Behaviour Genetic Frameworks of Causal Reasoning for Personality Psychology

Linking genetic foundations of sleep disturbances to personality traits: a study of mid-life twins

Risk of sleep disturbances depends on individuals' personality, and a large body of evidence indicates that individuals prone to neuroticism, impulsivity, and (low) extraversion are more likely to experience them. Origins of these associations are unclear, but common genetic background may play an important role. Participants included 405 twin pairs (mean age of 54 years; 59% female) from the National Survey of Midlife Development in the United States (MIDUS) who reported on their personality traits (broad and specific), as well as sleep disturbances (problems with falling asleep, staying asleep, waking early, and feeling unrested). Uni- and bivariate biometric decompositions evaluated contributions of genetic and environmental factors to associations between personality and poor sleep, as well as unique contributions from individual traits. Neuroticism, extraversion, conscientiousness, and aggressiveness were the strongest phenotypic predictors of poor sleep. Genetic sources of covariance were about twice as large as non-shared environmental sources, and only shared genetic background accounted for links between aggressiveness and poor sleep. Neuroticism and extraversion accounted for most of the genetic overlap between personality and sleep disturbances. The findings shed light on developmental antecedents of ties between personality and poor sleep, suggesting a larger role of common genetic background than idiosyncratic life experiences. The results also suggest that emotion-related traits play the most important role for poor sleep, compared to other personality traits, and may partially account for genetic associations with other traits.

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.

Personality and peer groups in adolescence: Reciprocal associations and shared genetic and environmental influences

OBJECTIVE

Peer groups represent a critical developmental context in adolescence, and there are many well-documented associations between personality and peer behavior at this age. However, the precise nature and direction of these associations are difficult to determine as youth both select into, and are influenced by, their peers.

METHOD

We thus examined the phenotypic, genetic, and environmental links between antisocial and prosocial peer characteristics and several personality traits from middle childhood to late adolescence (ages 11, 14, and 17 years) in a longitudinal twin sample (N = 3762) using teacher ratings of personality and self-reports of peer characteristics.

RESULTS

Less adaptive trait profiles (i.e., high negative emotionality, low conscientiousness, and low agreeableness) were associated with more antisocial and fewer prosocial peer characteristics across time. Associations between personality traits related to emotionality (negative emotionality and extraversion) and peer behavior were largely attributable to shared genetic influences, while associations between personality traits related to behavioral control (conscientiousness and agreeableness) and peer behavior were due to overlapping genetic and shared environmental influences.

CONCLUSIONS

Overall, results suggest a set of environmental presses that push youth toward both behavioral undercontrol and antisocial peer affiliations, making the identification of such influences and their relative importance a critical avenue of future work.

Do birds of a feather leave the nest together? The role of sibling personality similarity in the transition to adulthood

Empirical evidences on intragenerational transmission of life course have been demonstrated and that interpersonal similarity may moderate the effect. In particular, siblings who are more similar in their demographic characteristics are more likely to follow each other's life course transitions. Focusing on parental home-leaving and building upon the social influence processes and similarity-attraction effects, this study investigates whether the association between siblings' departures from the parental home increases when they are similar in the Big Five personality traits, like similarity in demographic traits. We use 28 waves of a longitudinal sample from "Understanding Society: The U.K. Household Longitudinal Study". The results of the multilevel discrete-time event-history analysis (N = 3,717 children) indicate that the association between leaving of a sibling and oneself was strengthened when they had a similar level of extraversion, particularly when they were both introverts. This implies that although introverted adolescents and emerging adults might take less initiative regarding social relationships and be more hesitant in their transition to adulthood, when a similarly introverted sibling makes such a transition, they are more inclined to do so. To conclude, the study uncovers the relationship between siblings' personality similarity and their resemblance in nest-leaving, which helps explain young adults' home-leaving decision in an era when delayed leaving is observed.

Unraveling the Relation Between Personality and Well-Being in a Genetically Informative Design

In the current study, common and unique genetic and environmental influences on personality and a broad range of well-being measures were investigated. Data on the Big Five, life satisfaction, quality of life, self-rated health, loneliness, and depression from 14,253 twins and their siblings (age M: 31.82, SD: 14.41, range 16–97) from the Netherlands Twin Register were used in multivariate extended twin models. The best-fitting theoretical model indicated that genetic variance in personality and well-being traits can be decomposed into effects due to one general, common factor ( Mdn: 60%, range 15%–89%), due to personality-specific ( Mdn: 2%, range 0%–78%) and well-being-specific ( Mdn: 12%, range 4%–35%) factors, and trait-specific effects ( Mdn: 18%, range 0%–65%). Significant amounts of non-additive genetic influences on the traits’ (co)variances were found, while no evidence was found for quantitative or qualitative sex differences. Taken together, our study paints a fine-grained, complex picture of common and unique genetic and environmental effects on personality and well-being. Implications for the interpretation of shared variance, inflated phenotypic correlations between traits and future gene finding studies are discussed.

That’s a Lot to Process! Pitfalls of Popular Path Models

Path models to test claims about mediation and moderation are a staple of psychology. But applied researchers may sometimes not understand the underlying causal inference problems and thus endorse conclusions that rest on unrealistic assumptions. In this article, we aim to provide a clear explanation for the limited conditions under which standard procedures for mediation and moderation analysis can succeed. We discuss why reversing arrows or comparing model fit indices cannot tell us which model is the right one and how tests of conditional independence can at least tell us where our model goes wrong. Causal modeling practices in psychology are far from optimal but may be kept alive by domain norms that demand every article makes some novel claim about processes and boundary conditions. We end with a vision for a different research culture in which causal inference is pursued in a much slower, more deliberate, and collaborative manner.

Two genetic analyses to elucidate causality between body mass index and personality

BACKGROUND/OBJECTIVES

Many personality traits correlate with BMI, but the existence and direction of causal links between them are unclear. If personality influences BMI, knowing this causal direction could inform weight management strategies. Knowing that BMI instead influences personality would contribute to a better understanding of the mechanisms of personality development and the possible psychological effects of weight change. We tested the existence and direction of causal links between BMI and personality.

SUBJECTS/METHODS

We employed two genetically informed methods. In Mendelian randomization, allele scores were calculated to summarize genetic propensity for the personality traits neuroticism, worry, and depressive affect and used to predict BMI in an independent sample (N = 3 541). Similarly, an allele score for BMI was used to predict eating-specific and domain-general phenotypic personality scores (PPSs; aggregate scores of personality traits weighted by BMI). In a direction of causation (DoC) analysis, twin data from five countries (N = 5424) were used to assess the fit of four alternative models: PPSs influencing BMI, BMI influencing PPSs, reciprocal causation, and no causation.

RESULTS

In Mendelian randomization, the allele score for BMI predicted domain-general (β = 0.05; 95% CI: 0.02, 0.08; P = 0.003) and eating-specific PPS (β = 0.06; 95% CI: 0.03, 0.09; P < 0.001). The allele score for worry also predicted BMI (β = -0.05; 95% CI: -0.08, -0.02; P < 0.001), while those for neuroticism and depressive affect did not (P ≥ 0.459). In DoC, BMI similarly predicted domain-general (β = 0.21; 95% CI:, 0.18, 0.24; P < 0.001) and eating-specific personality traits (β = 0.19; 95% CI:, 0.16, 0.22; P < 0.001), suggesting causality from BMI to personality traits. In exploratory analyses, links between BMI and domain-general personality traits appeared reciprocal for higher-weight individuals (BMI > ~25).

CONCLUSIONS

Although both genetic analyses suggested an influence of BMI on personality traits, it is not yet known if weight management interventions could influence personality. Personality traits may influence BMI in turn, but effects in this direction appeared weaker.

Conceptualizing and Studying Characteristics, Units, and Fits of Persons and Environments: A Coherent Synthesis

Based on a perspective on personality coherence as the extent to which personality-relevant characteristics are differentiated and integrated within a person in his or her environment, we propose a synthesis that builds on and harmonizes existing and partly conflicting theories, methodological approaches, and empirical findings. This understanding of personality coherence needs clear definitions of person and environment characteristics. We define traits as characteristics of the person, adaptations as characteristics of the person-in-contexts, and states as characteristics of the person-in-situations. Thus, our synthesis involves concepts of environments and person-environment units. Next, we provide testable criteria to differentiate characteristics of persons from characteristics of person-environment units and to identify dispositional traits for a narrow-sense perspective on personality coherence. We raise awareness of the importance of fit between (profiles of) person and environment characteristics for an understanding of the integrated uniqueness of persons in their environments. We outline implications of this broader perspective on personality coherence for personality development, self-regulation, social integration, well-being, and psychological interventions. Lastly, we conclude that the analysis of an individual’s uniqueness and personality differences requires information about how well-defined, well-differentiated, well-integrated, and well-operationalized person(ality) variables are actually expressed in, or interact and transact with, the individual environment.

Personality Psychology

Personality psychology, which seeks to study individual differences in thoughts, feelings, and behaviors that persist over time and place, has experienced a renaissance in the last few decades. It has also not been reviewed as a field in the Annual Review of Psychology since 2001. In this article, we seek to provide an update as well as a meta-organizational structure to the field. In particular, personality psychology has a prescribed set of four responsibilities that it implicitly or explicitly tackles as a field: (a) describing what personality is-i.e., what the units of analysis in the field are; (b) documenting how it develops; (c) explaining the processes of personality and why they affect functioning; and (d) providing a framework for understanding individuals and explaining their actions, feelings, and motivations. We review progress made over the last 20 years to address these four agendas and conclude by highlighting future directions and ongoing challenges to the field. Expected final online publication date for the Annual Review of Psychology, Volume 73 is January 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

Early Puberty Is Associated With Higher Academic Achievement in Boys and Girls and Partially Explains Academic Sex Differences

PURPOSE

On average, boys have lower academic achievement than girls. We investigated whether the timing of puberty is associated with academic achievement, and whether later puberty among boys contributes to the sex difference in academic achievement.

METHOD

Examination scores at age 16 were studied among 13,477 British twins participating in the population-based Twins Early Development Study. A pubertal development scale, a height-based proxy of growth spurt, and age at menarche were used as indicators of puberty. Associations between puberty, sex, and academic achievement were estimated in phenotypic mediation models and biometric twin models.

RESULTS

Earlier puberty was associated with higher academic achievement both in boys and girls. The exception was early age at menarche in girls, which associated with lower academic achievement. More than half of the sex differences in academic achievement could be linked to sex differences in pubertal development, but part of this association appeared to be rooted in prepubertal differences. The biometric twin modelling indicated that the association between puberty and academic achievement was due to shared genetic risk factors. Genetic influences on pubertal development accounted for 7%-8% of the phenotypic variation in academic achievement.

CONCLUSIONS

Pubertal maturation relates to the examination scores of boys and of girls. This can give genes related to pubertal maturation an influence on outcomes in education and beyond. Sex differences in pubertal maturation can explain parts of the sex difference in academic achievement. Grading students when they are immature may not accurately measure their academic potential.

Interpersonal Problems in Parents and Adolescent Borderline Personality Disorder Features

Research shows that parental personality pathology is associated with borderline personality disorder features and internalizing/externalizing symptoms in offspring. However, studies have been limited by DSM-IV-based assessments of parental personality pathology. The authors leveraged evidence that interpersonal problems described by the Interpersonal Circumplex align with Criterion A of the DSM-5 Alternative Model for Personality Disorders and therefore used a measure of interpersonal problems to capture parental personality pathology. The authors hypothesized that parental interpersonal problems would be associated with a latent variable of borderline features in adolescent offspring. They also examined whether this relation with offspring borderline features existed above and beyond relations with offspring internalizing/externalizing symptoms, age, and gender. The sample included 524 inpatient adolescents (M_age = 15.31, 62.4% female) and their parents (80.5% female). Parental interpersonal problems demonstrated unique relationships with adolescent borderline features and externalizing symptoms, but not internalizing symptoms. Implications of the results, limitations, and future directions are discussed.

Psychometric evaluation of Persian version of the balanced measure of psychological needs scale among university students

Aim

The purpose of the present study was to evaluate the reliability, validity and factor structure of the Persian version of the BMPN in Iranian university students.

Design

Cross‐sectional.

Methods

Study was conducted among Iranian medical sciences students from April to May 2020. A total of 660 students participated in the online self‐administrated questionnaire. Construct validity, convergent and divergent validity, and reliability of P‐BMPN were evaluated.

Results

The Exploratory factor analysis showed that the Persian version of the BMPN has 17 items with four factors: dissatisfaction, autonomy Satisfaction, relatedness satisfaction and competence satisfaction that explained 40.17% of the total variance. Based on confirmatory factor analysis, all goodness‐of‐fit indices confirmed the model fit.

Conclusion

These results suggest that the Persian version of the BMPN is a reliable and valid measure to assess satisfaction and dissatisfaction of the psychological needs in Iranian university students.

A developmental perspective on personality and psychopathology across the life span

Taking a developmental perspective, guided by core principles of developmental science and developmental psychopathology, is necessary to move the fields of personality science and psychopathology forward. Personality and psychopathology can be delineated using hierarchical models of individual differences, as evidenced by decades of converging evidence across community and psychiatric samples, countries and cultures, and ages and developmental periods. A large body of empirical research likewise documents associations between personality and various forms of psychopathology. Cross-sectional investigations of personality-psychopathology links in samples of adults now yield diminishing returns. Prospective, longitudinal investigations that assess personality, psychopathology, and their co-development across the life span are needed to determine their temporal ordering, capture dynamic associations over time and development, and elucidate causal origins and underlying mechanisms. We lay out a developmental framework that integrates across the developmental, personality, and psychopathology literatures in order to further understanding and guide future investigations of the nature of personality-psychopathology links.

Why Has Personality Psychology Played an Outsized Role in the Credibility Revolution?

Personality is not the most popular subfield of psychology. But, in one way or another, personality psychologists have played an outsized role in the ongoing "credibility revolution" in psychology. Not only have individual personality psychologists taken on visible roles in the movement, but our field's practices and norms have now become models for other fields to emulate (or, for those who share Baumeister's (2016, https://doi.org/10.1016/j.jesp.2016.02.003) skeptical view of the consequences of increasing rigor, a model for what to avoid). In this article we discuss some unique features of our field that may have placed us in an ideal position to be leaders in this movement. We do so from a subjective perspective, describing our impressions and opinions about possible explanations for personality psychology's disproportionate role in the credibility revolution. We also discuss some ways in which personality psychology remains less-than-optimal, and how we can address these flaws.

Genetic nurturing, missing heritability, and causal analysis in genetic statistics

Correlation between genotypes and phenotypes can be produced by genetic nurturing, namely the effect of parents’ genotypes on their offspring’s phenotypes through the parents’ phenotypes. Population subdivision and assortative mating can give rise to correlations between genotypes and phenotypes similar to those due to genetic nurturing. Variances and correlations may not reveal causal relationships in the presence of these complexities. We analyze mechanistic models of genetic nurturing, population subdivision, and assortative mating and compare these with results obtained within the framework of modern causal analysis. Our results clarify statistical signals emanating from correlations between nontransmitted alleles and offspring phenotypes and reveal difficulties with standard linear models in the interpretation of heritability, in particular, the concept of missing heritability.

Genetic nurturing, the effect of parents’ genotypes on offspring phenotypes through parental phenotypic transmission, can be modeled in terms of gene–culture interactions. This paper first uses a simple one-locus, two-phenotype gene–culture cotransmission model to compute the effect of genetic nurturing in terms of regression of children’s phenotypes on transmitted and nontransmitted alleles. With genetic nurturing, interpreting heritability and hence the meaning of “missing heritability” becomes problematic. Other factors, for example, population subdivision and assortative mating, generate similar signals to those of genetic nurturing, namely, correlation between parents’ nontransmitted alleles and children’s phenotypes. Corrections must be made for these to isolate the signal of genetic nurturing. Finally, a unified causal framework is constructed for genetic nurturing, population subdivision, and assortative mating. Causal and noncausal paths from transmitted and nontransmitted alleles to children’s phenotypes are identified and investigated in the presence of genetic nurturing, population subdivision, and assortative mating. Using causal analysis, assumptions made in inferring direct and indirect effects are then clarified and evaluated in a broader causal context.

The Taboo Against Explicit Causal Inference in Nonexperimental Psychology

Causal inference is a central goal of research. However, most psychologists refrain from explicitly addressing causal research questions and avoid drawing causal inference on the basis of nonexperimental evidence. We argue that this taboo against causal inference in nonexperimental psychology impairs study design and data analysis, holds back cumulative research, leads to a disconnect between original findings and how they are interpreted in subsequent work, and limits the relevance of nonexperimental psychology for policymaking. At the same time, the taboo does not prevent researchers from interpreting findings as causal effects—the inference is simply made implicitly, and assumptions remain unarticulated. Thus, we recommend that nonexperimental psychologists begin to talk openly about causal assumptions and causal effects. Only then can researchers take advantage of recent methodological advances in causal reasoning and analysis and develop a solid understanding of the underlying causal mechanisms that can inform future research, theory, and policymakers.

Toward an Integrative Model of Sources of Personality Stability and Change

There is now compelling evidence that people’s typical patterns of thinking, feeling, striving, and behaving are both consistent and malleable. Therefore, researchers have begun to examine the distinct sources of personality stability and change. In this article, we discuss traditional classifications of sources, review key findings, and highlight limitations and open questions in research on personality stability and change. We conclude by describing an integrative model and by outlining important directions for future research.

Longitudinal Experience–Wide Association Studies—A Framework for Studying Personality Change

The importance of personality for predicting life outcomes in the domains of love, work, and health is well established, as is evidence that personality traits, while relatively stable, can change. However, little is known about the sources and processes that drive changes in personality traits and how such changes might impact important life outcomes. In this paper, we make the case that the research paradigms and methodological approaches commonly used in personality psychology need to be revised to advance our understanding of the sources and processes of personality change. We propose Longitudinal Experience–Wide Association Studies as a framework for studying personality change that can address the limitations of current methods, and we discuss strategies for overcoming some of the challenges associated with Longitudinal Experience–Wide Association Studies. © 2020 European Association of Personality Psychology

Gene-environment interactions between HPA-axis genes and childhood maltreatment in depression: a systematic review

OBJECTIVE

Gene-environment (GxE) interactions may comprise an important part of the aetiology of depression, and childhood maltreatment (CM), a significant stressor, has consistently been linked to depression. Hence, in this systematic review, we aimed to investigate the interaction between hypothalamus-pituitary-adrenal axis (HPA-axis) genes and CM in depression.

METHODS

We conducted a literature search using the Pubmed, Embase, and PsychINFO databases in adherence with the Preferred Reporting Items for Systematic reviews and Meta-Analyses guidelines. We included studies investigating GxE interactions between HPA-axis genes [Angiotensin Converting Enzyme (ACE), Arginine Vasopressin (AVP), Corticotrophin Releasing Hormone (CRH), Corticotrophin Releasing Hormone Receptor 1 (CRHR1), Corticotrophin Releasing Hormone Receptor 2 (CRHR2), FK506 binding protein (FKBP5), Nuclear Receptor subfamily 3 group C member 1 (NR3C1), Nuclear Receptor subfamily 3 group C member 2 (NR3C2)] and CM in depression.

RESULTS

The literature search identified 159 potentially relevant studies. Following screening, 138 of these were excluded. Thus, 21 studies, investigating a total of 51 single nucleotide polymorphisms, were included in the final study. The most prevalent genes in the current study were CRHR1 and FKBP5. Significant GxE interactions were reported in seven of eight studies for CRHR1:rs110402 and CM, and in five of eight studies for FKBP5:rs1360780 and CM. In summary, our results suggest possible GxE interactions between CRHR1, FKBP5, NR3C1, and NR3C2 and CM, respectively. For the remaining genes, no relevant literature emerged.

CONCLUSIONS

We find that genetic variation in four HPA-axis genes may influence the effects of CM in depression.

Gene-environment interactions between HPA-axis genes and stressful life events in depression: a systematic review

OBJECTIVE

Depression is a disorder caused by genetics and environmental factors. The aim of this study was to perform a review investigating the interaction between genetic variations located in genes involved in hypothalamus-pituitary-adrenal axis (HPA-axis) and stressful life events (SLEs) in depression.

METHODS

In this systematic review, we selected articles investigating the interaction between genes involved in the HPA-axis, such as Arginine Vasopressin (AVP), Angiotensin Converting Enzyme (ACE), Corticotrophin Releasing Hormone (CRH), Corticotrophin Releasing Hormone Receptor 1 (CRHR1), Corticotrophin Releasing Hormone Receptor 2 (CRHR2), FK506 binding protein (FKBP5), Nuclear Receptor subfamily 3 group C member 1 (NR3C1), Nuclear Receptor subfamily 3 group C member 2 (NR3C2), and SLE. The literature search was conducted using the Pubmed, Embase, and PsychINFO databases in adherence with the PRISMA guidelines.

RESULTS

The search yielded 48 potentially relevant studies, of which 40 were excluded following screening. Eight studies were included in the final review. A total of 97 single nucleotide polymorphisms (SNPs) were examined in the eight included studies. The most prevalent gene was FKBP5, and the best studied polymorphism was FKBP5:rs1360780. Two of the five studies reported significant gene-environment (G × E) interactions between rs1360780 and SLE. Overall, four studies reported significant G × E interactions between FKBP5, CRH, or CRHR1 and SLE, respectively. No significant G × E interactions were found for the remaining genes.

CONCLUSIONS

Our results suggest that genetic variation in three genes in the HPA-axis possibly moderate the effects of SLEs in depression.

Explaining the association between anxiety disorders and alcohol use disorder: A twin study

BACKGROUND

It is unknown whether social anxiety disorder (SAD) has a unique association with alcohol use disorder (AUD) over and beyond that of other anxiety disorders, how the associations develop over time, and whether the associations are likely to be causal.

METHODS

Diagnoses of AUD, SAD, generalized anxiety disorder, panic disorder, agoraphobia, and specific phobias were assessed twice using the Composite International Diagnostic Interview among 2,801 adult Norwegian twins. The data were analyzed using logistic regression analyses and multivariate biometric structural equation modeling.

RESULTS

SAD had the strongest association with AUD, and SAD predicted AUD over and above the effect of other anxiety disorders. In addition, SAD was prospectively associated with AUD, whereas other anxiety disorders were not. AUD was associated with a slightly elevated risk of later anxiety disorders other than SAD. Biometric modeling favored a model where SAD influenced AUD compared to models where the relationship was reversed or due to correlated risk factors. Positive associations between AUD and other anxiety disorders were fully explained by shared genetic risk factors.

CONCLUSIONS

Unlike other anxiety disorders, SAD plausibly has a direct effect on AUD. Interventions aimed at prevention or treatment of SAD may have an additional beneficial effect of preventing AUD, whereas interventions aimed at other anxiety disorders are unlikely to have a similar sequential effect on AUD.

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?

Unravelling Quasi–Causal Environmental Effects via Phenotypic and Genetically Informed Multi–Rater Models: The Case of Differential Parenting and Authoritarianism

This study investigated the association between different experiences of parenting and individual right–wing authoritarianism (RWA) using twin family data comprising self– and informant reports. We applied a design that allowed us to examine whether the link between retrospective assessments of parenting and current RWA is effectively environmental or whether the association is attributable to genetic influences. We hypothesized that an authoritarian parenting style (low responsiveness and high demandingness) provided by the parents is associated with higher offspring's RWA, and that this association is similar for both twin siblings as a function of their genetic relatedness and shared familial experiences—that is, genotype–environment correlation. A sample of 875 twins as well as 319 mothers and 268 fathers completed a questionnaire on twins’ parental environment and their own authoritarian attitudes. Additionally, 1322 well–informed peers assessed twins’ RWA. Applying structural equation modelling, we found twins’ experiences of parental responsiveness and demandingness to be positively associated with self–reported and peer–reported RWA. The correlation between responsiveness and RWA was similar for both twins due to their genetic similarity, whereas twin differences in demandingness were positively associated with twin differences in RWA, indicating quasi–causal environmental effects. Implications for the interdependence between parenting and RWA are discussed. Copyright © 2018 European Association of Personality Psychology