Knowing when to trust is an essential skill, but little is known about its cognitive development. No previous studies have examined the development of trust while controlling for age differences in altruism. We hypothesized that older children are more likely to trust, and that this age-related increase is not due to an increase in altruism. In two experiments, we compared the choices of kindergarten (4–5 years) and elementary school (9–10 years) children in economic games. Age was positively related to both trust and altruism, but more strongly to the former. The age difference in trust was robust when we controlled for partner age and the ability to delay gratification. We further hypothesized that older children are more attuned to the probability of reciprocity. Indeed, older children were more sensitive to changes in the game’s structure and the trustee’s characteristics, suggesting that they are not only more trusting, but more discerning in their decisions of when to trust.

DSA Proof. - Universe: The data was collected from kindergarten an elementary school children in Austria.