among children in Germany and the US, a gratitude-like mechanism motivated direct reciprocity as early as age 3 years. Moreover, 4-year-olds (but not 3-year-olds) showed evidence of upstream reciprocity and this too seemed to be motivated by a gratitude-like mechanism. By 4 to 5 years, children also showed greater affiliation and cooperation towards grateful than non-grateful recipients. Thus, a nascent sense of gratitude may motivate even young children to behave prosocially and thus to uphold cooperation.