Subjective well-being is heritable and genetically correlated with dominance in chimpanzees (Pan troglodytes)

The hypothesis that subjective well-being (SWB) is heritable and genetically correlated with Dominance was tested using 128 zoo chimpanzees. Dominance was a chimpanzee-specific personality factor including items reflecting Extraversion and low Neuroticism. SWB was measured with a 4-item scale. The best behavior genetic model included additive genetic and nonshared environmental effects for SWB and Dominance, marginal matemal effects for SWB, a high genetic correlation, and a low nonshared environmental correlation. Results indicated that the shared variance between SWB and Dominance was a consequence of common genes and that the unique variance between SWB and Dominance was a consequence of the nonshared environment. These findings indicate that common genes may underlie the correlation between human personality factors and SWB.     

THE IMPORTANCE OF NONGENETIC INFLUENCES ON ROMANTIC LOVE STYLES: A Twin-Family Study

Research in several disciplines reveals large individual differences in orientations to romantic love, yet the origins of the differences have been unclear In this first behavior genetic study of romantic love, biometric model fitting reveals that in contrast to other personality and attitude domains, where genetic factors account for approximately 50% of the reliable variance and shared environment has little effect, individual differences in romantic love are due almost exclusively to environment Moreover, the common family environment plays a sizable role in determining love styles, a finding compatible with theories stressing the importance of family interactions in personality development     

Heritabilities of Common and Measure-Specific Components of the Big Five Personality Factors

Three different measures of the Big Five personality dimensions were developed from the battery of questionnaires used in the National Merit Twin Study: one from trait self-rating scales, one from personality inventory items, and one from an adjective check list. Behavior-genetic models were fit to what the three measures had in common, and to the variance distinctive to each. The results of the model fitting agreed with other recent studies in showing the Big Five dimensions to be substantially and about equally heritable, with little or no contribution of shared family environment. Heritabilities for males and females did not differ significantly. For Agreeableness and Conscientiousness, some effect of shared environment was found for measure-specific variance on the personality inventory, and for Extraversion and Neuroticism, models involving nonadditive genetic variance or twin contrast effects provided slightly better fits.     

Behavioral genetic methods

Traditional behavioral genetic methods involve the use primarily of family, twin, and adoption correlations to estimate the relative contributions of genetic and environmental influences in the etiology of individual differences. These methods and representative results for personality are described. However, newer methods are emphasized: structural models and model-fitting, multivariate analysis, genetic change and continuity in development, shared and non-shared components of environmental variance, and genetic components of "environmental" variation. Because most applications of these behavioral genetic methods to the study of personality involve self-report omnibus questionnaires, an important direction for future research in this area is to use these methods to explore new issues and new measures that have emerged from personality theory and research during the past decade.     

The genetics and evolution of the general factor of personality

Three studies tested the hypothesis that a general factor of personality (GFP) underlies diverse individual differences including altruism, the Big Five factors of Openness, Conscientiousness, Extraversion, Agreeableness, and Emotional Stability, and the EAS temperament traits of Emotional Stability, Activity, and Sociability. In Study 1, 214 university students completed 36 personality scales. In Study 2, 322 pairs of monozygotic (MZ) and dizygotic (DZ) twins completed 29 5-point rating scales plus questionnaires. In Study 3, 575 pairs of 2- to 9-year-old Korean twins were rated by their mothers on 25 temperament scales. Factor analyses revealed a hierarchical organization with GFP at the apex and the Big Five and/or EAS temperament scales intermediate. The twin data show GFP has an early age of onset with 50% of the variance attributable to non-additive (dominance) genetic influence and 50% to unique, non-shared environmental influence. We discuss a life history matrix encompassing brain size, maturational speed, and longevity, plus emotional intelligence and the personality disorders, and suggest natural selection acted directionally to endow people with more cooperative and less contentious personalities than their archaic ancestors, or nearest living relatives, the chimpanzees.     

The extended genotype: the heritability of personality accounts for the heritability of recalled family environments in twins reared apart

Abstract How are retrospective accounts of family rearing environments linked to adult personality? We addressed this question by measuring both domains in a sample of 180 reared‐apart twins. Twins completed extensive measures of rearing environments (the Minnesota‐Briggs History Record, the Block Environmental Questionnaire, the Family Environment Scale, and the Physical Facilities Questionnaire) and an omnibus measure of adult personality (the Multidimensional Personality Questionnaire). Retrospective accounts of family environments were partially heritable and all the heritable variance in environmental measures could be accounted for by heritable variance in personality. In addition, differences between twins in their accounts of their rearing environments (nonshared environmental factors) were not significantly linked to differences between twins in their personalities. Hence, family environmental measures appear to be heritable because personality genes influence the way people shape and recall their rearing environments. In addition, differences in reared‐apart twins' retrospectively recalled rearing environments appear to have little impact on differences in their personalities in adulthood.     

Genetic and environmental structure of adjectives describing the domains of the Big Five Model of personality: A nationwide US twin study

We applied multivariate models specifying genetic and environmental influences on adjectives describing each of the five personality domains specified in the Big Five Model of personality (BFM; Extraversion, Neuroticism, Agreeableness, Conscientiousness, and Openness). We selected the specific models to partition the observed covariance among the adjectives describing each domain into genetic and environmental components in order to assess the etiologic basis for each domain's phenotypic coherence. The sample on which our analyses were based was part of the National Survey of Midlife Development in the United States (MIDUS). It consisted of 315 monozygotic and 275 same-sex dizygotic twin pairs. Results revealed both common and specific genetic and environmental influences for each domain, suggesting that all of the domains are etiologically complex. Models specifying the domains as latent phenotypic constructs fit more poorly than models suggesting more complex structures for all domains except Extraversion and Neuroticism. These results raise questions about the BFM as a coherent model of genetic and environmental influences on personality or, alternatively, about the etiological unity of latent phenotypic personality trait constructs beyond Extraversion and Neuroticism.     

Investigating the Big Five Personality Factors and Smoking: Implications for Assessment

Global personality dispositions may be important for understanding population-based individual differences in smoking outcomes, yet few studies have been executed using measures of these global dispositional constructs from the contemporary field of personality. This study explored whether the Big Five personality factors (Extraversion, Neuroticism, Agreeableness, Conscientiousness, and Intellect) were concurrently associated with key smoking (e.g., nicotine dependence, smoking rate, age at first cigarette) and cessation (e.g., self-efficacy to quit, motivation to quit, number of prior quit attempts, length of most recent quit) variables in a sample of regular smokers (n = 130). Of the 35 correlations computed, only 2 were significant: Intellect was positively correlated with motivation to quit and number of 24-hr quit attempts in the last year. These results have implications for using trait variables to study individual differences in smokers.     

Unravelling the Interplay Between Genetic and Environmental Contributions in the Unfolding of Personality Differences from Early Adolescence to Young Adulthood

In two studies, we examined the genetic and environmental sources of the unfolding of personality trait differences from childhood to emerging adulthood. Using self‐reports from over 3000 representative German twin pairs of three birth cohorts, we could replicate previous findings on the primary role of genetic sources accounting for the unfolding of inter‐individual differences in personality traits and stabilizing trait differences during adolescence. More specifically, the genetic variance increased between early (ages 10–12 years) and late (ages 16–18 years) adolescence and stabilized between late adolescence and young adulthood (ages 21–25 years). This trend could be confirmed in a second three‐wave longitudinal study of adolescents' personality self‐reports and parent ratings from about 1400 Norwegian twin families (average ages between 15 and 20 years). Moreover, the longitudinal study provided evidence for increasing genetic differences being primarily due to accumulation of novel genetic influences instead of an amplification of initial genetic variation. This is in line with cumulative interaction effects between twins' correlated genetic makeups and environmental circumstances shared by adolescent twins reared together. In other words, nature × nurture interactions rather than transactions can account for increases in genetic variance and thus personality variance during adolescence. © 2019 European Association of Personality Psychology     

Genetic and environmental influences on the positive traits of the values in action classification,and biometric covariance with normal personality

Virtually all human individual differences have been shown to be moderately heritable. Much of this research, however, focuses on measures of dysfunctional behavior and relatively fewer studies have focused on positive traits. The values in action (VIA) project is a comprehensive and ambitious classification of 24 positive traits, also known as character strengths (Peterson, C., & Seligman, M. E. P. (2004). Character strengths and virtues: A handbook and classification. Washington, DC: American Psychological Association), the majority of which have received no behavior genetic attention. Using a sample of 336 middle-aged twins drawn from the Minnesota Twin Registry who completed the VIA inventory of strengths, we detected significant genetic and non-shared environmental effects for 21 of 24 character strengths with little evidence of shared environmental contributions. Associations with a previously administered measure of normal personality found moderate phenotypic overlap and that genetic influences on personality traits could account for most, but not all, of the heritable variance in character strengths.     

Heritability of the Big Five Personality Dimensions and Their Facets: A Twin Study

ABSTRACT The genetic and environmental etiology of the five-factor model of personality as measured by the revised NEO Personality Inventory (NEO-PI-R) was assessed using 123 pairs of identical twins and 127 pairs of fraternal twins. Broad genetic influence on the five dimensions of Neuroticism, Extraversion, Openness, Agreeableness, and Conscientiousness was estimated at 41%, 53%, 61%, 41%, and 44%, respectively. The facet scales also showed substantial heritability, although for several facets the genetic influence was largely nonadditive. The influence of the environment was consistent across all dimensions and facets. Shared environmental influences accounted for a negligible proportion of the variance in most scales, whereas nonshared environmental influences accounted for the majority of the environmental variance in all scales.     

Situation-based contingencies underlying trait-content manifestation in behavior

Two studies investigated whether situations are associated with the manifestation of Big Five trait contents in behavior. Several times per day for 2 or 5 weeks, participants reported their current Extraversion, Agreeableness, Conscientiousness, and Emotional Stability states and rated the concurrent situation on several characteristics. Multilevel models tested for the average individual's contingency of each Big Five state on each situation characteristic and for whether individuals differed from each other reliably in those contingencies. Results showed that (1) there are psychologically active characteristics of situations on which trait-manifesting behavior is contingent; (2) contingencies on psychologically active characteristics of varying situations are part of the explanation for the sizeable within-person variability in behavior; (3) individuals differ reliably in their contingencies, and such individual differences may partially explain individual differences in amount of variability; and (4) the situation characteristics that are psychologically active differ by trait. These findings suggest that within-person variability in personality states is meaningful and is related to situations, that personality psychology should characterize situations in terms of their relevance to personality states, and that process and individual-difference structure approaches can be integrated in personality psychology.     

The Structure and Sources of Right‐wing Authoritarianism and Social Dominance Orientation

Right‐wing authoritarianism (RWA) and social dominance orientation (SDO) are widely used constructs in research on social and political attitudes. This study examined their hierarchical and correlative structure (across sexes, generations and rater perspectives), as well as how genetic and environmental factors may contribute to individual differences in them (using different rater perspectives and nuclear twin family data). We found a substantive common aspect (beyond shared artificial variance arising from socially desirable responding) underlying both RWA and SDO: aggression against subordinate groups. We discussed how this aspect could help to explain the commonly reported correlation between the two concepts in Western countries. Estimates of genetic and environmental components in RWA and SDO based on self‐reports were quite comparable with those based on peer reports. When controlling for error variance and taking assortative mating into account, individual differences in RWA were primarily due to genetic contributions including genotype–environment correlation, whereas variance in SDO was largely attributable to environmental sources shared and not shared by twins. The findings are discussed in terms of the utility of RWA and SDO as basic constructs to describe individual differences in social attitudes and with respect to the different patterns of genetic and environmental influences that underlie them. Copyright © 2016 European Association of Personality Psychology     

Environment and genes. Determinants of behavior

Recent behavioral genetic research has demonstrated that genetic influence on individual differences in behavioral development is usually significant and often substantial and, paradoxically, also supports the important role of the environment. This article reviews research on the heritability of intellectual factors, personality factors, and psychopathology. It discusses the importance of investigating within-family environmental differences in order to understand the environmental origins of individual differences in development.     

Genetic and Environmental Effects on Openness to Experience, Agreeableness, and Conscientiousness: An Adoption/Twin Study

ABSTRACT Previous research has indicated that extraversion and neuroticism are substantially affected both by genotype and environment. This study assesses genetic and environmental influences on the other three components of the five-factor model of personality: Openness to Experience, Agreeableness, and Conscientiousness. An abbreviated version of the NEO Personality Inventory (NEO-PI) was administered to 82 pairs of identical twins and 171 pairs of fraternal twins reared apart and 132 pairs of identical twins and 167 pairs of fraternal twins reared together. Estimates of genetic and environmental effects for Openness and Conscientiousness were similar to those found in other studies of personality: Genetic influence was substantial and there was little evidence of shared rearing environment. Results for Agreeableness were different: Genetic influence accounted for only 12% of the variance and shared rearing environment accounted for 21% of the variance. Few significant gender or age differences for genetic and environmental parameters were found in model-fitting analyses.     

Nonlinear epigenetic variance: review and simulations

We present a review of empirical evidence that suggests that a substantial portion of phenotypic variance is due to nonlinear (epigenetic) processes during ontogenesis. The role of such processes as a source of phenotypic variance in human behaviour genetic studies is not fully appreciated. In addition to our review, we present simulation studies of nonlinear epigenetic variance using a computational model of neuronal network development. In each simulation study, time series for monozygotic and dizygotic twins were generated and analysed using conventional behaviour genetic modelling. In the results of these analyses, the nonlinear epigenetic variance was subsumed under the non-shared environmental component. As is commonly found in behaviour genetic studies, observed heritabilities and unique environmentabilities increased with time, whereas common environmentabilities decreased. The fact that the phenotypic effects of nonlinear epigenetic processes appear as unsystematic variance in conventional twin analyses complicates the identification and quantification of the ultimate genetic and environmental causes of individual differences. We believe that nonlinear dynamical system theories provide a challenging perspective on the development of individual differences, which may enrich behaviour genetic studies.     

Personality and life satisfaction: a facet-level analysis

At the global level of the Big Five, Extraversion and Neuroticism are the strongest predictors of life satisfaction. However, Extraversion and Neuroticism are multifaceted constructs that combine more specific traits. This article examined the contribution of facets of Extraversion and Neuroticism to life satisfaction in four studies. The depression facet of Neuroticism and the positive emotions/cheerfulness facet of Extraversion were the strongest and most consistent predictors of life satisfaction. These two facets often accounted for more variance in life satisfaction than Neuroticism and Extraversion. The findings suggest that measures of depression and positive emotions/cheerfulness are necessary and sufficient to predict life satisfaction from personality traits. The results also lead to a more refined understanding of the specific personality traits that influence life satisfaction: Depression is more important than anxiety or anger and a cheerful temperament is more important than being active or sociable.     

Analysis of genetic influences on the consistency and variability of the Big Five across different stressful situations

Several studies have demonstrated that individual differences in personality traits, known as the Big Five, have a genetic component. These personality traits are considered important predictors of everyday behaviour. In addition to personality traits there are also factors in the environment that govern behaviour. This dual influence on behaviour is statistically reflected in a P × S interaction. This study examines the genetic and environmental influences on the interactions between a person and his daily life environment for the Big Five. Fifty‐seven identical twin pairs and 43 fraternal twin pairs participated in this study. Trait related behaviour was measured in 30 different situations with the aid of an SR inventory. The heritability coefficients for the main effect of P were in the normal range, varying between 0.35 for Agreeableness and 0.53 for Conscientiousness. The heritability coefficients for the P × S interactions were moderately high, explaining between 26% and 69% of the total P × S variance. The consequences of these results for general and behavioural genetic research on the Big Five will be discussed. Copyright © 2001 John Wiley & Sons, Ltd.     

Happiness is a personal(ity) thing: the genetics of personality and well-being in a representative sample.

Subjective well-being is known to be related to personality traits. However, to date, nobody has examined whether personality and subjective well-being share a common genetic structure. We used a representative sample of 973 twin pairs to test the hypothesis that heritable differences in subjective well-being are entirely accounted for by the genetic architecture of the Five-Factor Model's personality domains. Results supported this model. Subjective well-being was accounted for by unique genetic influences from Neuroticism, Extraversion, and Conscientiousness, and by a common genetic factor that influenced all five personality domains in the directions of low Neuroticism and high Extraversion, Openness, Agreeableness, and Conscientiousness. These findings indicate that subjective well-being is linked to personality by common genes and that personality may form an "affective reserve" relevant to set-point maintenance and changes in set point over time.