The Strange Case of c² = 0: What Does It Imply for Views of Human Development?

Abstract

A large body of evidence from behavior genetic designs (twins, adoptions, etc.) leads to a somewhat surprising conclusion: For many important behavioral traits in adulthood, c ², the effect on siblings of having shared a family environment as children, is close to zero. The value of c ² assessed early in life while the siblings are still sharing the family environment is, however, appreciable. Such findings raise the question of whether factors such as the imitation of parents or sharing childhood peers have lasting effects on personality and abilities. I discuss some exceptions to the generalization c ² = 0, and I offer advice on research strategies to clarify matters further.

Notes

Plaisance, K. S. (2006). Behavioral genetics and the environment: The generation and exportation of scientific claims. Unpublished doctoral dissertation, University of Minnesota, Minneapolis.