Interpersonal utility and children's social inferences from shared preferences.

Similarity of behaviors or attributes is often used to infer social affiliation and prosociality. Does this reflect reasoning using a simple expectation of homophily, or more complex reasoning about shared utility? We addressed this question by examining the inferences children make from similar choices when this similarity does or does not cause competition over a zero-sum resource. Four- to six-year-olds (N = 204) saw two vignettes, each featuring three characters (a target plus two others) choosing between two types of resources. In all stories, each character expressed a preference: one 'other' chose the same resource as the target, while a second 'other' chose the different resource. In one condition there were enough resources for all the characters; in the other condition, one type of resource was limited, with only one available (inducing potential competition between the target and the similar-choice other). Children then judged which of the two 'other' characters was being nicer (prosocial judgment) and which of the two was more preferred by the target (affiliative inference). When resources were limited (vs. unlimited), children were less likely to select the similar other as being nice. Children's initial tendency to report that the target preferred the similar other was also eliminated in the limited resource scenario. These findings show that children's reasoning about similarity is not wholly based on homophily. Instead, by reasoning about shared utility - how each person values the goals of others - children engage in flexible inferences regarding whether others' similar preferences and behaviors have positive or negative social meaning.