The Environments of Adopted and Non-adopted Youth: Evidence on Range Restriction From the Sibling Interaction and Behavior Study (SIBS)

Abstract

Previous reviews of the literature have suggested that shared environmental effects may be underestimated in adoption studies because adopted individuals are exposed to a restricted range of family environments. A sample of 409 adoptive and 208 non-adoptive families from the Sibling Interaction and Behavior Study (SIBS) was used to identify the environmental dimensions on which adoptive families show greatest restriction and to determine the effect of this restriction on estimates of the adoptive sibling correlation. Relative to non-adoptive families, adoptive families experienced a 41% reduction of variance in parent disinhibitory psychopathology and an 18% reduction of variance in socioeconomic status (SES). There was limited evidence for range restriction in exposure to bad peer models, parent depression, or family climate. However, restriction in range in parent disinhibitory psychopathology and family SES had no effect on adoptive-sibling correlations for delinquency, drug use, and IQ. These data support the use of adoption studies to obtain direct estimates of the importance of shared environmental effects on psychological development.

Perceived relationship quality in adolescents following early social-emotional deprivation

“…Among noninstitutionalized domestic adoptees, no difference was found in relationship quality between adoptees and their non-adopted siblings and two biological non-adopted siblings (McGue et al, 2007). Behaviorally, PI children adopted as sibling groups have higher ages at adoption but have lower or similar rates of behavior problems compared to single adoptees (Boer, Versluis-den Bieman, & Verhulst, 1994;Van den Oord, Boomsma, & Verhulst, 1994), and similar patterns are found for domestic adoptees (Erich & Leung, 2002;Hegar, 2005).…”

The Heritability of Life Events: An Adolescent Twin and Adoption Study

“…For the nonadoptive families, we required that the siblings be full, biological siblings. More detailed information on assessments, inclusion criteria, as well as comparisons of participating to nonparticipating contacted families can be found in Iacono and McGue (2002) for the twins and McGue et al (2007) for the sibling pairs.…”

The Early Growth and Development Study: Using the Prospective Adoption Design to Examine Genotype–Environment Interplay

“…Although the demographic characteristics of the adoptive parents were more favorable than those of the birth parents (as in prior adoption studies; DeFries, Plomin, & Fulker, 1994), a systematic test of range restriction biases has shown negligible effects on estimates of heritability and the environment, even when range restriction was present (McGue et al, 2007). Further, the differences between birth family and adoptive family characteristics suggest the unique utility of adoption as a preventive intervention focused on children's sociodemographic environments.…”