Genetic and Environmental Influences in Adolescent Peer Socialization: Evidence from Two Genetically Sensitive Designs

Abstract

Harris argues that peer relationships are the chief determinants of personality development. Harris's thesis makes the behavioral genetic investigation of peer groups particularly timely. The present study examined genetic and environmental contribution to self-reported peer-group characteristics in two samples of adolescent siblings: 180 adoptive and nonadoptive sibling pairs from the Colorado Adoption Project, and 386 sibling pairs from the Nonshared Environment and Adolescent Development Study. Substantial genetic influence emerged for college orientation, with the remaining variance accounted for by nonshared environment. For delinquency, however, the majority of the variance was explained by nonshared environment. Although genetic influence was implicated for peer popularity in twin analyses, genetic factors were not important in explaining individual differences in nontwin siblings. These results suggest that although some dimensions of peers are somewhat mediated by genetic factors, nonshared environmental influence is substantial.

A genetically informative developmental study of the relationship between conduct disorder and peer deviance in males

“…Other twin studies (Iervolino et al 2002;Walden et al 2004) and our own prior analyses in this sample suggest important shared environmental risks for PD. These influences most probably exist at multiple levels, two of which, neighborhood and family, are likely to be of particular importance.…”

Genetic and Environmental Influences on Levels of Self-Control and Delinquent Peer Affiliation

“…To illustrate, Iervolino et al (2002) analyzed data from the Nonshared Environment in Adolescent Development (NEAD) research and from the Colorado Adoption Project (CAP) to estimate the relative importance of genes and the environment on deviant peer affiliations.…”

Correlated genotypes in friendship networks

“…Although people apparently choose their friends freely, genes are known to play a role in the formation (1), attributes (2)(3)(4), and network structures (5) of these unions. It remains unclear, however, whether variation in specific genes might be relevant to the process of friend selection or, distinctly, whether the process of choosing friends might result in correlated genotypes between friends.…”