Twin Research

Articles

Comparing the biological and cultural inheritance of personality and social attitudes in the Virginia 30 000 study of twins and their relatives

Lindon Eavesa1 c1, Andrew Heatha2, Nicholas Martina3, Hermine Maesa4, Michael Nealea5, Kenneth Kendlera6, Katherine Kirka7 and Linda Coreya8

a1 Virginia Institute for Psychiatric and Behavioral Genetics, Virginia Commonwealth University, Richmond, Virginia.

a2 Department of Psychiatry, Washington University, St Louis, USA.

a3 Queensland Institute of Medical Research and Joint Genetics Program, University of Queensland, Brisbane, Australia.

a4 Virginia Institute for Psychiatric and Behavioral Genetics, Virginia Commonwealth University, Richmond, Virginia.

a5 Virginia Institute for Psychiatric and Behavioral Genetics, Virginia Commonwealth University, Richmond, Virginia.

a6 Virginia Institute for Psychiatric and Behavioral Genetics, Virginia Commonwealth University, Richmond, Virginia.

a7 Queensland Institute of Medical Research and Joint Genetics Program, University of Queensland, Brisbane, Australia.

a8 Virginia Institute for Psychiatric and Behavioral Genetics, Virginia Commonwealth University, Richmond, Virginia.

Abstract

Measures of four dimensions of personality (Psychoticism, Extraversion, Neuroticism, and Lie scores) and six aspects of social attitudes (to sex, taxation, militarism, politics, religion and a general conservatism scale) were obtained by mailed questionnaire from 29 691 US subjects including adult twins (n = 14 761) their parents (n = 2360), their spouses (n = 4391), siblings (n = 3184) and adult children (n = 4800). After correction for the average effects of age, sex and source of sample, familial correlations were computed for 80 distinct biological and social relationships. The data allow for the estimation of the additive and non-additive effects of genes, assortative mating, vertical cultural inheritance and other non-parental effects of the shared environment on differences in personality and social attitudes. The interaction of genetic and environmental effects with sex may also be analyzed. Model-fitting analyses show that personality and social attitude measures differ markedly in major features of family resemblance. Additive and dominant genetic effects contribute to differences in both personality and attitudes, but the effects of the family environment, including vertical cultural transmission from parent to child, are much more marked for social attitudes than for personality. There is substantial assortative mating for social attitudes and almost none for personality. The causes of family resemblance depend significantly on sex for almost every variable studied. These findings clarify and extend the more tentative findings derived from previous twin, family and adoption studies.

Key Words:

  • personality;
  • attitudes;
  • cultural transmission;
  • assortative mating;
  • twins;
  • behavior genetics;
  • heritability;
  • sex differences

Correspondence:

c1 Correspondence: Dr Lindon Eaves, Department of Human Genetics, PO Box 980003, Richmond, Virginia 23298-0003, USA.

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