title: Theory of mind may be contagious, but you don't catch it from your twin.
abstract: The theory-of-mind abilities of twins, children with nontwin siblings, and only children were compared to investigate further the link between number and type of siblings and theory-of-mind abilities. Three- to 5-year-old children with nontwin siblings outperformed both only children and twins with no other siblings, twins who also had other siblings outperformed twins who did not, and children with at least 1 opposite-sex sibling outperformed children with only same-sex siblings. Twins performed significantly better when asked about the false beliefs of their twins than they did when asked about the false beliefs of their friends. Results are discussed in terms of potential mechanisms that may account for the twin and sibling effects.
authors.affiliation: Department of Psychology, Bryn Mawr College, PA 19010, USA. kcassidy@brynmawr.edu
authors.forename: Kimberly
authors.initials: K
authors.lastname: Wright Cassidy
authors.forename: Deborah
authors.initials: D
authors.lastname: Shaw Fineberg
authors.forename: Kimberly
authors.initials: K
authors.lastname: Brown
authors.forename: Alexis
authors.initials: A
authors.lastname: Perkins
mesh_terms: D002675:Child, Preschool; D003071:Cognition; D003469:Culture; D005260:Female; D006801:Humans; D008297:Male; D011581:Psychological Tests; D011582:Psychological Theory; D014427:Twins / Q000502:physiology*