A foundational mechanism underlying human cooperation is reciprocity. In the context of repeated interactions with others, it is not always clear the degree to which in-kind responses reflect responsiveness to partners' prior behaviors ("reactive" responses), an interest unrelated to the partner ("nonreactive" responses), or…

People frequently need to cooperate despite having strong self-serving motives. In the current study, pairs of 5- and 7-year-olds (N = 160) faced a one-shot coordination problem: To benefit, children had to choose the same of 3 reward divisions. They could not communicate or see each other and thus had to accurately predict each other's choices to…

The problem with collaboration is that there are temptations to defect. Explicit joint commitments are designed to mitigate some of the risks, but people also feel committed to others implicitly when they both know together that they each hold the other's fate in their hands. In the current study, pairs of 3-year-old and 5-year-old children (N =…

Ownership is a cornerstone of many human societies and can be understood as a cooperative arrangement, where individuals refrain from taking each other's property. Owners can thus trust others to respect their property even in their absence. We investigated this principle in 5- to 7-year-olds (N = 152) from 4 diverse societies. Children…

Human cooperative communication involves both an informative intention that the recipient understands the content of the signal and also a (Gricean) communicative intention that the recipient recognizes that the speaker has an informative intention. The degree to which children understand this 2-layered nature of communication is the subject of…

This study investigated the development of sharing expectations and sharing behavior in 3 groups of 3-, 4-, and 5-year-old children. We examined (a) whether preschool children expect a person to share more with a friend than with a disliked peer and (b) whether their expectation about others' sharing behavior depends on whether there is a cost or…

It has been argued that children who possess an advanced theory of mind (ToM) are more likely to act prosocially, yet the empirical findings are mixed. To address this issue definitively, a meta-analytic integration of all prior literature that met appropriate inclusion criteria was conducted. In total, 76 studies including 6,432 children between…