Romantic Relationship Satisfaction Moderates the Etiology of Adult Personality

Abstract

The heritability of major normative domains of personality is well-established, with approximately half the proportion of variance attributed to genetic differences. In the current study, we examine the possibility of gene × environment interaction (G×E) for adult personality using the environmental context of intimate romantic relationship functioning. Personality and relationship satisfaction are significantly correlated phenotypically, but to date no research has examined how the genetic and environmental components of variance for personality differ as a function of romantic relationship satisfaction. Given the importance of personality for myriad outcomes from work productivity to psychopathology, it is vital to identify variables present in adulthood that may affect the etiology of personality. In the current study, quantitative models of G×E were used to determine whether the genetic and environmental influences on personality differ as a function of relationship satisfaction. We drew from a sample of now-adult twins followed longitudinally from adolescence through age 29. All participants completed the Multidimensional Personality Questionnaire (MPQ) and an abbreviated version of the Dyadic Adjustment Scale. Biometric moderation was found for eight of the eleven MPQ scales examined: well-being, social potency, negative emotionality, alienation, aggression, constraint, traditionalism, and absorption. The pattern of findings differed, suggesting that the ways in which relationship quality moderates the etiology of personality may depend on the personality trait.

Keywords: Biometric moderation; G×E; Personality; Relationship satisfaction.

Figure 1

Bivariate biometric moderation model with relationship variable moderating genetic and environmental effects on the personality variable (model displayed for single member of a twin pair). A=latent factor representing additive genetic influences; C=latent factor representing shared environmental variance; E=latent factor representing nonshared environmental influences. a_C, c_C, and e_C represent common variance shared between the moderator and outcome variables, and a_U, c_U, and e_U signify residual variance in the outcome after accounting for the moderator. The β coefficients index the direction and magnitude of the moderation effect. The total phenotypic variance in personality can be calculated by squaring and summing all of the paths leading to it, P= (a_C+βa_MCM)² + (c_C+βc_MCM)²+ (e_C+βe_MCM)² + (a_U+βa_MUM)² + (c_u+βc_MUM)² + (e_u+βe_MUM)².

Figure 2

Plot of the moderation of personality scales by increasing relationship satisfaction. Values are estimates from the extended univariate moderation model. A=additive genetic; C=shared environment; E= nonshared environment. Values shown are standardized (i.e., proportion of total variance due to genetic or environmental variance).

Figure 2

Plot of the moderation of personality scales by increasing relationship satisfaction. Values are estimates from the extended univariate moderation model. A=additive genetic; C=shared environment; E= nonshared environment. Values shown are standardized (i.e., proportion of total variance due to genetic or environmental variance).