• Reading ability;
  • environmental influences;
  • twins;
  • common environment effects

Abstract The influences of social and family characteristics on individual differences in reading and spelling ability and IQ were investigated for 550 twin children aged 13 yrs. Measures of family social circumstances, parental background, the emotional atmosphere at home and the family's reading behaviour were used as predictor variables in multiple regression analyses with reading, spelling and IQ as dependent variables. There were consistent relationships between many of these measures and the dependent variables. The findings are compared to a previous biometrical genetic analysis of the same data set. It is concluded that the results are within the limits predicted by the genetic analysis. Most of the effect of these environmental influences on children are general, i.e. related to IQ, and not specifically related to reading. After controlling for the effects of IQ on reading, only family size and some aspects of parent-child relationships were significant predictors of reading ability