MateFriendChoiceTwins05
Research Article MateChoiceandFriendshipin Twins EvidenceforGeneticSimilarity J. Philippe Rushton and Trudy Ann Bons The University of Western Ontario, London, Ontario, Canada ABSTRACT—This study examined the genetic and environ- mental contribution to people’s preference for spouses and friends to be similar to themselves. In their responses to 130 personality, attitude, and demographic questions, 174 pairs of monozygotic (MZ) twins resembled each other (r5 .53) more than did 148 pairs of dizygotic (DZ) twins (r5 .32), 322 pairs of spouses (r5.32), and 563 pairs of best friends (r5.20). It was not previously recognized that spouses and friends are as similar as DZ twins. MZ twins also chose spouses and best friends more similar to their co- twins’ friends and spouses than did DZ twins (meanrs5.22 vs. .14). The twins’ preference for spouses and friends similar to themselves was about 34% due to the twins’ genes, 12% due to the twins’ common environment, and 54% due to the twins’ unique (nonshared) environment. Similar- ity to partners was more pronounced on the more heritable items than the less heritable items. It is concluded that peo- ple are genetically inclined to choose as social partners those who resemble themselves at a genetic level. As the English language makes obvious, ‘‘likeness goes with liking.’’ Similarity, whether actual or perceived, is one of the most important variables in all of social psychology, influencing in- terpersonal processes from attraction to grouping and from per- suasion to prejudice. People’s preference for their social partners to be similar to themselves is usually attributed to cultural and cognitive factors, such as being raised in a particular way or confirming one’s judgments about the world. Evolutionary factors may also be at work through genes and sexual imprinting (Be- reczkei, Gyuris, & Weisfeld, 2004; Rushton, 1989a). In a study of 1,000 sexually interacting couples of northern European appearance (judged by photographs)…