Genetic and shared environmental influences on leisure-time interests in male adolescents

The present study explored genetic and environmental influences on individual differences in adolescent leisure-time interests. One hundred and ninety identical and 100 fraternal male twin pairs, aged 17 and 18 years, all participants in the ongoing Minnesota Twin Family Study, completed 120 items of the Leisure-Time Interests (LTI) inventory. A principal components analysis with varimax rotation of the 120 items of the LTI yielded nine interpretable factors (Intellectual Activities, Sports, Music and Artistic Activities, Handicrafts, Hunting and Outdoor Activities, Foreign Travel, TV Viewing, Dating and Social Activities, and Religious Activities). Correlation and biometrical analyses indicated that: (1) both genetic and shared environmental factors contributed to individual differences in adolescent leisure-time interests, although the relative magnitude of the contribution of the two factors varied across different leisure-time interests, and (2) approximately half of the variance in adolescent leisure-time interests was associated with nonshared environmental influences. The results are discussed in the context of developmental changes in genetic and shared environmental influences on leisure-time interests.