Kindred spirits - Influences of siblings' perspectives on theory of mind

Two experiments were conducted to examine the development of a theory of mi nd in 265 children aged 3 to 5 years from families of varied size. Even aft er verbal mental age was controlled, those who had a sibling aged 12 months to 12 years outperformed only-children in both experiments. However, the p resence of a very young infant, or of siblings who were teenagers or young adults, exerted no benefit. Also, in contrast to some previous studies, you nger child siblings and twins were just as helpful as older child siblings. The presence of multiple child siblings of varied ages above and below tha t of the participant predicted advanced theory of mind development over and above the effects of own age and verbal ability, despite the fact that nei ther overall family size nor birth order were significant predictors. These findings were reconciled with those of previous sibling constellation rese arch around a model of family social influences in which the opportunity to play, converse, and disagree in distinctively childish ways with brothers and sisters provides unique insights into the workings of the human mind. ( C) 2001 Elsevier Science Inc. All rights reserved.