Personality formation in the Kibbutz

Longitudinal study of interpersonal dependency in female twins

BACKGROUND

Interpersonal dependence is thought to be important in a number of physical and psychological disorders. There are several developmental theories that suggest environmental influences in childhood are important.

METHOD

A twin study methodology was used to look at the genetic and environmental influences on interpersonal dependence as measured by a sub-scale of the Interpersonal Dependency Inventory with a population-based sample of 2230 twins.

RESULTS

Psychometric analysis revealed that this was a stable measure and that there was a substantial degree of construct validity. Both univariate and longitudinal twin analysis suggested that there was a modest genetic influence and a large, specific environment influence on interpersonal dependency as measured by this scale. The longitudinal analysis revealed that the genetic influence was stable over the time-scale sampled and the environmental influence was moderately stable.

CONCLUSIONS

This finding is at odds with theories that suggest shared environment is important in the aetiology of interpersonal dependency.

POSSESSION IN HUMANS: AN EXPLORATORY STUDY OF ITS MEANING AND MOTIVATION

This study examined the nature of possession and ownership in a developmental and cross-cultural context. It was an exploratory study attempting to map out the various dimensions of the meaning of possession, and the motivation for possessive behaviour. An open-ended interview was administered to (a) 150 American subjects, 30 at each of five age levels (kindergarten, second, fifth, and eleventh grades, and 40- to 50-year-old adults), and (b) 120 Israeli subjects, 60 from the kibbutz and 60 from the city (in each case, 30 of kindergarten age and 30 of fifth-grade age). A content analysis was performed on the interview responses. The resulting dimensions of the meaning of possession and of the motivation for possession are presented, and the relative saliencies of these dimensions for the different age and cultural groups are discussed. Of particular importance to all ages and cultural groups were the two dimensions of (a) effectance and control of possessions, and (b) positive affect for possessions. A large number of other dimensions were also obtained, often differing in their relative importance at different ages. It is hoped that the results will lay the foundations for subsequent empirical work on this topic.