Behavior genetics research on personality: Moving beyond traits to examine characteristic adaptations

Broad and narrow environmental and genetic sources of personality differences: An extended twin family study

OBJECTIVE

Several personality theories distinguish between rather genetically rooted, universal dispositional traits (DTs) and rather environmentally shaped, more contextualized characteristic adaptations (CAs). However, no study so far has compared different measures of theoretically postulated DTs and CAs regarding their environmental and genetic components while considering differences in measurement abstraction and reliability. This study aims to bridge this gap by testing the assumed differences in the sensitivity to environmental influences based on representative sets of DTs (Big Five and HEXACO domains and facets) and CAs (goals, interests, value priorities, religiousness, and self-schemas).

METHOD

Using intra-class correlations and running extended twin family and spouses-of-twins model analyses, we analyzed a large data set (N = 1967) encompassing 636 twin pairs, 787 parent-offspring dyads, and 325 spouses/partners.

RESULTS

Findings consistently support lower environmentality of DTs compared to CAs. On average, more than half of reliable variance in DTs was genetic, whereas the reverse was found for CAs. Larger environmental components in CAs were primarily attributable to larger individual-specific effects (beyond error of measurement) and factors shared by spouses.

CONCLUSIONS

Findings are discussed against the background of the definitional distinction between DTs and CAs and the value of extended twin family data.

Building causal knowledge in behavior genetics without racial/ethnic diversity will result in weak causal knowledge

Behavior genetics often emphasizes methods over the underlying quality of the psychological information to which the methods are applied. A core aspect of this quality is the demographic diversity of the samples. Building causal genetic models based only on European-ancestry samples compromises their generalizability. Behavior genetics researchers must spend additional time and resources diversifying their samples before emphasizing causation.

A cultural evolutionary behavior genetics will need a more sophisticated conceptualization of cultural traits

A framework that brings together cultural perspectives and behavior genetics has long been needed. To be successful, however, we need sophistication in the conceptualization of culture. Here, we highlight three imperatives to this end: the need for a clear definition of cultural traits, inclusion of the role of societal power, and recognizing the distinction between traits and characteristic adaptations.