Nancy Segal: California State University, Fullerton

An overview of the origins, methods, findings, implications and controversies from the Minnesota Study of Twins Reared Apart is provided. This study, which took place between 1979 and 1999 at the University of Minnesota, accumulated a wealth of behavioral, physical and medical data on 137 reared apart twin pairs, 81 monozygotic (MZA) and 56 dizygotic (DZA). The focus will be on the personality and twin relationship findings, and their comparison with comparable data from an ongoing study of personality similarity and social relatedness between unrelated individuals who look alike, but are genetically unrelated (U-LAs). The U-LAs allow unique assessment of issues and questions relevant to behavioral genetic and evolutionary-based analyses. It is concluded that (1) similar treatment of MZ twins results from their shared behavioral traits, rather than their matched appearance as some critics have claimed, and (2) physical resemblance does not predict close social relations between people in the absence of perceived behavioral similarities.