GENETIC AND ENVIRONMENTAL SOURCES OF CONSISTENCY AND VARIABILITY IN POSITIVE AND NEGATIVE MOOD

Several studies have found a genetic influence on person x situation i nteractions of behaviours and emotions. For five situations we assesse d current positive and negative mood for a sample of 168 monozygotic a nd 132 dizygotic adult twin pairs completing self-report rating scales . We used structural equation model fitting to estimate genetic and en vironmental influences on the stability and variability of moods acros s situations. Our results indicate that genetic as well as shared and nonshared environmental influences contribute to the consistency of mo ods. Contrary to previous findings, the variability of positive and ne gative mood is mainly attributed to nonshared environmental influences and only marginally attributed to genetic or shared environmental eff ects. (C) 1998 John Wiley & Sons, Ltd.