Comparability of Self‐Reported Conscientiousness Across 21 Countries

In cross‐national studies, mean levels of self‐reported phenomena are often not congruent with more objective criteria. One prominent explanation for such findings is that people make self‐report judgements in relation to culture‐specific standards (often called the reference group effect), thereby undermining the cross‐cultural comparability of the judgements. We employed a simple method called anchoring vignettes in order to test whether people from 21 different countries have varying standards for Conscientiousness, a Big Five personality trait that has repeatedly shown unexpected nation‐level relationships with external criteria. Participants rated their own Conscientiousness and that of 30 hypothetical persons portrayed in short vignettes. The latter type of ratings was expected to reveal individual differences in standards of Conscientiousness. The vignettes were rated relatively similarly in all countries, suggesting no substantial culture‐related differences in standards for Conscientiousness. Controlling for the small differences in standards did not substantially change the rankings of countries on mean self‐ratings or the predictive validities of these rankings for objective criteria. These findings are not consistent with mean self‐rated Conscientiousness scores being influenced by culture‐specific standards. The technique of anchoring vignettes can be used in various types of studies to assess the potentially confounding effects of reference levels. Copyright © 2011 John Wiley & Sons, Ltd.     

Implicit learning, thought-focused attention and obsessive-compulsive disorder: a replication and extension

Although significant empirical support exists for both cognitive and neurobiological models of obsessive-compulsive disorder (OCD), there have been few efforts to integrate findings. In this investigation, we attempted to link models by examining relationships between performance on information processing tasks posited to be markers of OCD-related neuropathology and a self-report measure of excessive thought-focused attention (cognitive self-consciousness; CSC). Congruent with predictions and prior research, OCD patients' performance was impaired in comparison to an anxious control group on the Serial Reaction Time (SRT) Task, a measure of implicit procedural learning. Following completion of the SRT, participants' awareness of the embedded stimulus pattern was assessed. As predicted, participants with OCD demonstrated superior performance on this task. Scoring on a measure of CSC correlated with performance on both tasks, although the amount of variance accounted for was modest. Evaluation of OCD symptom subgroups revealed greater procedural learning impairment in a hoarding subgroup. Implications for theory and treatment are discussed.     

Personality in Germany and Minnesota: an IRT-based comparison of MPQ self-reports

We compared personality across cultures to explore the extent of cultural differences. This study used samples matched on gender and age from Germany and Minnesota to compare traditional scale scores and IRT-based parameters for Tellegen's (1982) Multidimensional Personality Questionnaire scales. Because the samples consisted of twins, we were able to replicate the findings from the subsamples consisting of one member of each pair with the subsamples consisting of their co-twins. When the full scales were considered, Germans were higher in Aggression and Absorption and Minnesotans were higher in Well-being, Control, and Traditionalism, but, except for those in Traditionalism, different item-difficulty parameters explained most of these differences. IRT highlighted less than optimal scale properties as well as differentially functioning items. We discuss the theoretical implications of these findings.     

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.     

Covariance structure of neuroticism and agreeableness: a twin and molecular genetic analysis of the role of the serotonin transporter gene

The Revised NEO Personality Inventory domains of Neuroticism and Agreeableness are considered factorially distinct despite several intercorrelations between these domains. The genetic correlation, an index of the degree to which these intercorrelations are caused by genetic influences, was estimated using data from 913 monozygotic and 562 dizygotic volunteer twin pairs from Canada, Germany, and Japan. The serotonin transporter gene, 5-HTTLPR, was assayed in a sample of 388 nontwin sibling pairs from the United States to determine the contribution of the serotonin transporter locus to the covariation between the Neuroticism and Agreeableness scales. In all four samples, genetic influences contributed to the covariance of Neuroticism and Agreeableness, with the serotonin transporter gene accounting for 10% of the relationship between these domains.     

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.     

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

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.     

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 observed personality: evidence from the German Observational Study of Adult Twins

Previous behavior-genetic research on adult personality relied primarily on self-reports or peer reports that may be subject to contrast effects, resulting in biased estimates of genetic and environmental influences. In the German Observational Study of Adult Twins (GOSAT), personality traits of 168 monozygotic (MZ) and 132 dizygotic (DZ) twin pairs were rated on 35 adjective scales, largely markers of the Big 5. The ratings were provided by 120 judges who never met the twins but observed videotaped behaviors of 1 twin of each pair in 1 of 15 different settings. The aggregated video-based trait ratings were highly reliable, and substantial correlations were obtained between MZ as well as DZ twins. Model-fit analyses suggested about 40% genetic, 25% shared environmental, and 35% nonshared environmental influence. Extraversion was the only trait that seemed not to be influenced by shared environment.     

Effects of September 11 on patients with obsessive compulsive disorder

Effects of the September 11, 2001 terrorist attacks in the USA were investigated in 25 patients with obsessive compulsive disorder and 27 normal controls 4-6 months after the attacks. Participants completed a 15-item questionnaire to retrospectively assess changes in mood, cognition, behavior and somatic complaints since September 11, 2001. Overall, both patients with obsessive compulsive disorder and normal controls reported minor changes in mood, behavior and somatic complaints. However, normal controls reported severe to extreme initial impact, slightly more cognitive symptoms (uncertainty about the future, intrusive recollections and greater desire to be with loved ones) and a slightly greater degree of overall impact on emotion and behavior at 1, 2 and 3 months after September 11 than did patients with obsessive compulsive disorder. Results support previous research that has found a relatively minor lasting impact of September 11 on both clinical and normal populations. Differences in cognition and coping mechanisms between normal controls and patients with obsessive compulsive disorder are proposed.