Sources of Variance in Personality Facets: A Multiple-Rater Twin Study of Self-Peer, Peer-Peer, and Self-Self (Dis)Agreement


  • This research was supported by a grant from Deutsche Forschungsgemeinschaft (Grant FOR 481/1-1).

concerning this article should be addressed to Christian Kandler, Department of Psychology, Bielefeld University, Universitätsstr. 25, D-33615 Bielefeld, Germany. E-mail:


ABSTRACT This study considered the validity of the personality structure based on the Five-Factor Model using both self- and peer reports on twins' NEO-PI-R facets. Separating common from specific genetic variance in self- and peer reports, this study examined genetic substance of different trait levels and rater-specific perspectives relating to personality judgments. Data of 919 twin pairs were analyzed using a multiple-rater twin model to disentangle genetic and environmental effects on domain-level trait, facet-specific trait, and rater-specific variance. About two thirds of both the domain-level trait variance and the facet-specific trait variance was attributable to genetic factors. This suggests that the more personality is measured accurately, the better these measures reflect the genetic structure. Specific variance in self- and peer reports also showed modest to substantial genetic influence. This may indicate not only genetically influenced self-rater biases but also substance components specific for self- and peer raters' perspectives on traits actually measured.