title: Examining the familial link between positive affect and empathy development in the second year.
abstract: Within a sample of 584 twins aged 12 to 25 months (292 pairs) studied longitudinally, positive affect measured through two laboratory pleasure episodes and maternal report at 12 and 22 months significantly predicted empathy-related helping and hypothesis testing assessed between 19 and 25 months. Girls showed significantly more concern than did boys, whereas boys engaged in hypothesis testing significantly more than did girls. Behavior-genetic analyses indicated substantial shared environmental influences for positive affect and empathy composites of helping and concern. Genetics and the nonshared environment influenced empathy-related hypothesis testing. The best fitting bivariate model included shared and nonshared environmental influences on positive affect and helping, with environment accounting for the covariation between the two traits. The covariation between positive affect and hypothesis testing was genetically influenced.
authors.affiliation: Department of Psychology, University of Wisconsin--Madison, 53706-1969, USA. mmvolbrecht@wisc.edu
authors.forename: Michele M
authors.initials: MM
authors.lastname: Volbrecht
authors.forename: Kathryn
authors.initials: K
authors.lastname: Lemery-Chalfant
authors.forename: Nazan
authors.initials: N
authors.lastname: Aksan
authors.forename: Carolyn
authors.initials: C
authors.lastname: Zahn-Waxler
authors.forename: H Hill
authors.initials: HH
authors.lastname: Goldsmith
mesh_terms: D000339:Affect; D002675:Child, Preschool; D004645:Empathy; D005260:Female; D020022:Genetic Predisposition to Disease / Q000235:genetics; D006379:Helping Behavior; D006801:Humans; D007206:Individuality; D007223:Infant; D008297:Male; D035863:Moral Development; D012737:Sex Factors; D012931:Social Environment; D013694:Temperament; D014427:Twins / Q000235:genetics* / Q000523:psychology