A theory of developmental change in quantitative phenotypes applied to cognitive development
A model is presented for the changes in familial resemblance as a function of age. The model allows for separate developmental components of genetic and environmental effects and for the influence of earlier phenotypic values on current measurements. Genetic and environmental effects may be specific to occasions or constant over time. Expected covariances are derived within individuals and between relatives measured at different ages. Parameter substitution shows that models with different assumptions about the mechanism of development yield different predictions for temporal changes in family resemblance. The application of the model is illustrated by the analysis of published longitudinal data on cognitive development. The data suggest that the continuity of cognitive performance over time and the increase in heritability with age reflect the cumulative long-term effects of a single set of genes expressed throughout development. The quality of the shared environment changes from family to family over time but appears to exercise a long-term effect on cognitive development.
Key Wordsdevelopment aging path analysis heritability family resemblance quantitative inheritance cognition twins
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- Carey, G. (1985). Sibling imitation and contrast effects.Behav. Genet. (in press).Google Scholar
- Corey, L. A., Eaves, L. J., Mellen, B. G., and Nance, W. E. (1986). Testing for developmental changes in gene expression on resemblance for quantitative traits in kinships of monozygotic twins.Genetic Epidemiol. (Submitted).Google Scholar
- Eaves, L. J. (1978). Twins as a basis for the causal analysis of personality. In Nance, W. E. (ed.),Twin Research: Psychology and Methodology, Alan R. Liss, New York, pp. 151–174.Google Scholar
- Fischbein, S. (1981). Heredity-environment influences on growth and development during adolescence. In Gedda, L. L., Parisi, P., and Nance, W. E. (eds.),Twin Research III. Intelligence, Personality and Development, Alan R. Liss, New York, pp. 211–226.Google Scholar
- Hay, D. A., and O'Brien, P. (1981). The interaction of family attitudes and cognitive abilities in the La Trobe Twin Study of behavioral and biological development. In Gedda, L. L., Parisi, P., and Nance, W. E. (eds.),Twin Research III. Intelligence, Personality and Development, Alan R. Liss, New York, pp. 235–250.Google Scholar
- Plomin, R., and DeFries, J. C. (1985).Origins of Individual Differences in Infancy: The Colorado Adoption Project, Academic Press, Orlando, Fla.Google Scholar
- Rao, D. C., Morton, N. E., and Yee, S. (1976). Resolution of cultural and biological inheritance by path analysis.Am. J. Hum. Genet. 26:331–359.Google Scholar
- Young, P. A., Eaves, L. J., and Eysenck, H. J. (1980). Intergenerational stability and change in the causes of variation in personality.Person. Indiv. Diff. 1:35–55.Google Scholar