John C. DeFries – författare

Some of the most intriguing issues in the study of cognitive, social, emotional, and physical development arise in the debate over nature versus nurture; a debate difficult to resolve because it is difficult to separate the respective contributions of genes and environment to development.The most powerful approach to this separation is through longitudinal adoption studies. The Colorado Adoption Project (CAP) is the only longitudinal adoption study in existence examining development continuously from birth to adolescence, which makes it a unique, powerful, and tremendously valuable resource. CAP is an ongoing assessment of 245 adopted children and 245 biological control children assessed from birth to early adolescence.This book is the fourth in a series describing CAP results. This latest volume, edited by four eminent researchers in developmental psychology, builds on the large body of research already generated by investigating the role of genes and environments on early adolescent development.

Quantitative genetics offers a general theory of the development of individual differences that suggests novel concepts and research strategies: the idea that genetic influences operate in age-to-age change as well as in continuity for example. Quantitative genetics also provides powerful methods to address questions of change and continuity, including model-fitting approaches that test the fit between a specific model of genetic and environmental influences and observed correlations among family members, which are here helpfully introduced. A simple parent and offspring model is extended to include longitudinal and multivariate analyses. Longitudinal quantitative genetic research is essential to the understanding of developmental change and continuity. The largest and longest longitudinal adoption study is the Colorado Adoption Project, which has generated much of the rich data on the progress from infancy to early childhood on which the authors draw throughout this 1988 book. Their conclusions about what we know, and what we need to learn, about the origins of individual differences will interest a wide range of readers.