Theory of Mind Is Contagious: You Catch It from Your Sibs

This is the authors' abstract. We don't add key points for this paper.

This study investigated the relation between family size and ''theory of mind.'' Results from an experiment with 3- and 4-year-olds showed that children from larger families were better able than children from smaller families to predict a story character's mistaken (false-belief based) action. Results from a second experiment on children with exactly 1 sibling failed to show any superiority of older over younger siblings in promoting earlier understanding of belief. The data are interpreted as suggesting that sibling interaction provides a rich ''data base'' for building a theory of mind, and this is discussed in relation to other studies showing that particular kinds of interaction between sibling and child, or caregiver and child, have a beneficial effect on the understanding of false belief.