Is there a Gender Difference in False Belief Development?

Fifty-nine 3-year-olds were tested 3 times over a period of 7 months in order to assess the contribution of theory of mind to language development and of language to theory-of-mind development (including the independent contributions of syntax and semantics). Language competence was assessed with a standardized measure of reception and production of syntax and semantics (the Test of Early Language Development). Theory of mind was assessed with false-belief tasks and appearance-reality tasks. Earlier language abilities predicted later theory-of-mind test performance (controlling for earlier theory of mind), but earlier theory of mind did not predict later language test performance (controlling for earlier language). These findings are consistent with the argument that language is fundamental to theory-of-mind development.

Developmental changes in children's understanding of mind and emotion and their mental-state talk in conversations with friends were examined in a longitudinal study of 50 children (M age at each time point = 3 years 11 months, 4 years 6 months, 5 years 0 months). Significant and related improvements over time were found for both theory-of-mind task performance and affective perspective taking. Associated with these cognitive developments were quantitative and qualitative changes in children's references to mental states in their conversations with friends. Individual differences in theory of mind, emotion understanding, and mental-state talk were strikingly stable over the 13-month period. Although there were no gender differences in children's task performances, girls showed more frequent and more developed mental-state talk than boys.

There is clear evidence that parents can and do influence children. There is equally clear evidence that children’s genetic makeup affects their own behavioral characteristics, and also influences the way they are treated by their parents. Twin and adoption studies provide a sound basis for estimating the strength of genetic effects, although heritability estimates for a given trait vary widely across samples, and no one estimate can be considered definitive. This chapter argues that knowing only the strength of genetic factors, however, is not a sufficient basis for estimating environmental ones and indeed, that attempts to do so can systematically underestimate parenting effects. Children’s genetic predispositions and their parents’ childrearing regimes are seen to be closely interwoven, and the ways in which they function jointly to affect children’s development are explored.