Joshua J. Jackson

Sociogenomic Personality Psychology

In this article, we address a number of issues surrounding biological models of personality traits. Most traditional and many contemporary biological models of personality traits assume that biological systems underlying personality traits are causal and immutable. In contrast, sociogenomic biology, which we introduce to readers in this article, directly contradicts the widely held assumption that something that is biological, heritable, or temperamental, is unchangeable. We provide examples of how seemingly unchanging biological systems, such as DNA, are both dependent on environments for elicitation and can be modified by environmental changes. Finally, we synthesize sociogenomic biology with personality psychology in a model of personality traits that integrates this more modern perspective on biology, physiology, and environment that we term sociogenomic personality psychology. We end the article with a discussion of the future directions of sociogenomic personality psychology.

Can an old dog learn (and want to experience) new tricks? Cognitive training increases openness to experience in older adults

The present study investigated whether an intervention aimed to increase cognitive ability in older adults also changes the personality trait of openness to experience. Older adults completed a 16-week program in inductive reasoning training supplemented by weekly crossword and Sudoku puzzles. Changes in openness to experience were modeled across four assessments over 30 weeks using latent growth curve models. Results indicate that participants in the intervention condition increased in the trait of openness compared with a waitlist control group. The study is one of the first to demonstrate that personality traits can change through nonpsychopharmocological interventions.

Military Training and Personality Trait Development Does the Military Make the Man, or Does the Man Make the Military?

Military experience is an important turning point in a person’s life and, consequently, is associated with important life outcomes. Using a large longitudinal sample of German males, we examined whether personality traits played a role during this period. Results indicated that personality traits prospectively predicted the decision to enter the military. People lower in agreeableness, neuroticism, and openness to experience during high school were more likely to enter the military after graduation. In addition, military training was associated with changes in personality. Compared with a control group, military recruits had lower levels of agreeableness after training. These levels persisted 5 years after training, even after participants entered college or the labor market. This study is one of the first to identify life experiences associated with changes in personality traits. Moreover, our results suggest that military experiences may have a long-lasting influence on individual-level characteristics.

Not all conscientiousness scales change alike: a multimethod, multisample study of age differences in the facets of conscientiousness.

Previous research has shown that traits from the domain of conscientiousness tend to increase with age. However, previous research has not tested whether all aspects of conscientiousness change with age. The present research tests age differences in multiple facets of conscientiousness (industriousness, orderliness, impulse control, reliability, and conventionality) using multiple methods and multiple samples. In a community sample (N = 274) and a representative statewide sample (N = 613) of 18- to 94-year-olds, self-reported industriousness, impulse control, and reliability showed age differences from early adulthood to middle age, whereas orderliness did not. The transition into late adulthood was characterized by increases in impulse control, reliability, and conventionality. In contrast, age differences in observer-rated personality occurred mainly in older adulthood. Age differences held across both ethnicity and levels of socioeconomic status.

Serotonin transporter gene associations with psychopathic traits in youth vary as a function of socioeconomic resources.

Although prior research has examined the genetic correlates of antisocial behavior, molecular genetics influences on psychopathic traits remain largely unknown. Consequently, we investigated the influence of polymorphic variation at the serotonin transporter protein gene (SLC6A4) and socioeconomic resources (SES) on psychopathic traits in youth across two distinct samples in two separate studies. In Study 1, a main effect of serotonin transporter (5-HTTLPR) genotype was associated with the impulsivity dimension of psychopathy. That is, individuals homozygous for the short allele evidenced more impulsivity than did those homozygous for the long allele. In contrast, a gene-environment interaction was associated with the callous-unemotional and narcissistic features of psychopathy. Callous-unemotional and narcissistic traits increased as SES decreased only among youths with the homozygous-long (l/l) genotype, a novel finding replicated and extended in Study 2. These studies provide preliminary results that the l/l genotype confers risk for the emotional deficits and predatory interpersonal traits associated with psychopathy among youths raised in disadvantaged environments.

Mechanisms of health: Education and health-related behaviours partially mediate the relationship between conscientiousness and self-reported physical health

The personality trait of conscientiousness is an important predictor of health and longevity. The present research examined how conscientiousness, in combination with educational attainment and health-related behaviours, predicted self-reported physical health across adulthood. These relations were investigated in two studies, one using a large, representative sample of Illinois residents (N = 617) and the other using a community sample with a multi-method assessment of conscientiousness (N = 274). Across both studies, structural path analyses provided evidence for a model wherein conscientiousness predicted health, in part, through its relationship to both educational attainment and health-related behaviours. The findings suggest conscientiousness predicts health through a diverse set of mechanisms including, but not limited to, educational attainment and health-related behaviours.

Longitudinal correlated changes in conscientiousness, preventative health-related behaviors, and self-perceived physical health.

OBJECTIVE Previous research has found that conscientiousness has positive associations with preventative health-related behaviors and self-perceived health, but little is known about the links between changes in these variables over time. In the present study, we examined how levels and changes in conscientiousness were linked to levels and changes in both preventative health-related behaviors and self-perceived physical health. METHOD Personality and health questionnaires were administered to participants in two waves, with an interval of approximately three years. Participants ranged in age from 19 to 94. To elucidate the tripartite relations between conscientiousness, preventative health-related behaviors, and self-perceived physical health, we used latent change models to estimate levels and changes of these latent constructs over time. RESULTS Changes in conscientiousness were significantly and positively correlated with changes in preventative health behaviors and changes in self-perceived physical health. Changes in preventative health behaviors partially mediated the relation between changes in conscientiousness and changes in self-perceived physical health. CONCLUSIONS This longitudinal study extends previous research on conscientiousness and health by exploring the relations between latent variables over a 3-year period. It provides evidence that increases in conscientiousness and preventative health-related behaviors are associated with improvements in self-perceived health over the same time period.

Personality Traits Predict the Onset of Disease

While personality traits have been linked concurrently to health status and prospectively to outcomes such as mortality, it is currently unknown whether traits predict the diagnosis of a number of specific diseases (e.g., lung disease, heart disease, and stroke) that may account for their mortality effects more generally. A sample (N = 6,904) of participants from the Health and Retirement Study, a longitudinal study of older adults, completed personality measures and reported on current health conditions. Four years later, participants were followed up to see if they developed a new disease. Initial cross-sectional analyses replicated past findings that personality traits differ across disease groups. Longitudinal logistic regression analyses predicting new disease diagnosis suggest that traits are associated with the risk of developing disease—most notably the traits of conscientiousness, neuroticism, and openness. Findings are discussed as a means to identify pathways between personality and health.

Why do personality traits predict divorce? Multiple pathways through satisfaction.

While previous studies indicate that personality traits influence the likelihood of divorce, the processes that drive this relationship have yet to be examined. Accordingly, the current study utilized a nationally representative, longitudinal sample (N = 8,206) to test whether relationship satisfaction is a pathway by which personality traits influence relationship dissolution. Specifically, we examined 2 different pathways: the enduring dynamics and emergent distress pathways. The enduring dynamics pathway specifies that the association between personality and relationship satisfaction reflects ongoing relationship dynamics, which are presumed to be stable across a relationship. In contrast, the emergent distress pathway proposes that personality leads to worsening dynamics across the course of a relationship, which is indicated by changes in satisfaction. For each pathway, we assessed actor, partner, and combined effects for the Big Five. Results replicate previous research in that personality traits prospectively predict relationship dissolution. Both the enduring dynamics and emergent distress pathways served to explain this relationship, though the enduring dynamics model evidenced the largest effects. The emergent distress pathway was stronger for couples who experienced certain life events, suggesting that personality plays a role in adapting to changing life circumstances. Moreover, results suggest that the personality of the dyad is important in this process: Above and beyond actor effects, partner effects influenced relationship functioning (although the influence of combined effects was less clear). In sum, the current study demonstrates that personality traits shape the overall quality of ones relationship, which in turn influences the likelihood of relationship dissolution.

In the zone: flow state and cognition in older adults.

The current study investigated the nature of the flow state among older adults. Flow is a pleasurable experiential state that occurs during full-capacity engagement in which an individual is performing at a level that is matched with the demands of the task. Each participant completed a scale assessing dimensions of flow in a particular activity selected by the participant. More cognitively demanding activities elicited higher levels of flow for those with higher fluid ability, but lower levels of flow for those with lower fluid ability. This pattern was reversed for activities that were low in demand. Our data highlight the potential importance of considering motivational states such as flow in understanding cognitive optimization in adulthood.