title: Parent ratings of EAS temperaments in twins, full siblings, half siblings, and step siblings.
abstract: A twin/family design was used to explore genetic contributions to personality; to evaluate whether twins and nontwins yield different genetic results; and to test for the presence of contrast effects, the tendency of a rater to contrast one sibling with the other, thereby magnifying existing behavioral differences. The sample consisted of 708 adolescent same-sex sibling pairs from 10 to 18 years of age. Pairs included identical (monozygotic; MZ) and fraternal (dizygotic; DZ) twins, and full siblings in nondivorced families; and full, half, and unrelated siblings in stepfamilies. Mothers and fathers rated the temperament of their children on the EAS Temperament Survey (A. H. Buss & R. Plomin, 1984). Model-fitting analyses revealed significant genetic influences on each of the four EAS dimensions; however, for some dimensions, heritability estimates were significantly greater for twins than for nontwins. Overall, the data were best described by a sibling interaction model, which indicated significant contrast effects.
authors.affiliation: Center for Developmental and Health Genetics, Pennsylvania State University, University Park 16802, USA.
authors.forename: K J
authors.initials: KJ
authors.lastname: Saudino
authors.forename: S
authors.initials: S
authors.lastname: McGuire
authors.forename: D
authors.initials: D
authors.lastname: Reiss
authors.forename: E M
authors.initials: EM
authors.lastname: Hetherington
authors.forename: R
authors.initials: R
authors.lastname: Plomin
mesh_terms: D000293:Adolescent; D002648:Child; D005260:Female; D006801:Humans; D008297:Male; D008957:Models, Genetic; D010551:Personality / Q000235:genetics; D010552:Personality Assessment; D012801:Sibling Relations; D012931:Social Environment; D013694:Temperament; D014427:Twins / Q000235:genetics* / Q000523:psychology; D014429:Twins, Dizygotic / Q000235:genetics / Q000523:psychology; D014430:Twins, Monozygotic / Q000235:genetics / Q000523:psychology