Developing Intuitions that Close Friends Know the Content of Each Other’s Minds

To maintain and develop close relationships, people need to accurately represent the minds of close others. Although studies have characterized the development of children’s theory of mind and children’s theory of relationships, it is largely unknown whether and how children think about mental state reasoning within close relationships. In three experiments, we asked whether children think of accurate mental state reasoning as a cue to social closeness. In Experiment 1 (n = 145), we found that 4- to 9-year-old children inferred that characters who are socially close know about each other’s goals and desires. In Experiment 2 (n = 137), we found that 6- to 9-year-old children, but not younger children, inferred that characters who are correct about each other’s minds are socially close. Children did not make the same inferences, however, concerning knowledge about external states of the world. In Experiment 3 (n = 79), we conceptually replicated the main findings from Experiments 1 and 2, and we found that 6- to 9-year-old children did not form the same inferences concerning knowledge about observable features of individuals (e.g., an individual’s outfit); children’s inferences were specific to unobservable mental content. Thus, by 6 years of age, children apply their theory of mind and their theory of relationships to make sense of whether and how people are connected to each other, as well as the strength and nature of those connections.