Environmental Mediation and The Twin Design Article Received: 07 July 2004 Accepted: 23 November 2004 DOI:
Cite this article as: Purcell, S. & Koenen, K. Behav Genet (2005) 35: 491. doi:10.1007/s10519-004-1484-9 Abstract
Behavior genetic twin designs are increasingly used to study the effects of a measured environment whilst controlling for genetic variation. In this research note, we show that, in the context of the classical twin design, (1) when the environmental variable is necessarily shared between twins, the notion of controlling for genetic influence is logically flawed and (2) when the environmental variable varies between twins in the same family, partial control for genetic influence is possible, but only if appropriate analytic models are used, which is commonly not the case. Based on a simple simulation study, recommendations are given as to which methods should be applied and which should be avoided.
Keywords Environmental mediation maximum likelihood regression simulation twins variance components References Caspi, A., Taylor, A., Moffitt, T., Plomin, R. 2000 Neighborhood deprivation affects children’s mental health: environmental risks identified in a genetic design Psychol. Sci. 11 338 342 PubMed Google Scholar DeFries, J., Fulker, D. 1985 Multiple regression analysis of twin data Behav. Genet. 15 467 473 PubMed Google Scholar DeFries, J., Fulker, D. 1988 Multiple regression analysis of twin data: etiology of deviant scores versus individual differences Acta Genet. Med. Gemel. 37 205 216 Google Scholar DiLalla, L., Gottesman, I. 1991 Biological and genetic contributors to violence--Widom’s untold tale Psychol. Bull. 109 125 129 PubMed Google Scholar D’Onofrio, B., Turkheimer, E., Eaves, L., Corey, L., Berg, K., Solaas, M., Emery, R. 2003 The role of the children of twins design in elucidating causal relations between parent characteristics and child outcomes J. Child Psychol. Psychiatry 44 1130 44 PubMed Google Scholar Jaffee, S. R., Caspi, A., Moffitt, T. E., Taylor, A. 2004 Physical maltreatment victim to antisocial child: Evidence of an environmentally mediated process J. Abnorm. Psychol. 113 44 55 PubMed Google Scholar Kendler, K., Neale, M., Prescott, C., Kessler, R., Heath, A., Corey, L., Eaves, L. 1996 Childhood parental loss and alcoholism in women: a causal analysis using a twin-family design Psychol. Med. 26 79 95 PubMed Google Scholar Koenen, K., Moffitt, T., Caspi, A., Taylor, A., Purcell, S. 2003 Domestic violence is associated with environmental suppression of iq in young children Dev. Psychopathol. 15 297 311 PubMed Google Scholar Miller, P., Mulvery, C., Martin, N. 2001 Genetic and environmental contributions to educational attainment in Australia Econ. Educ. Rev. 20 211 224 Google Scholar
Neale, M. (1997). Mx: Statistical modeling. Box 980126 VCU, Richmond VA 23298.
Plomin, R., Bergeman, C. S. 1991 The nature of nurture: genetic influence on environmental measures Behav. Brain Sci. 14 373 386 Google Scholar Rodgers, J. L., Rowe, D. C., Chengchang, L. 1994 Beyond nature versus nurture: DF analysis of nonshared influences on problem behaviors Dev. Psychol. 30 374 384 Google Scholar Turkheimer, E., D’Onofrio, B., Maes, H., Eaves, L., Waldron, M. 2000 Nonshared environment: a theoretical, methodological and quantitative review Psychol. Bull. 126 78 108 PubMed Google Scholar Widom, C. 1989 Does violence beget violence? A critical examination of the literature Psychol. Bull. 106 3 28 PubMed Google Scholar Copyright information
© Springer Science+Business Media, Inc. 2005