Jaap J. A. Denissen

The evolutionary genetics of personality

Genetic influences on personality differences are ubiquitous, but their nature is not well understood. A theoretical framework might help, and can be provided by evolutionary genetics. We assess three evolutionary genetic mechanisms that could explain genetic variance in personality differences: selective neutrality, mutation‐selection balance, and balancing selection. Based on evolutionary genetic theory and empirical results from behaviour genetics and personality psychology, we conclude that selective neutrality is largely irrelevant, that mutation‐selection balance seems best at explaining genetic variance in intelligence, and that balancing selection by environmental heterogeneity seems best at explaining genetic variance in personality traits. We propose a general model of heritable personality differences that conceptualises intelligence as fitness components and personality traits as individual reaction norms of genotypes across environments, with different fitness consequences in different environmental niches. We also discuss the place of mental health in the model. This evolutionary genetic framework highlights the role of gene‐environment interactions in the study of personality, yields new insight into the person‐situation‐debate and the structure of personality, and has practical implications for both quantitative and molecular genetic studies of personality. Copyright

Emerging late adolescent friendship networks and Big Five personality traits : a social network approach

The current study focuses on the emergence of friendship networks among just-acquainted individuals, investigating the effects of Big Five personality traits on friendship selection processes. Sociometric nominations and self-ratings on personality traits were gathered from 205 late adolescents (mean age=19 years) at 5 time points during the first year of university. SIENA, a novel multilevel statistical procedure for social network analysis, was used to examine effects of Big Five traits on friendship selection. Results indicated that friendship networks between just-acquainted individuals became increasingly more cohesive within the first 3 months and then stabilized. Whereas individuals high on Extraversion tended to select more friends than those low on this trait, individuals high on Agreeableness tended to be selected more as friends. In addition, individuals tended to select friends with similar levels of Agreeableness, Extraversion, and Openness.

Development and Validation of a Dutch Translation of the Big Five Inventory (BFI)

In this article, we describe the translation and validation of the Dutch Big Five Inventory (BFI; John & Srivastava, 1999), a short instrument designed to measure the Big Five factors of personality. We obtained evidence of the instruments good psychometric properties in terms of factorial equivalence to the English original and other BFI translations and the relative independence and internal consistency of the five scales. The findings suggest that the instrument can be used in diverse age groups without substantial changes in factor structure. The Dutch BFI scales showed similar demographic correlates as the English original, with higher Agreeableness and Conscientiousness and lower Neuroticism values in older participants, higher Neuroticism values in women, and higher Openness and Conscientiousness values in better educated participants. Use of the Dutch BFI will allow researchers to integrate their findings with the extant Big Five research literature. The brevity of the instrument will be appealing to researchers who are concerned about taxing the time and motivation of their participants.

The effects of weather on daily mood: A multilevel approach.

The present study examines the effects of six weather parameters (temperature, wind power, sunlight, precipitation, air pressure, and photoperiod) on mood (positive affect, negative affect, and tiredness). Data were gathered from an online diary study (N = 1,233), linked to weather station data, and analyzed by means of multilevel analysis. Multivariate and univariate analyses enabled distinction between unique and shared effects. The results revealed main effects of temperature, wind power, and sunlight on negative affect. Sunlight had a main effect on tiredness and mediated the effects of precipitation and air pressure on tiredness. In terms of explained variance, however, the average effect of weather on mood was only small, though significant random variation was found across individuals, especially regarding the effect of photoperiod. However, these individual differences in weather sensitivity could not be explained by the Five Factor Model personality traits, gender, or age.

Inhibited and Aggressive Preschool Children at 23 Years of Age: Personality and Social Transitions into Adulthood

In a 19-year longitudinal study, the 15% most inhibited and the 15% most aggressive children at ages 4-6 years were followed up until age 23 years and were compared with controls who were below average in preschool inhibition or aggressiveness. As adults, inhibited boys and girls were judged as inhibited by their parents and showed a delay in establishing a first stable partnership and finding a first full-time job. However, only the upper 8% in terms of inhibition tended to show internalizing problems, including self-rated inhibition. Aggressive boys showed an externalizing personality profile in the parental and self-judgments, were educational and occupational underachievers, and showed a higher adult delinquency rate than the controls, even after sex and socioeconomic status were controlled. The results suggest delayed social transitions without internalizing problems for most male and female inhibited children and a significant long-term risk of an externalizing profile for aggressive children.

Self-esteem reactions to social interactions: Evidence for sociometer mechanisms across days, people, and nations.

People have a fundamental need to belong that motivates them to seek out social interactions with close others (Baumeister & Leary, 1995). Leary and Baumeisters (2000) sociometer theory (SMT) poses that people who succeed in satisfying this need have higher self-esteem (SE). This prediction was tested across three hierarchical levels: intraindividual, interindividual, and international. Indicators of social interaction quantity, quality, and the interaction between quality and quantity were collected for relationships with friends, family members, and romantic partners. On the intraindividual level, relationship quality and the interaction between quantity and quality emerged as significant predictors of daily fluctuations in SE. Cross-lagged analyses indicated that this association is at least partly due to the effect of social inclusion on changes in SE. On an interindividual level, people who generally reported higher quality relationships also had higher levels of trait SE. On an international level, countries whose inhabitants regularly interact with friends were characterized by higher nationwide SE levels than countries without such practices, even when happiness, individualism, gross domestic product, and neuroticism were controlled.

Development and validation of the childhood narcissism scale

In this article, we describe the development and validation of a short (10 item) but comprehensive self-report measure of childhood narcissism. The Childhood Narcissism Scale (CNS) is a 1-dimensional measure of stable individual differences in childhood narcissism with strong internal consistency reliability (Studies 1–4). The CNS is virtually unrelated to conventional measures of self-esteem but is positively related to self-appraised superiority, social evaluative concern and self-esteem contingency, agentic interpersonal goals, and emotional extremity (Study 5). Furthermore, the CNS is negatively related to empathic concern and positively related to aggression following ego threat (Study 6). These results suggest that childhood narcissism has similar psychological and interpersonal correlates as adult narcissism. The CNS provides researchers a convenient tool for measuring narcissism in children and young adolescents with strong preliminary psychometric characteristics.

In the Eye of the Beholder: Perceived, Actual, and Peer-Rated Similarity in Personality, Communication, and Friendship Intensity During the Acquaintanceship Process

The authors examined associations of perceived similarity, actual similarity, and peer-rated similarity in personality with friendship intensity during the acquaintanceship process in a naturalistic setting. Self- and peer-rated personality data were gathered from undergraduates (mean age = 18.9) at 5 time points during the first year of university using a round-robin design. Whereas perceived similarity and peer-rated similarity in personality were concurrently associated with more friendship intensity for just-acquainted individuals, actual similarity in personality was not. Further, bidirectional cross-lagged associations between perceived similarity and friendship intensity were found. Peer-rated similarity was also associated with increases in friendship intensity, and this association was mediated by communication frequency. These results indicate that specific types of similarity in personality are differentially associated with friendship intensity during early phases of acquaintanceship in a real-life setting. Further, insight was provided in the direction of causality between similarity and attraction: Perceived and peer-rated similarity seem to breed friendship intensity, whereas friendship intensity seems to breed perceived similarity only. Finally, peers expectations seem to affect individuals communicative behaviors, which in turn affect friendship formation.

Single-item big five ratings in a social network design

To develop and validate an ultra‐short measure to assess the Big Five in social network designs, the unipolar items of the Ten‐Item Personality Inventory were adapted to create a bipolar single‐item scale (TIPI‐r), including a new Openness item. Reliability was examined in terms of the internal consistency and test–retest stability of self‐ratings and peer‐rating composites (trait reputations). Validity was examined by means of convergence between TIPI‐r and Big Five Inventory (BFI) scores, self‐peer agreement and projection (intra‐ individual correlation between self‐ and peer‐ratings). The psychometric quality of the TIPI‐r differed somewhat between scales and the different reliability and validity criteria. The high reliability of the peer‐rating composites motivates to use the TIPI‐r in future studies employing social network designs. Copyright

Midlife Concerns and Short-term Personality Change in Middle Adulthood

In this study, it was expected that personality change would be related to parents concerns in various domains of midlife functioning. Personality was found to be moderately stable, but small but reliable change was also found. Fathers change in personality was uniquely related to their life satisfaction, work stress and perceptions of the level of their adolescent childrens internalising problems, but not to perceived partner support. By comparison, mothers change in personality was only uniquely related to their life satisfaction. These results suggest that personality change in midlife is associated with the successful adaptation to midlife concerns. This pattern is consistent with social investment theories of personality development, though cross‐lagged longitudinal research is needed to substantiate this conclusion. Copyright