Life events sometimes alter the trajectory of personality development: Effect sizes for 25 life events estimated using a large, frequently assessed sample

OBJECTIVE

Personality changes across the life span. Life events, such as marriage, becoming a parent, and retirement, have been proposed as facilitating personality growth via the adoption of novel social roles. However, empirical evidence linking life events with personality development is sparse. Most studies have relied on few assessments separated by long time intervals and have focused on a single life event. In contrast, the content of life is composed of small, recurrent experiences (e.g., getting sick or practicing a hobby), with relatively few major events (e.g., childbirth). Small, frequently experienced life events may play an important and overlooked role in personality development.

METHOD

The present study examined the extent to which 25 major and minor life events alter the trajectory of personality development in a large, frequently assessed sample (Nsample  = 4904, Nassessments  = 47,814, median retest interval = 35 days).

RESULTS

Using a flexible analytic strategy to accommodate the repeated occurrence of life events, we found that the trajectory of personality development shifted in response to a single occurrence of some major life events (e.g., divorce), and recurrent, "minor" life experiences (e.g., one's partner doing something special).

CONCLUSION

Both stark role changes and frequently reinforced minor experiences can lead to personality change.

Basic or Adaptation: The Assessment and Heritability of a Brief Measure of Agency

The interpersonal circumplex describes two major axes of personality that guide much of social behavior. Agency, one half of the interpersonal circumplex, refers to relatively stable behavioral patterns that center on self-focused dominance and assertiveness. Past empirical work on agency tends to treat the dimension as a characteristic adaptation, rather than a basic component of personality, in part due to the relatively large gender difference in agency with masculine individuals tending to behave more agentic. However, the psychometric overlap between agency and the most closely linked big five dimension, extraversion, is not well-established, and no behavior genetic work has documented evidence concerning the role of genetic and environmental influences. It is unclear whether agency is more similar to a personality trait, with no evidence of shared environmental influence and moderate heritability, or a characteristic adaptation, with some evidence for shared environmental influence and possibly lower heritability. We used the Midlife Development in the United States study to examine agency, big five, and generativity with replication and robustness check (Nnon-twins = 5,194; Ntwins = 1,914; NMilwaukee = 592). Results indicated that agency was higher in men (d = -.24), moderately heritable (44.4%), strongly correlated with extraversion (r = .51), moderately correlated with generativity (r = .36), and that approximately 40% of the variance in agency was shared with the big five. Agency also changed strongly with extraversion and openness, but less so generativity. Altogether, these results indicate that agency functions similar to other basic personality dimensions but is not clearly a dispositional trait.

Triangulating causality between childhood obesity and neurobehavior: Behavioral genetic and longitudinal evidence

Childhood obesity is a serious health concern that is not yet fully understood. Previous research has linked obesity with neurobehavioral factors such as behavior, cognition, and brain morphology. The causal directions of these relationships remain mostly untested. We filled this gap by using the Adolescent Brain Cognitive Development study cohort comprising 11,875 children aged 9-10. First, correlations between the age- and sex-specific 95th BMI percentile (%BMIp95) and neurobehavioral measures were cross-sectionally analyzed. Effects were then aggregated by neurobehavioral domain for causal analyses. Behavioral genetic Direction of Causation modeling was used to test the direction of each relationship. Findings were validated by longitudinal cross-lagged panel modeling. %BMIp95 correlated with impulsivity, motivation, psychopathology, eating behavior, and cognitive tests (executive functioning, language, memory, perception, working memory). Greater %BMIp95 was also associated with reduced cortical thickness in frontal and temporal brain areas but with increased thickness in parietal and occipital areas. Similar although weaker patterns emerged for cortical surface area and volume. Behavioral genetic modeling suggested causal effects of %BMIp95 on eating behavior (β = 0.26), cognition (β = 0.05), cortical thickness (β = 0.15), and cortical surface area (β = 0.07). Personality/psychopathology (β = 0.09) and eating behavior (β = 0.16) appeared to influence %BMIp95. Longitudinal evidence broadly supported these findings. Results regarding cortical volume were inconsistent. Results supported causal effects of obesity on brain functioning and morphology. The present study highlights the importance of physical health for brain development and may inform interventions aimed at preventing or reducing pediatric obesity. RESEARCH HIGHLIGHTS: A continuous measure related to obesity, %BMIp95, has correlations with various measures of brain functioning and structure Behavioral genetic and longitudinal modeling suggest causal links from personality, psychopathology, and eating behavior to %BMIp95 Results also indicate directional links from %BMIp95 to eating behavior, cognition, cortical thickness, and cortical surface area Obesity may play a role for healthy brain development during childhood.

A - 48 Neuropsychiatric Symptom Severity Predicts Rate of Executive Function Decline

OBJECTIVE

Neuropsychiatric symptoms (NPS) are considered diagnostic and prognostic indicators of dementia and are attributable to neurodegenerative processes. NPS are distressing for patients and caregivers and are associated with accelerated functional decline, hospitalization, and institutionalization. Evaluation of NPS effects on disease course may reduce patient and caregiver distress and support development of personalized treatments. We examined whether baseline NPS predicted the rate of executive function (EF) decline among older adults with cognitive impairment.

METHOD

Older adults (n = 1155) with cognitive impairment and four years of data were selected from the National Alzheimer's Coordinating Center database v3-v3.2. Overall EF was estimated with a latent factor indicated by scores on Number Span Backward, Letter Fluency, and Trail Making-Part B. Strict temporal invariance was established. A curve of factors (CUFF) latent growth curve model was estimated to examine rate of change. Baseline NPS severity was entered as a predictor to examine its influence on the rate of change in EF over time.

RESULTS

The predicted CUFF model exhibited good fit (χ2[69] = 201.46, p < 0.001; CFI = 0.98, RMSEA = 0.04). EF significantly declined over four waves (slope = -0.53). NPS severity at baseline predicted decline in EF (β = 0.164, p = 0.001), such that those with greater NPS severity demonstrated a more rapid decrease in EF performance over time.

CONCLUSIONS

Increased NPS severity at baseline predicts more rapid decline in EF over four years. Findings highlight the prognostic value of NPS on cognitive decline and underscore the importance of targeting NPS at early disease stages. Future research will examine influence of individual NPS on rate of cognitive decline.

Testing the temporal precedence of family functioning and child psychopathology in the LONGSCAN sample

Family functioning may serve as protective or risk factors in the development of youth psychopathology. However, few studies have examined the potentially reciprocal relation between child psychopathology and family functioning. To fill this gap in the literature, this study tested for time-ordered associations between measures of family functioning (e.g., cohesion, conflict, and emotional expressiveness) and child psychopathology (e.g., total behavior problems, externalizing, and internalizing problems) using data from the Longitudinal Studies of Child Abuse and Neglect (LONGSCAN; N = 1143, 52.3% female, Nwaves = 5). We used a random-intercept cross-lagged panel model to identify whether child psychopathology preceded and predicted family functioning, the reverse, or both processes occurred simultaneously. At the between-person level, families who tended to have more cohesion, who lacked conflict, and who expressed their emotions had lower levels of child psychopathology. At the within-person level in childhood, we found minimal evidence for time-ordered associations. In adolescence, however, a clear pattern whereby early psychopathology consistently predicted subsequent family functioning emerged, and the reverse direction was rarely found. Results indicate a complex dynamic relation between the family unit and child that have important implications for developmental models that contextualize risk and resilience within the family unit.

Personality stability and change: A meta-analysis of longitudinal studies

Past research syntheses provided evidence that personality traits are both stable and changeable throughout the life span. However, early meta-analytic estimates were constrained by a relatively small universe of longitudinal studies, many of which tracked personality traits in small samples over moderate time periods using measures that were only loosely related to contemporary trait models such as the Big Five. Since then, hundreds of new studies have emerged allowing for more precise estimates of personality trait stability and change across the life span. Here, we updated and extended previous research syntheses on personality trait development by synthesizing novel longitudinal data on rank-order stability (total k = 189, total N = 178,503) and mean-level change (total k = 276, N = 242,542) from studies published after January 1, 2005. Consistent with earlier meta-analytic findings, the rank-order stability of personality traits increased significantly throughout early life before reaching a plateau in young adulthood. These increases in stability coincide with mean-level changes in the direction of greater maturity. In contrast to previous findings, we found little evidence for increasing rank-order stabilities after Age 25. Moreover, cumulative mean-level trait changes across the life span were slightly smaller than previously estimated. Emotional stability, however, increased consistently and more substantially across the life span than previously found. Moderator analyses indicated that narrow facet-level and maladaptive trait measures were less stable than broader domain and adaptive trait measures. Overall, the present findings draw a more precise picture of the life span development of personality traits and highlight important gaps in the personality development literature. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

Testing the factor structure and measurement invariance of the Temporal Experience of Pleasure Scale in adolescents across time, gender, and race/ethnicity

The Temporal Experience of Pleasure Scale (TEPS) is a self-report measure designed to assess anticipatory and consummatory pleasure, two facets of anhedonic predispositions. Despite its widespread use, the factor structure of the TEPS has yet to be tested in adolescents, who are at increased risk for psychopathology and undergoing rapid changes in reward-related processes. In response, the present study aimed to test the factor structure and measurement invariance of the TEPS across time, gender, and race/ethnicity in a diverse adolescent sample. Adolescents (N = 441; M_age = 14.98; 223 female) who identified as either Black (37%), Hispanic (37%), or White (26%), completed the TEPS at Baseline, 6-month, and 12-month follow-ups. Factor analyses were conducted to examine the factor structure of the TEPS, while configural, metric, scalar, and strict invariance were tested across time and demographics. Findings supported the two-factor structure of the TEPS, above and beyond other conceptualizations (e.g., 4-factor, bifactor), full longitudinal invariance, and partial invariance across gender and race/ethnicity. Examination of mean differences suggested no temporal, gender nor race/ethnic differences for anticipatory pleasure. For consummatory pleasure, no differences were found for gender, but results suggested higher levels over time and lower levels in Black adolescents. Our findings provide preliminary support for reliable cross-group interpretations of anticipatory and consummatory anhedonic predispositions as measured through the TEPS. Together, results provide support for the clinical utility of the TEPS for anhedonic-related psychopathology risk assessment in adolescence. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

Genetic and Environmental Factors of Non-Ability-Based Confidence

Non-ability-based confidence is confidence in one’s ability that is not calibrated to actual ability. Here, we examine what psychological factors are associated with possessing more or less confidence relative to one’s ability and to what extent genetic and environmental processes contribute to these links. Using data from the Texas Twin Project ( N = 1,588 participants, aged 7–15 years), we apply a latent variable residual approach to calculate non-ability-based confidence as self-rated confidence net of ability on standardized cognitive tests. Non-ability-based confidence was modestly heritable (9%–28%) and strongly positively correlated with the need for cognition, mastery goal orientation, grit, openness, and emotional stability. These correlations were partly mediated by genetic factors (57% of the association on average). This widespread pattern of associations between non-ability-based confidence and several other measures of thinking, feeling, and acting suggest that non-ability-based confidence can be conceptualized as a personality attribute.

Mental Health Contributors Among Transgender People in a Non-WEIRD Society: Evidence From China

Transgender people face numerous social hurdles and consequently report elevated rates of mental health problems. However, little research has examined whether established mental health findings generalize to experiences of transgender people outside of Western contexts. In an analysis of the 2017 Chinese Transgender Population General Survey ( N = 1,106), we examined how discrimination and environmental support in a school context related to mental health and self-harm among transgender people. We found that more frequent school discrimination was associated with worse mental health and increased self-harm. Further, perceived environmental support was associated with better mental health but was unrelated to self-harm. These relations did not differ based on whether people were “out” about being transgender at school or between men and women. These findings highlight nuance in the experiences of transgender people outside of Western contexts and hold implications for developing effective social interventions.

Adolescent Big Five personality and pubertal development: Pubertal hormone concentrations and self-reported pubertal status

In early adolescence, levels of conscientiousness and agreeableness have been found to temporarily decrease, with levels of neuroticism increasing, indicating a dip in personality maturation. It is unknown whether these changes are related to the process of puberty, a major developmental milestone with numerous changes for children. Here, we first replicated the dip in personality maturity in early adolescence (N = 2640, age range 8-18, 51% girls, 65% non-Hispanic white, 21% Hispanic/Latino, 10% African American, 9% other, roughly 33% of families received means-tested public assistance) and tested associations between the Big Five personality dimensions and pubertal development and timing across late childhood and adolescence (n = 1793). Pubertal development was measured using both hormonal assays (DHEA, testosterone, and progesterone) and self-reports of secondary sex characteristics. Of hormonal measures, only higher DHEA concentrations were associated with lower conscientiousness and openness. Nonparametric moderation analyses using LOSEM indicated Complex Age × Sex interactions involving all three hormones. Self-reported pubertal development was associated with lower extraversion, conscientiousness, agreeableness, and openness. More advanced pubertal timing was also related to lower levels of extraversion, conscientiousness, and agreeableness. All associations were small. As some evidence was found for small associations between pubertal development and lower levels of conscientiousness and agreeableness, a dip in personality maturation in these personality traits may be partly due to pubertal development in early adolescence. Overall, results did not indicate that pubertal development was the primary explanation of the maturity dip in adolescent personality. Many small influences likely accumulate to explain the dip in personality maturity in early adolescence. (PsycInfo Database Record (c) 2020 APA, all rights reserved).

Childhood growth in math and reading differentially predicts adolescent non-ability-based confidence: An examination in the SECCYD

Non-ability-based confidence is one of the most pervasive human psychological biases. It is a part of a family of confidence judgments, including overconfidence and metacognitive calibration accuracy, defined by a discrepancy between self-perception of ability and actual ability. Across many domains, most people exhibit some degree of miscalibration in their confidence. Some people may be overconfident and others are underconfident. Despite the prevalence of non-ability-based confidence, relatively little research has investigated how non-ability-based confidence develops and why some people are more or less confident than others despite sharing the same level of ability. We use a longitudinal dataset to explore the childhood predictors of adolescent non-ability-based confidence. Achievement growth in math and reading in childhood was modeled and used to predict adolescent non-ability-based confidence in math and reading. Results show that the initial level of achievement predicts lower non-ability-based confidence in math. On the other hand, a faster rate of achievement growth across childhood predicts greater non-ability-based confidence in reading. These results highlight how previous experiences inform people's self-perceptions over and above their true abilities. Discussion focuses on the factors that shape non-ability-based confidence over the lifespan and the limitations of the current findings.

Your Personality does not Care Whether you Believe it Can Change: Beliefs about Whether Personality can Change do not Predict Trait Change among Emerging Adults

Theorists have suggested that beliefs about whether personality can change might operate in a self–fulfilling fashion, leading to growth in personality traits across time. In the present two studies, we collected intensive longitudinal data from a total of 1339 emerging adults ( ns = 254 and 1085) and examined the extent to which both global beliefs that personality can change (e.g. ‘You can change even your most basic qualities’) and granular beliefs that the individual Big Five personality domains can change (e.g. ‘You can change how extraverted and enthusiastic you generally are’) predicted trait change across approximately 4 months. Results indicated that traits did change across time, yet beliefs that personality can change were almost completely unrelated to actual change in personality traits. Our findings suggest that personality development during emerging adulthood does not depend to any meaningful degree on whether or not individuals believe that their traits can change. © 2020 European Association of Personality Psychology

Personality Changes Predict Early Career Outcomes: Discovery and Replication in 12-Year Longitudinal Studies

In this research, we examined whether personality changes from adolescence to young adulthood predicted five early career outcomes: degree attainment, income, occupational prestige, career satisfaction, and job satisfaction. The study used two representative samples of Icelandic youth (Sample 1: n = 485, Sample 2: n = 1,290) and measured personality traits over 12 years (ages ~17 to 29 years). Results revealed that certain patterns of personality growth predicted career outcomes over and above adolescent trait levels and crystallized ability. Across both samples, the strongest effects were found for growth in emotional stability (income and career satisfaction), conscientiousness (career satisfaction), and extraversion (career satisfaction and job satisfaction). Initial trait levels also predicted career success, highlighting the long-term predictive power of personality. Overall, our findings show that personality has important effects on early career outcomes-both through stable trait levels and how people change over time. We discuss implications for public policy, for theoretical principles of personality development, and for young people making career decisions.

Change Goals Robustly Predict Trait Growth: A Mega-Analysis of a Dozen Intensive Longitudinal Studies Examining Volitional Change

Research suggests that change goals (desires to change personality traits) predict subsequent trait growth. In this article, we (re)analyzed all data our labs have collected as of May 2019 that included measures of change goals and repeated measures of personality traits (12 studies; total n = 2,238). Results indicated that change goals robustly predicted growth in all five traits. Effect sizes were largest for extraversion and emotional stability (people with high change goals were predicted to experience ∼0.16 SDs greater growth across 16 weeks than their peers with average goals) and smallest for agreeableness and openness (people with high change goals were predicted to experience ∼0.05 SDs greater growth across 16 weeks than their peers with average goals). Thus, our analyses reinforce that people change in ways that align with their desires across time.

Volitional Change in Adult Attachment: Can People Who Want to Become Less Anxious and Avoidant Move Closer towards Realizing those Goals?

People value relationships and want to relate to both friends and romantic partners in a secure and comfortable fashion. But can individuals move towards realizing this goal of their own volition? To address this question, across three studies with a combined total of more than 4000 participants, we developed and validated a new measure of people's desires to change their attachment anxiety and avoidance. In Study 1, we created the new, 16–item Change Goals—Experiences in Close Relationships measure. In Study 2, we replicated the Change Goals—Experiences in Close Relationships’ factor structure and demonstrated that it correlates in theoretically expected ways with criterion variables (e.g. people who were high in undesirable traits such as anxiety or avoidance generally wanted to change those traits; change goals were linked to dissatisfaction with relevant life domains). Finally, in Study 3, we conducted a 16–wave, weekly longitudinal study. Results indicated that goals to change attachment anxiety and avoidance predicted corresponding growth across time (e.g. people who wanted to become less anxious tended to experience declines in attachment anxiety across time). Thus, our research provides a new measure for studying changes in attachment and suggests people may be able to increase in attachment security per their own volition. © 2019 European Association of Personality Psychology

Genetic overlap between executive functions and BMI in childhood

BACKGROUND

Executive functions (EFs) comprise a group of cognitive processes that selectively control and regulate attention. Inverse relations have been reported between EFs and BMI. However, the mechanisms underlying this association are not well understood.

OBJECTIVES

We aimed to decompose the inverse relation between EFs and BMI into genetic and environmental components.

METHODS

We employed a cross-sectional analysis of data from 869 twins aged 7-15 y from the Texas Twin Project, who completed a neuropsychological test battery measuring 4 EFs (switching, inhibitory control, working memory, and updating); academic achievement (reading and mathematics); and general cognitive abilities (general intelligence/intelligence quotient; crystallized and fluid intelligence; and processing speed). Participants also had their height and weight measured.

RESULTS

After controlling for age, sex, and race/ethnicity, BMI was inversely associated with a general EF factor representing the capacity to control and regulate goal-oriented behaviors (r = -0.125; P = 0.01; Q = 0.04). This inverse BMI-EF association was due to a significant overlap in genetic factors contributing to each phenotype (genetic correlation, rA, = -0.15; P < 0.001). Shared genetic influences accounted for 80% of the phenotypic association.

CONCLUSIONS

Children with higher general EF have lower BMIs, and this association is primarily attributable to shared genetic influences on both phenotypes. The results emphasize that higher weight associates not only with physical sequelae, but also with important cognitive attributes. This work adds to a growing body of research suggesting there are sets of genetic variants common across physical health and cognitive functioning.

Kids becoming less alike: A behavioral genetic analysis of developmental increases in personality variance from childhood to adolescence

Recent work in personality development has indicated that the magnitude of individual differences in personality increases over child development. Do such patterns reflect the differentiation of individuals by genotype, an increasing influence of environmental factors, or some (interactive) combination of the two? Using a population-based sample of over 2,500 twins and multiples from the Texas Twin Project, we estimated age trends in the variances in self- and parent-reported measures of the Big Five personality traits between Ages 8 and 18 years. We then estimated age trends in the genetic and environmental components of variance in each measure. Individual differences in personality increased in magnitude from childhood through mid-adolescence. This pattern emerged using both children's self-reports and ratings provided by their parents, and was primarily attributable to increases in the magnitude of genetic influences. Most of the increasing genetic variance appeared nonadditive, pointing to the possibility that developmental processes tend to make genetically similar individuals disproportionately more alike in their personality traits over time. These findings could reflect increasing or accumulating effects of trait-by-trait interactions; person-by-environment transactions, whereby genetically similar people are disproportionally likely to experience similar environments; the activation of dominant genes across developmental transitions (e.g., puberty); or some combination of these three processes, among other factors. Theories of personality development will need to accommodate these descriptive findings, and longitudinal, genetically informed designs are needed to test some of the specific hypotheses springing from this study. (PsycINFO Database Record (c) 2019 APA, all rights reserved).

Genetic and Environmental Influences on Achievement Goal Orientations Shift with Age

Students engage in learning activities with different achievement goal orientations. Some students pursue learning for learning sake (i.e. mastery goal orientation), some are driven by gaining favorable judgement of their performance (i.e. performance approach goal orientation), and others focus on avoiding negative judgement (i.e. performance avoidance goal orientation). These goal orientations are linked with academic achievement, and troublingly, students report decreasing levels of goal orientations across the school years. However, little is known concerning the mechanisms that drive this decline. In a large (N = 891 twin pairs) cross-sectional genetically informative sample (age = 8 to 22 years), we found that older students reported lower goal orientations. Then, we identified shifts in the magnitude of genetic and environmental variance in each goal orientation. For example, variance in mastery goal orientation was primarily associated with environmental factors during the elementary school years. As students entered high school, genetic influences increased, replacing shared environmental influences. Finally, we situated these findings in the larger nomological network by testing associations with psychological constructs (e.g. personality and cognitive ability) and contextual variables (e.g. parents, schools, and peers). The development of academic motivation is complex with many interconnecting factors that appear to shift with age.

National Gross Domestic Product, Science Interest, and Science Achievement: A Direct Replication and Extension of the Tucker-Drob, Cheung, and Briley (2014) Study

We replicated the study by Tucker-Drob, Cheung, and Briley (2014), who found that the association between science interest and science knowledge depended on economic resources at the family, school, and national levels, using data from the 2006 Programme for International Student Assessment (PISA). In more economically prosperous families, schools, and nations, student interest was more strongly correlated with actual knowledge. Here, we investigated whether these results still held despite substantial changes to educational and economic systems over roughly a decade. Using similar data from PISA 2015 ( N = 537,170), we found largely consistent results. Students from more economically advantaged homes, schools, and nations exhibited a stronger link between interests and knowledge. However, these moderation effects were substantially reduced, and the main effect of science interest increased by nearly 25%, driven almost entirely by families of low socioeconomic status and nations with low gross domestic product. The interdependence of interests and resources is robust but perhaps weakening with educational progress.

Interpreting Behavior Genetic Models: Seven Developmental Processes to Understand

Behavior genetic findings figure in debates ranging from urgent public policy matters to perennial questions about the nature of human agency. Despite a common set of methodological tools, behavior genetic studies approach scientific questions with potentially divergent goals. Some studies may be interested in identifying a complete model of how individual differences come to be (e.g., identifying causal pathways among genotypes, environments, and phenotypes across development). Other studies place primary importance on developing models with predictive utility, in which case understanding of underlying causal processes is not necessarily required. Although certainly not mutually exclusive, these two goals often represent tradeoffs in terms of costs and benefits associated with various methodological approaches. In particular, given that most empirical behavior genetic research assumes that variance can be neatly decomposed into independent genetic and environmental components, violations of model assumptions have different consequences for interpretation, depending on the particular goals. Developmental behavior genetic theories postulate complex transactions between genetic variation and environmental experiences over time, meaning assumptions are routinely violated. Here, we consider two primary questions: (1) How might the simultaneous operation of several mechanisms of gene-environment (GE)-interplay affect behavioral genetic model estimates? (2) At what level of GE-interplay does the 'gloomy prospect' of unsystematic and non-replicable genetic associations with a phenotype become an unavoidable certainty?

Genetic and Environmental Associations Between Child Personality and Parenting

Parenting is often conceptualized in terms of its effects on offspring. However, children may also play an active role in influencing the parenting they receive. Simple correlations between parenting and child outcomes may be due to parent-to-child causation, child-to-parent causation, or some combination of the two. We use a multi-rater, genetically informative, large sample (n = 1411 twin sets) to gain traction on this issue as it relates to parental warmth and stress in the context of child Big Five personality. Considerable variance in parental warmth (27%) and stress (45%) was attributable to child genetic influences on parenting. Incorporating child Big Five personality into the model explained roughly half of this variance. This result is consistent with the hypothesis that parents mold their parenting in response to their child's personality. Residual heritability of parenting is likely due to child characteristics beyond the Big Five.

Behaviour Genetic Frameworks of Causal Reasoning for Personality Psychology

Identifying causal relations from correlational data is a fundamental challenge in personality psychology. In most cases, random assignment is not feasible, leaving observational studies as the primary methodological tool. Here, we document several techniques from behaviour genetics that attempt to demonstrate causality. Although no one method is conclusive at ruling out all possible confounds, combining techniques can triangulate on causal relations. Behaviour genetic tools leverage information gained by sampling pairs of individuals with assumed genetic and environmental relatedness or by measuring genetic variants in unrelated individuals. These designs can find evidence consistent with causality, while simultaneously providing strong controls against common confounds. We conclude by discussing several potential problems that may limit the utility of these techniques when applied to personality. Ultimately, genetically informative designs can aid in drawing causal conclusions from correlational studies. Copyright © 2018 European Association of Personality Psychology

Genetic and environmental influences on pubertal hormones in human hair across development

Puberty is a complex biopsychosocial process that can affect an array of psychiatric and medical disorders emerging in adolescence. Although the pubertal process is driven by neuroendocrine changes, few quantitative genetic studies have directly measured puberty-relevant hormones. Hair samples can now be assayed for accumulation of hormones over several months. In contrast to more conventional salivary measures, hair measures are not confounded by diurnal variation or hormonal reactivity. In an ethnically and socioeconomically diverse sample of 1286 child and adolescent twins and multiples from 672 unique families, we estimated genetic and environmental influences on hair concentrations of testosterone, DHEA, and progesterone across the period of 8-18 years of age. On average, male DHEA and testosterone were highly heritable, whereas female DHEA, progesterone, and puberty were largely influenced by environmental components. We identified sex-specific developmental windows of maximal heritability in each hormone. Peak heritability for DHEA occurred at approximately 10 years of age for males and females. Peak heritability for testosterone occurred at age 12.5 and 15.2 years for males and females, respectively. Peak heritability for male progesterone occurred at 11.2 years, while the heritability of female progesterone remained uniformly low. The identification of specific developmental windows when genetic signals for hormones are maximized has critical implications for well-informed models of hormone-behavior associations in childhood and adolescence.

Normative changes in interests from adolescence to adulthood: A meta-analysis of longitudinal studies

Vocational interests predict a variety of important outcomes and are among the most widely applied individual difference constructs in psychology and education. Despite over 90 years of research, little is known about the longitudinal development of interests. In this meta-analysis, the authors investigate normative changes in interests through adolescence and young adulthood. Effect sizes were aggregated from 49 longitudinal studies reporting mean-level changes in vocational interests, containing 98 total samples and 20,639 participants. Random effects meta-analytic regression models were used to assess age-related changes and gender differences across Holland's (1959, 1997) RIASEC categories and composite dimensions (people, things, data, and ideas). Results showed that mean-level interest scores generally increase with age, but effect sizes varied across interest categories and developmental periods. Adolescence was defined by two broad patterns of change: interest scores generally decreased during early adolescence, but then increased during late adolescence. During young adulthood, the most striking changes were found across the people and things orientations. Interests involving people tended to increase (artistic, social, and enterprising), whereas interests involving things either decreased (conventional) or remained constant (realistic and investigative). Gender differences associated with occupational stereotypes reached a lifetime peak during early adolescence, then tended to decrease in all subsequent age periods. Overall findings suggest there are normative changes in vocational interests from adolescence to adulthood, with important implications for developmental theories and the applied use of interests. (PsycINFO Database Record

A meta-analysis of longitudinal associations between substance use and interpersonal attachment security

Substance use has long been associated with close relationship distress. Although the direction of influence for this association has not been established, it has often been assumed that substance use is the causal agent and that close relationship distress is the effect. But research seeking to establish temporal precedence in this link has produced mixed findings. Further, theoretical models of substance use and close relationship processes present the plausibility of the inverse pathway-that insecure close relationships may serve as a vulnerability factor for the development of later substance problems. The current review applies an attachment-theoretical framework to the association between close social bonds and substance use and substance-related problems. Targeting longitudinal studies of attachment and substance use, we examined 665 effect sizes drawn from 34 samples (total N = 56,721) spanning time frames ranging from 1 month to 20 years (M = 3.8 years). Results revealed a significant prospective correlation between earlier attachment and later substance use (r = -.11, 95% CI [-.14, -0.08]). Further, cross-lagged coefficients were calculated which parsed auto-regressive effects, indicating that lower attachment security temporally preceded increases in substance use (r = -.05, 95% CI [-.06, -.04]). Analyses further indicated that the pathway from earlier attachment to later substance use was significantly stronger than that from earlier substance use to later attachment. Results also revealed several moderators of the attachment-substance use link. These findings suggest that insecure attachment may be a vulnerability factor for substance use, and indicate close relationship quality as a promising line of inquiry in research on substance use disorder risk. (PsycINFO Database Record

Genetic and Environmental Pathways Underlying Personality Traits and Perceived Stress: Concurrent and Longitudinal Twin Studies

The present study examined the genetic and environmental etiology underlying the Big Five personality traits and perceived stress, concurrently and longitudinally. In study 1, we used the twin sample from the National Longitudinal Study of Adolescent to Adult Health (Add Health IV) data. The results indicated that about 70% of the association between the Big Five personality traits and perceived stress was due to genetic influences. In study 2, we used the twin sample from the Midlife in the United States Survey (MIDUS I and II) to examine the genetic and environmental influences underlying the longitudinal relations between the Big Five personality traits and perceived stress. The results suggested that continuity in perceived stress was primarily accounted for by genetic influences, and changes in perceived stress were mainly due to nonshared environmental influences. The continuity in the association between the five personality traits and perceived stress was largely accounted for by genetic factors, and nonshared environmental factors made greater contributions to changes in the association between personality traits and perceived stress. Among the Big Five personality traits, the genetic components in conscientiousness and neuroticism made substantial contributions to the genetic link between personality traits and perceived stress across both studies.

Genetic and environmental influences on household financial distress

Heterogeneity of household financial outcomes emerges from various individual and environmental factors, including personality, cognitive ability, and socioeconomic status (SES), among others. Using a genetically informative data set, we decompose the variation in financial management behavior into genetic, shared environmental and non-shared environmental factors. We find that about half of the variation in financial distress is genetically influenced, and personality and cognitive ability are associated with financial distress through genetic and within-family pathways. Moreover, genetic influences of financial distress are highest at the extremes of SES, which in part can be explained by neuroticism and cognitive ability being more important predictors of financial distress at low and high levels of SES, respectively.

Hidden heritability due to heterogeneity across seven populations

Meta-analyses of genome-wide association studies (GWAS), which dominate genetic discovery are based on data from diverse historical time periods and populations. Genetic scores derived from GWAS explain only a fraction of the heritability estimates obtained from whole-genome studies on single populations, known as the ‘hidden heritability’ puzzle. Using seven sampling populations (N=35,062), we test whether hidden heritability is attributed to heterogeneity across sampling populations and time, showing that estimates are substantially smaller from across compared to within populations. We show that the hidden heritability varies substantially: from zero (height), to 20% for BMI, 37% for education, 40% for age at first birth and up to 75% for number of children. Simulations demonstrate that our results more likely reflect heterogeneity in phenotypic measurement or gene-environment interaction than genetic heterogeneity. These findings have substantial implications for genetic discovery, suggesting that large homogenous datasets are required for behavioural phenotypes and that gene-environment interaction may be a central challenge for genetic discovery.

Genetic influences on hormonal markers of chronic hypothalamic-pituitary-adrenal function in human hair

BACKGROUND

Cortisol is the primary output of the hypothalamic-pituitary-adrenal (HPA) axis and is central to the biological stress response, with wide-ranging effects on psychiatric health. Despite well-studied biological pathways of glucocorticoid function, little attention has been paid to the role of genetic variation. Conventional salivary, urinary and serum measures are strongly influenced by diurnal variation and transient reactivity. Recently developed technology can be used to measure cortisol accumulation over several months in hair, thus indexing chronic HPA function.

METHOD

In a socio-economically diverse sample of 1070 twins/multiples (ages 7.80-19.47 years) from the Texas Twin Project, we estimated effects of sex, age and socio-economic status (SES) on hair concentrations of cortisol and its inactive metabolite, cortisone, along with their interactions with genetic and environmental factors. This is the first genetic study of hair neuroendocrine concentrations and the largest twin study of neuroendocrine concentrations in any tissue type.

RESULTS

Glucocorticoid concentrations increased with age for females, but not males. Genetic factors accounted for approximately half of the variation in cortisol and cortisone. Shared environmental effects dissipated over adolescence. Higher SES was related to shallower increases in cortisol with age. SES was unrelated to cortisone, and did not significantly moderate genetic effects on either cortisol or cortisone.

CONCLUSIONS

Genetic factors account for sizable proportions of glucocorticoid variation across the entire age range examined, whereas shared environmental influences are modest, and only apparent at earlier ages. Chronic glucocorticoid output appears to be more consistently related to biological sex, age and genotype than to experiential factors that cluster within nuclear families.

Substance use prevention and treatment outcomes for emerging adults in non-college settings: A meta-analysis

Emerging adults have the highest prevalence rate of alcohol and drug use and represent a large proportion of treatment admissions in the United States. Those who do not attend college experience higher rates of use and may not have similar advantages as those attending college. A systematic review included studies investigating prevention and treatment outcomes among emerging adults in non-college settings. We included studies reporting an average age between 18 and 25 conducted outside of college settings. We extracted data for experimental effects (experimental group compared to control), and contrasted treatments with active and no intervention controls. We also examined several moderators. Fifty studies were meta-analyzed, including 32 prevention and 18 treatment studies. Overall, our experimental weighted mean effect size was d = .17 for both prevention and treatment studies. Comparisons across treatment types typically yielded nonsignificant results. Across prevention and treatment studies, smaller effects existed for studies delivering personalized feedback interventions. For treatment studies only, the percent of students included in the sample was a significant moderator. Overall effects were similar to current meta-analyses on college drinking. However, personalized feedback may be a less effective prevention strategy in non-college settings, and the field should prioritize increasing the effectiveness of treatments targeting non-college students. (PsycINFO Database Record

A behavioral genetic analysis of callous-unemotional traits and Big Five personality in adolescence

Callous-unemotional (CU) traits, such as lacking empathy and emotional insensitivity, predict the onset, severity, and persistence of antisocial behavior. CU traits are heritable, and genetic influences on CU traits contribute to antisocial behavior. This study examines genetic overlap between CU traits and general domains of personality. We measured CU traits using the Inventory of Callous-Unemotional Traits (ICU) and Big Five personality using the Big Five Inventory in a sample of adolescent twins from the Texas Twin Project. Genetic influences on the Big Five personality dimensions could account for the entirety of genetic influences on CU traits. Item Response Theory results indicate that the Inventory of Callous and Unemotional Traits is better at detecting clinically relevant personality variation at lower extremes of personality trait continua, particularly low agreeableness and low conscientiousness. The proximate biological mechanisms that mediate genetic liabilities for CU traits remain an open question. The results of the current study suggest that understanding the development of normal personality may inform understanding of the genetic underpinnings of callous and unemotional behavior.

Sensation seeking and impulsive traits as personality endophenotypes for antisocial behavior: Evidence from two independent samples

Sensation seeking and impulsivity are personality traits that are correlated with risk for antisocial behavior (ASB). This paper uses two independent samples of twins to (a) test the extent to which sensation seeking and impulsivity statistically mediate genetic influence on ASB, and (b) compare this to genetic influences accounted for by other personality traits. In Sample 1, delinquent behavior, as well as impulsivity, sensation seeking and Big Five personality traits, were measured in adolescent twins from the Texas Twin Project. In Sample 2, adult twins from the Australian Twin Registry responded to questionnaires that assessed individual differences in Eysenck's and Cloninger's personality dimensions, and a structured telephone interview that asked participants to retrospectively report DSM-defined symptoms of conduct disorder. Bivariate quantitative genetic models were used to identify genetic overlap between personality traits and ASB. Across both samples, novelty/sensation seeking and impulsive traits accounted for larger portions of genetic variance in ASB than other personality traits. We discuss whether sensation seeking and impulsive personality are causal endophenotypes for ASB, or merely index genetic liability for ASB.

Strong genetic overlap between executive functions and intelligence

Executive functions (EFs) are cognitive processes that control, monitor, and coordinate more basic cognitive processes. EFs play instrumental roles in models of complex reasoning, learning, and decision making, and individual differences in EFs have been consistently linked with individual differences in intelligence. By middle childhood, genetic factors account for a moderate proportion of the variance in intelligence, and these effects increase in magnitude through adolescence. Genetic influences on EFs are very high, even in middle childhood, but the extent to which these genetic influences overlap with those on intelligence is unclear. We examined genetic and environmental overlap between EFs and intelligence in a racially and socioeconomically diverse sample of 811 twins ages 7 to 15 years (M = 10.91, SD = 1.74) from the Texas Twin Project. A general EF factor representing variance common to inhibition, switching, working memory, and updating domains accounted for substantial proportions of variance in intelligence, primarily via a genetic pathway. General EF continued to have a strong, genetically mediated association with intelligence even after controlling for processing speed. Residual variation in general intelligence was influenced only by shared and nonshared environmental factors, and there remained no genetic variance in general intelligence that was unique of EF. Genetic variance independent of EF did remain, however, in a more specific perceptual reasoning ability. These results provide evidence that genetic influences on general intelligence are highly overlapping with those on EF. (PsycINFO Database Record

Gender and genetic contributions to weight identity among adolescents and young adults in the U.S

In this paper, we investigate the possibility that genetic variation contributes to self-perceived weight status among adolescents and young adults in the U.S. Using samples of identical and fraternal twins across four waves of the National Longitudinal Study of Adolescent to Adult Health (Add Health) study, we calculate heritability estimates for objective body mass index (BMI) that are in line with previous estimates. We also show that perceived weight status is heritable (h(2) ∼ 0.47) and most importantly that this trait continues to be heritable above and beyond objective BMI (h(2) ∼ 0.25). We then demonstrate significant sex differences in the heritability of weight identity across the four waves of the study, where h(2)women = 0.39, 0.35, 0.40, and 0.50 for each wave, respectively, and h(2)men = 0.10, 0.10, 0.23, and 0.03. These results call for a deeper consideration of both identity and gender in genetics research.

Genetically-mediated associations between measures of childhood character and academic achievement

Researchers and the general public have become increasingly intrigued by the roles that systematic tendencies toward thinking, feeling, and behaving might play in academic achievement. Some measures of constructs belonging to this group have been well studied in genetics and psychometrics, while much less is known about measures of other such constructs. The current study focuses on 7 character traits prominently featured in influential intervention-oriented and/or socialization theories of academic achievement: grit, intellectual curiosity, intellectual self-concept, mastery orientation, educational value, intelligence mindset, and test motivation. In a population-based sample of 811 school-aged twins and triplets from the Texas Twin Project, we tested (a) how each measure relates to indices of the Big Five personality traits, (b) how the measures relate to one another, (c) the extent to which each measure is associated with genetic and environmental influences and whether such influences operate through common dimensions of individual differences, and (d) the extent to which genetic and environmental factors mediate the relations between fluid intelligence, character measures, verbal knowledge, and academic achievement. We find moderate relations among the measures that can be captured by a highly heritable common dimension representing a mixture of Openness and Conscientiousness. Moreover, genetically influenced variance in the character measures is associated with multiple measures of verbal knowledge and academic achievement, even after controlling for fluid intelligence. In contrast, environmentally influenced variance in character is largely unrelated to knowledge and achievement outcomes. We propose that character measures popularly used in education may be best conceptualized as indexing facets of personality that are of particular relevance to academic achievement. (PsycINFO Database Record

Puberty, Socioeconomic Status, and Depression in Girls: Evidence for Gene × Environment Interactions

In the current study, we tested for Gene × Environment interactions in the association between pubertal timing and adolescent depression by examining how socioeconomic factors might moderate age at menarche's relation with depressive symptoms. Participants comprised 630 female twin and sibling pairs from the National Longitudinal Study of Adolescent Health. Consistent with previous studies, results showed that genetic predispositions toward later menarche were associated with fewer depressive symptoms and that genetic predispositions toward earlier menarche were associated with more depressive symptoms. However, this pattern was subtle and evident only in girls from higher socioeconomic backgrounds. Although girls from lower socioeconomic families showed the highest overall levels of depression, their symptoms appeared unrelated to timing of physical development through either a genetic or an environmental path.

Developmental changes in genetic and environmental influences on rule-breaking and aggression: age and pubertal development

BACKGROUND

Antisocial behavior (ASB) can be meaningfully divided into nonaggressive rule-breaking versus aggressive dimensions, which differ in developmental course and etiology. Previous research has found that genetic influences on rule-breaking, but not aggression, increase from late childhood to mid-adolescence. This study tested the extent to which the developmental increase in genetic influence on rule-breaking was associated with pubertal development compared to chronological age.

METHOD

Child and adolescent twins (n = 1,031), ranging in age from 8 to 20 years (M age = 13.5 years), were recruited from public schools as part of the Texas Twin Project. Participants reported on their pubertal development using the Pubertal Development Scale and on their involvement in ASB on items from the Child Behavior Checklist. Measurement invariance of ASB subtypes across age groups (≤12 years vs. >12 years old) was tested using confirmatory factor analyses. Quantitative genetic modeling was used to test whether the genetic and environmental influences on aggression and rule-breaking were moderated by age, pubertal status, or both.

RESULTS

Quantitative genetic modeling indicated that genetic influences specific to rule-breaking increased as a function of pubertal development controlling for age (a gene × puberty interaction), but did not vary as a function of age controlling for pubertal status. There were no developmental differences in the genetic etiology of aggression. Family-level environmental influences common to aggression and rule-breaking decreased with age, further contributing to the differentiation between these subtypes of ASB from childhood to adolescence.

CONCLUSIONS

Future research should discriminate between alternative possible mechanisms underlying gene × puberty interactions on rule-breaking forms of antisocial behavior, including possible effects of pubertal hormones on gene expression.

Nonparametric Estimates of Gene × Environment Interaction Using Local Structural Equation Modeling

Gene × environment (G × E) interaction studies test the hypothesis that the strength of genetic influence varies across environmental contexts. Existing latent variable methods for estimating G × E interactions in twin and family data specify parametric (typically linear) functions for the interaction effect. An improper functional form may obscure the underlying shape of the interaction effect and may lead to failures to detect a significant interaction. In this article, we introduce a novel approach to the behavior genetic toolkit, local structural equation modeling (LOSEM). LOSEM is a highly flexible nonparametric approach for estimating latent interaction effects across the range of a measured moderator. This approach opens up the ability to detect and visualize new forms of G × E interaction. We illustrate the approach by using LOSEM to estimate gene × socioeconomic status interactions for six cognitive phenotypes. Rather than continuously and monotonically varying effects as has been assumed in conventional parametric approaches, LOSEM indicated substantial nonlinear shifts in genetic variance for several phenotypes. The operating characteristics of LOSEM were interrogated through simulation studies where the functional form of the interaction effect was known. LOSEM provides a conservative estimate of G × E interaction with sufficient power to detect statistically significant G × E signal with moderate sample size. We offer recommendations for the application of LOSEM and provide scripts for implementing these biometric models in Mplus and in OpenMx under R.

Genes Unite Executive Functions in Childhood

Individual differences in children's executive functions (EFs) are relevant for a wide range of normal and atypical psychological outcomes across the life span, but the origins of variation in children's EFs are not well understood. We used data from a racially and socioeconomically diverse sample of 505 third- through eighth-grade twins and triplets from the Texas Twin Project to estimate genetic and environmental influences on a Common EF factor and on variance unique to four core EF domains: inhibition, switching, working memory, and updating. As has been previously demonstrated in young adults, the Common EF factor was 100% heritable, which indicates that correlations among the four EF domains are entirely attributable to shared genetic etiology. Nonshared environmental influences were evident for variance unique to individual domains. General EF may thus serve as an early life marker of genetic propensity for a range of functions and pathologies later in life.

Comparing the Developmental Genetics of Cognition and Personality over the Life Span

Empirical studies of cognitive ability and personality have tended to operate in isolation of one another. We suggest that returning to a unified approach to considering the development of individual differences in both cognition and personality can enrich our understanding of human development. We draw on previous meta-analyses of longitudinal, behavior genetic studies of cognition and personality across the life span, focusing particular attention on age trends in heritability and differential stability. Both cognition and personality are moderately heritable and exhibit large increases in stability with age; however, marked differences are evident. First, the heritability of cognition increases substantially with child age, while the heritability of personality decreases modestly with age. Second, increasing stability of cognition with age is overwhelmingly mediated by genetic factors, whereas increasing stability of personality with age is entirely mediated by environmental factors. Third, the maturational time-course of stability differs: Stability of cognition nears its asymptote by the end of the first decade of life, whereas stability of personality takes three decades to near its asymptote. We discuss how proximal gene-environment dynamics, developmental processes, broad social contexts, and evolutionary pressures may intersect to give rise to these divergent patterns.

Structure and correlates of cognitive aging in a narrow age cohort

Aging-related changes occur for multiple domains of cognitive functioning. An accumulating body of research indicates that, rather than representing statistically independent phenomena, aging-related cognitive changes are moderately to strongly correlated across domains. However, previous studies have typically been conducted in age-heterogeneous samples over longitudinal time lags of 6 or more years, and have failed to consider whether results are robust to a comprehensive set of controls. Capitalizing on 3-year longitudinal data from the Lothian Birth Cohort of 1936, we took a longitudinal narrow age cohort approach to examine cross-domain cognitive change interrelations from ages 70 to 73 years. We fit multivariate latent difference score models to factors representing visuospatial ability, processing speed, memory, and crystallized ability. Changes were moderately interrelated, with a general factor of change accounting for 47% of the variance in changes across domains. Change interrelations persisted at close to full strength after controlling for a comprehensive set of demographic, physical, and medical factors including educational attainment, childhood intelligence, physical function, APOE genotype, smoking status, diagnosis of hypertension, diagnosis of cardiovascular disease, and diagnosis of diabetes. Thus, the positive manifold of aging-related cognitive changes is highly robust in that it can be detected in a narrow age cohort followed over a relatively brief longitudinal period, and persists even after controlling for many potential confounders.

Gross domestic product, science interest, and science achievement: a person × nation interaction

Maximizing science achievement is a critical target of educational policy and has important implications for national and international economic and technological competitiveness. Previous research has identified both science interest and socioeconomic status (SES) as robust predictors of science achievement, but little research has examined their joint effects. In a data set drawn from approximately 400,000 high school students from 57 countries, we documented large Science Interest × SES and Science Interest × Per Capita Gross Domestic Product (GDP) interactions in the prediction of science achievement. Student interest in science is a substantially stronger predictor of science achievement in higher socioeconomic contexts and in higher-GDP nations. Our results are consistent with the hypothesis that in higher-opportunity contexts, motivational factors play larger roles in learning and achievement. They add to the growing body of evidence indicating that substantial cross-national differences in psychological effect sizes are not simply a logical possibility but, in many cases, an empirical reality.