ABSTRACT
This chapter summarizes briefly what they have already learned about familiar similarity of cognitive functioning in adults and about the similarity of perceptions of family environments across generations. The chapter provides estimates of the relative importance of familial factors, early shared family environment, early nonshared family environments, and current family environment as they affect adult cognitive performance. The chapter makes somewhat strong assumptions about the utility of perceptions as measures of family environment and further investigations with better estimates of early environment as reported by the adult parents are needed. It presents findings from a large-scale longitudinal study of adult intellectual functioning, the Seattle Longitudinal Study that may inform them on the relative contribution of familial similarity due to genetic influences of certain cognitive traits as contrasted to the extent to which current cognitive performance may be attributed to family influences that are shared with other family members.
