A behavior genetic analysis of personality and loneliness

The phenotypic, genetic, and environmental correlations between the Big Five factors of personality and loneliness were examined. At the phenotypic level, loneliness had a strong significant positive correlation with neuroticism, significant moderate negative correlations with agreeableness, conscientiousness, and extraversion, and a small positive correlation with openness. Both loneliness and personality were found to be heritable. Bivariate genetic analyses resulted in significant positive genetic correlations between loneliness and neuroticism and openness, and significant negative genetic correlations with agreeableness, conscientiousness, and extraversion. Significant unique environment correlations were found between loneliness and four of the five personality factors (all negative except neuroticism) and a non-significant correlation with openness. The results suggest common genetic and unique environmental factors play a role in personality and loneliness.     

Humor styles and borderline personality

The present study examined the phenotypic, genetic, and environmental correlations between four humor styles (affiliative, self-enhancing, aggressive, and self-defeating) and four dimensions of borderline personality disorder (affective instability, identity disturbance, negative relationships, self-harm) as well as a total borderline personality disorder score. Participants were 574 same-sex Australian adult twin pairs. At the phenotypic level, the two adaptive humor style dimensions (affiliative and self-enhancing) were found to correlate negatively with borderline personality and the two maladaptive humor style dimensions (aggressive and self-defeating) were found to have positive correlations with borderline personality. Bivariate genetic analyses demonstrated significant genetic, common environment, and unique environmental correlations. These results indicate that a large component of the phenotypic association between borderline personality disorder and humor style arises from the influence of shared familial and environmental factors associated with both phenotypes.     

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.     

A behavioral genetic study of the overlap between personality and parenting

The current study had three aims. The first was to examine the covariation between personality of parents and parenting behaviors. The second aim was to examine the genetic and environmental influences on parenting behaviors. The third aim was to examine the extent to which the association between personality and parenting was mediated by genetic and environmental factors. Personality (Five Factor Model, NEO-FFI) and parenting data were collected as part of a larger German study of 300 adult twin pairs (GOSAT). The current paper analyzes data on a subset of the 300 twin pairs from the GOSAT sample who were concordant for having children (n=98 pairs or 196 individuals). Results indicated modest overlap between personality and parenting. In addition, univariate behavioral genetic analyses indicated moderate genetic influence on select parenting dimensions. Results also indicated that the moderate phenotypic covariation between personality and parenting was attributed largely to nongenetic factors. Implications of the findings for research on parenting and personality are considered.     

Phenotypic and genetic relationships between vocational interests and personality

Relationships between personality and vocational interest factors were examined at the phenotypic and genetic levels. Twins and siblings (N = 516) completed self-report personality and vocational interest scales. Following factor analyses of each scale, five personality and six vocational interest factors were extracted. At the phenotypic level, correlations between personality and vocational interests ranged from zero to .33. Heritability estimates of the scales showed that genetic components accounted for 0–56% of the variance for the vocational interest factors and 44–65% for the personality factors. Genetic correlations between the two areas ranged from zero to .50. The results suggest that personality is related to some vocational interest dimensions and that some of these observed relationships have a common genetic basis.     

The general factor of personality and humor styles

The present study examined the phenotypic, genetic, and environmental correlations between a general factor of personality (GFP) and four humor styles: affiliative, self-enhancing, aggressive, and self-defeating. Participants were 571 same-sex adult twin pairs. Individuals completed the Humor Styles Questionnaire (HSQ) and a short form of the NEO personality scale (from which the GFP was extracted). The GFP was found to be heritable with an estimated value of .31. At the phenotypic level, the GFP was found to correlate significantly with the HSQ scales; positively with affiliative and self-enhancing, and negatively with aggressive and self-defeating. Three of the four phenotypic correlations were found to be attributable to correlated genetic factors, suggesting that these dimensions of humor styles and the GFP may have a common genetic factor.     

Sources of structure: genetic, environmental, and artifactual influences on the covariation of personality traits

The phenotypic structure of personality traits has been well described, but it has not yet been explained causally. Behavior genetic covariance analyses can identify the underlying causes of phenotypic structure; previous behavior genetic research has suggested that the effects from both genetic and nonshared environmental influences mirror the phenotype. However, nonshared environmental effects are usually estimated as a residualterm that may also include systematic bias, such as that introduced by implicit personality theory. To reduce that bias, we supplemented data from Canadian and German twin studies with cross-observer correlations on the Revised NEO Personality Inventory. The hypothesized five-factor structure was found in both the phenotypic and genetic/familial covariances. When the residual covariance was decomposed into true nonshared environmental influences and method bias, only the latter showed the five-factor structure. True nonshared environmental influences are not structured as genetic influences are, although there was some suggestion that they do affect two personality dimensions, Conscientiousness and Love. These data reaffirm the value of behavior genetic analyses for research on the underlying causes of personality traits.     

Normal and abnormal personality traits: evidence for genetic and environmental relationships in the Minnesota Study of Twins Reared Apart

ABSTRACT Recent studies have demonstrated substantial correlations between normal and abnormal personality traits. Yet little is known about how these correlations are mediated genetically and environmentally: Do normal and abnormal personality traits stem from the same underlying genes and environments? We addressed this question using data from 128 monozygotic and dizygotic twin pairs in the Minnesota Study of Twins Reared Apart (MISTRA). Additive genetic and nonshared environmental correlations between scales of the Minnesota Multiphasic Personality Inventory (MMPI)—an index of abnormal personality—and the Multidimensional Personality Questionnaire (MPQ)—an index of normal personality—were estimated. Results indicated that phenotypic correlations between normal and abnormal personality were mediated by genetic as well as environmental factors, although the magnitude of genetic mediation tended to be larger overall. Moreover, the patterns of phenotypic, genetic, and environmental relationships among the scales were similar, suggesting that influences on normal and abnormal personality act through systems common to both. It is suggested that future research focus on the neurogenetic substrates of these shared systems and how dysfunction in these systems influences development of disordered personality.     

Is the genetic structure of human personality universal? A cross-cultural twin study from North America, Europe, and Asia

This study examined whether universality of the 5-factor model (FFM) of personality operationalized by the Revised NEO Personality Inventory is due to genetic influences that are invariant across diverse nations. Factor analyses were conducted on matrices of phenotypic, genetic, and environmental correlations estimated in a sample of 1,209 monozygotic and 701 dizygotic twin pairs from Canada, Germany, and Japan. Five genetic and environmental factors were extracted for each sample. High congruence coefficients were observed when phenotypic, genetic, and environmental factors were compared in each sample as well as when each factor was compared across samples. These results suggest that the FFM has a solid biological basis and may represent a common heritage of the human species.     

Genetic and Environmental Influences on Two Measures of Speed of Information Processing and their Relation to Psychometric Intelligence: Evidence from the German Observational Study of Adult Twins

Speed of information processing, as measured by reaction times (RTs) in elementary cognitive tasks (ECTs), has been found to be an important correlate of human psychometric intelligence. While the heritability of psychometric intelligence is well understood, we know only a little about genetic and environmental influences on ECT performance, particularly about genetic and environmental contributions to ECT–intelligence relation. These questions were studied by employing two widely used ECTs (Sternberg's memory scanning and Posner's letter-matching task) as well as two psychometric intelligence tests (Advanced Progressive Matrices and Leistungs–Prüf System) in a large sample of 169 monozygotic (MZ) and 131 dizygotic (DZ) twin pairs. As expected, RTs correlated negatively with psychometric intelligence. Moreover, heritability estimates were substantial for both psychometric intelligence and RTs in ECTs. Finally, multivariate genetic analyses suggested that most of the phenotypic correlation between mental speed and intelligence is due to genetic factors.     

Phenotypic, genetic, and nonshared environmental parallels in the structure of personality: a view from the multidimensional personality questionnaire

How closely do observed, phenotypic personality structures correspond with underlying, genetic, and environmental personality structures? This question was addressed using data from 2,490 pairs of twins from the Minnesota Twin Registry, who completed A. Tellegen's (1982) Multidimensional Personality Questionnaire (MPQ). Phenotypic, additive genetic, and nonshared environmental correlations were computed among the MPQ's eleven primary scales. Principal component analyses of all three matrices revealed three broad, higher-order components that were readily interpreted as negative emotionality, positive emotionality, and constraint. The components from all three matrices were highly comparable, suggesting that the observed, phenotypic structure of personality corresponds closely with the underlying, etiological structure of personality.     

Genetic and environmental influences on executive functions and intelligence in middle childhood

Executive functions (EFs) and intelligence (IQ) are phenotypically correlated. In twin studies, latent variables for EFs and IQ display moderate to high heritability estimates; however, they show variable genetic correlations in twin studies spanning childhood to middle age. We analyzed data from over 11,000 children (9- to 10-year-olds, including 749 twin pairs) in the Adolescent Brain Cognitive Development (ABCD) Study to examine the phenotypic and genetic relations between EFs and IQ in childhood. We identified two EF factors—Common EF and Updating-Specific—which were both related to IQ (rs = 0.64–0.81). Common EF and IQ were heritable (53%–67%), and their genetic correlation (rG = 0.86) was not significantly different than 1. These results suggest that EFs and IQ are phenotypically but not genetically separable in middle childhood, meaning that this phenotypic separability may be influenced by environmental factors.     

The relationship between self-report mood and personality

Past research pertaining to personality and mood has been concerned with the relationship between specific personality traits and specific mood states. The present examines the relationship between self-report measures of personality and mood. University students (82 males, 118 females), completed a personality questionnaire consisting of 20 personality bipolar adjectives and a mood inventory measuring six mood dimensions. Factor analysis of the personality adjectives revealed four factors, which were then correlated with the mood scales. Results of this analysis revealed significant correlations between the personality factors and mood dimensions suggesting that personality is related to some aspects of mood.     

Genetic relationships between personality and eating attitudes and behaviors

Genetic and environmental factors underlying relationships between personality traits and disordered eating were examined in 256 female adolescent twin pairs (166 monozygotic, 90 dizygotic). Eating behaviors were assessed with the Total Score, Body Dissatisfaction, Weight Preoccupation, Binge Eating, and Compensatory Behavior subscales from the Minnesota Eating Disorders Inventory (M-EDI; K. L. Klump, M. McGue, & W. G. Iacono, 2000). Personality characteristics were assessed with the Negative Emotionality, Positive Emotionality, and Constraint scales from the Multidimensional Personality Questionnaire (MPQ; A. Tellegen, 1982). Model-fitting analyses indicated that although genetic factors were more likely to contribute to MPQ and M-EDI phenotypic associations than environmental factors, shared genetic variance between the 2 phenotypes was limited. MPQ personality characteristics may represent only some of several genetic risk factors for eating pathology.     

Genetic and environmental contributions to the co-occurrence of depressive personality disorder and DSM-IV personality disorders

One of the main controversies with regard to depressive personality disorder (DPD) concerns the co-occurrence with the established DSM-IV personality disorders (PDs). The main aim of this study was to examine to what extent DPD and the DSM-IV PDs share genetic and environmental risk factors, using multivariate twin modeling. The DSM-IV Structured Interview for Personality was applied to 2,794 young adult twins. Paranoid PD from Cluster A, borderline PD from Cluster B, and all three PDs from Cluster C were independently and significantly associated with DPD in multiple regression analysis. The genetic correlations between DPD and the other PDs were strong (.53-.83), while the environmental correlations were moderate (.36-.40). Close to 50% of the total variance in DPD was disorder specific. However, only 5% was due to disorder-specific genetic factors, indicating that a substantial part of the genetic vulnerability to DPD also increases the vulnerability to other PDs.     

The genetic links between the big five personality traits and general interest domains

This is the first genetically informative study in which multiple informants were used to quantify the genetic and environmental sources of individual differences in general interests as well as the phenotypic and genetic links between general interests and Big Five personality traits. Self-reports and two peer ratings from 844 individuals, including 225 monozygotic and 113 dizygotic complete twin pairs, were collected. Multiple-rater scores (composites) revealed that the averaged levels of genetic and environmental effects on seven broad interest domains were similar to those on personality traits. Multivariate analyses showed that about 35% of the genetic and 9% of the environmental variance in interests were explained by personality domains, in particular by Openness. The findings suggest that interests cannot easily be considered as a byproduct of the interactions between personality genotypes and the environmental influences but rather as an internal regulation of behavior with an own genetic basis.     

Physical activity and personality: A behaviour genetic analysis

ObjectivesThe aim of this study was to obtain a heritability estimate of exercise behaviour in twins and to examine the genetic and environmental contributions to phenotypic associations between personality and exercise behaviour.DesignTwin study was used, the sample including 339 twin pairs (105 MZ and 234 DZ), between 15 and 22 years of age (M = 18.6, SD = 2.31).MethodThe participants filled in a NEO-FFI personality inventory and answered two questions about the frequency (FPE) and intensity (IPE) of physical exercise. We also calculated the composite physical exercise score (CS) representing a combination of FPE and IPE items.ResultsThe broad heritability estimates of three physical exercise variables (FPE, IPE, CS) were significant, with results in the 0.55 to 0.69 range. We found significant phenotypic associations with neuroticism and extraversion. Contrary to our expectations, correlations with conscientiousness were not significant. People scoring higher on extraversion and lower on neuroticism reported exercising more often and more intensely. Phenotypic association between personality traits and physical exercise variables were due to overlapping genetic influences.ConclusionsOur results indicate that the genetic factors contributing to an active lifestyle overlap with those contributing to personality traits extraversion and neuroticism, in line with the “nature” hypothesis which infers the presence of biological differences in predisposition for regular physical activity.     

Genetic and Environmental Contributions to Individual Differences: The Three Major Dimensions of Personality

ABSTRACT This article deals with the contribution of genetic and environmental factors to individual differences in the three major dimensions of personality (Psychoticism, Extraversion, and Neuroticism) Twin studies indicate, and family studies confirm within limits, the strong genetic determination of these and many other personality factors, additive genetic variance accounting for roughly half the total phenotypic variance On the environmental side, shared family environment plays little or no part, all environmental effects being within-family Assortative mating, important in the formation of social attitudes, has little impact on personality Dominance may be important for Extraversion Epistasis (emergenesis) may account for the comparative low values of dizygotic (DZ) twins' correlations Evidence for differential heritability of traits is present, but not very strong It is concluded that behavioral genetics forms a vital part of the psychological understanding of the causes of individual differences in personality     

Why is personality tied to sleep quality? A biometric analysis of twins

Despite consistent links between personality traits and poor sleep, little is known about genetic and environmental influences that may produce them. This study examined how much genetic background and environmental experiences contributed to phenotypic linkages between personality and subjective sleep quality. Seven hundred and thirty-four twin pairs from the Minnesota Study of Twin Aging and Development rated their sleep quality and provided personality reports. Bi-variate analyses revealed that genetic factors accounted for the majority of observed associations between subjective sleep quality and traits, but also that non-shared environmental experience played a role that varied across traits. The findings strongly implicate genotype in tying subjective sleep quality to personality variation, alongside non-shared environmental influences, and suggest indicate influences unique to individual traits.     

A general factor of personality,social desirability,cognitive ability,and the survey of work styles in an employment selection setting

How a general factor of personality (GFP) correlated with employment screening measures in an applied setting was examined. Participants were 540 adult insurance sales job applicants who completed scales from two personality measures, the five scales from the Survey of Work Styles (SWS), an intelligence measure, and a social desirability scale. A joint factor analysis of the personality questionnaires produced four first order factors. A single GFP was also extracted. Strong correlations were found between some of the personality factors and the SWS scales. Strong significant correlations were found between the GFP and three of the four personality factors with social desirability. Neither the GFP nor the personality factors correlated significantly with cognitive abilities.