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 their social partners. Although studies have characterized many aspects of children’s intuitive theory of the mind and children’s intuitive theory of relationships, it is largely unknown whether and how children think about mental state reasoning within relationships. In three experiments, we asked whether children think accurate mental state reasoning is 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 think that being correct about external states of the world was evidence that a character was close to another. 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 integrate their intuitive theories of the mind and relationships to make sense of whether and how people are connected to each other, as well as the strength and nature of those connections.