Behavioral Genetic Analyses Research Articles

Personality and coping with professional demands: A behavioral genetics analysis.

Work-related mental health problems lead to individual ill-being but also absenteeism and early retirement from work. As such, it is desirable to diagnose strain and coping deficits before mental or physical symptoms occur in order to provide interventions early. Work engagement, resistance to stress, and occupational attitude toward life are three facets of coping with professional demands that are related to psychological health (Kieschke & Schaarschmidt, 2003). Personality, defined as characteristic patterns of thoughts, feelings, and behaviors over time and across situations, is also associated with health and well-being. To understand who becomes ill and why and to provide adequate interventions, we investigated the relations between personality and coping with professional demands, as well as the etiological basis of this relation. Personality and coping with professional demands (work engagement, resistance to stress, and occupational attitude toward life) were assessed in a sample of 302 monozygotic and dizygotic adult twin pairs. Correlations between personality and coping with professional demands were moderate (r range: -0.61 to 0.37). All scales except occupational attitude toward life showed significant heritabilities. Genetic and environmental influences on coping with professional demands were largely independent of genetic and environmental effects on personality. These findings suggest that interventions should focus on work engagement, resistance to stress, and occupational attitude toward life without specific considering of personality.

On the relationship of past to future involvement in crime and delinquency: A behavior genetic analysis

PurposeCriminologists have devoted much attention to identifying the factors that drive stability in antisocial behavior. This body of research has, however, overlooked the contributions of behavior genetic research. This study sought to blend behavior genetics with the different perspectives used by criminologists to explain stability. MethodsEmploying a behavioral genetic research design, the current study analyzed the correlation between adolescent and adulthood crime (a 13year time span was covered between the two time points) among a sample of sibling pairs drawn from the National Longitudinal Study of Adolescent Health (Add Health). ResultsThe findings revealed that genetic factors accounted for nearly all of the stability in offending behavior from adolescence to adulthood. Environmental factors (particularly, of the nonshared variety) accounted for the majority of the changes in offending. ConclusionsThe implications of these results for criminological research and theory are discussed.

A Behavioral-Genetic Study of Alexithymia and its Relationships with Trait Emotional Intelligence

The present study is the first to examine relationships between alexithymia and trait emotional intelligence (trait El or trait emotional self-efficacy) at the phenotypic, genetic, and environmental levels. The study was also conducted to resolve inconsistencies in previous twin studies that have provided estimates of the extent to which genetic and environmental factors contribute to individual differences in alexithymia. Participants were 216 monozygotic and 45 dizygotic same-sex twin pairs who completed the Toronto Alexithymia Scale-20. In a pilot study, a sub-sample of 118 MZ and 27 DZ pairs also completed the Trait Emotional Intelligence Questionnaire. Results demonstrated that a combination of genetic and non-shared environmental influences contribute to individual differences in alexithymia. As expected, alexithymia and trait El were negatively correlated at the phenotypic level. Bivariate behavioral genetic analyses showed that that all but one of these correlations was primarily attributable to correlated genetic factors and secondarily to correlated non-shared environmental factors.

Genetically influenced change in sensation seeking drives the rise of delinquent behavior during adolescence.

Sensation seeking is associated with an increased propensity for delinquency, and emerging research on personality change suggests that mean levels of sensation seeking increase substantially from childhood to adolescence. The current study tested whether individual differences in the rate of change of sensation seeking predicted within-person change in delinquent behavior and whether genetically influenced differences in rate of personality change accounted for this association. Sensation seeking and delinquent behavior were assessed biennially between ages 10-11 and 16-17 in a nationally representative sample of 7675 youths from the National Longitudinal Study of Youth: Children and Young Adults (CNLSY). Analyses using latent growth curve modeling found that within-person change in sensation seeking was significantly and positively correlated with within-person change in delinquency from childhood to adolescence. Furthermore, behavioral genetic analyses of a subset of 2562 sibling pairs indicated that there were substantial genetic influences on both initial levels of sensation seeking and change in sensation seeking during early adolescence, with over 80% of individual differences in change due to genetic factors. Finally, these genetically driven increases in sensation seeking were most important for predicting increases in delinquency, whereas environmental paths between sensation seeking and delinquency were not significant. These results suggest that developmental changes in delinquent behaviors during adolescence are driven by a genetically governed process of personality change.

Pairing dynamics and the origin of species

Whether sexual selection alone can drive the evolution of assortative mating in the presence of gene flow is a long-standing question in evolutionary biology. Here, we report a role for pairing dynamics of individuals when mate choice is mutual, which is sufficient for the evolution of assortative mating by sexual selection alone in the presence of gene flow. Through behavioural observation, individual-based simulation and population genetic analysis, we evaluate the pairing dynamics of coral reef fish in the genus Hypoplectrus (Serranidae), and the role these dynamics can play for the evolution of assortative mating. When mate choice is mutual and the stability of mating pairs is critical for reproductive success, the evolution of assortative mating in the presence of gene flow is not only possible, but is also a robust evolutionary outcome.

Genetic influences on core self-evaluations, job satisfaction, and work stress: A behavioral genetics mediated model

In this study we investigated the mediated influence of core self-evaluations (CSE) on employee health problems via job satisfaction and work stress, and the degree to which genetic factors explain these mediated relationships. Based on data obtained from a sample of 594 Swedish twins (114 monozygotic twin pairs and 183 dizygotic twin pairs), conventional path analysis results supported the mediated effects of CSE on employee health via job satisfaction and work stress, after controlling for conscientiousness and extraversion. Behavioral genetic analyses showed significant heritability of all four variables. Moreover, we found that the mediated relationships via job satisfaction and work stress are explained by genetic factors, such that the genetic source of job satisfaction and work stress mediates the genetic influence of CSE on health problems. These results highlight the role played by genetic factors in better understanding the relationships between CSE, work attitudes, and health outcomes.

Is sensory over‐responsivity distinguishable from childhood behavior problems? A phenotypic and genetic analysis

Although impaired sensory processing accompanies various clinical conditions, the question of its status as an independent disorder remains open. Our goal was to delineate the comorbidity (or lack thereof) between childhood psychopathology and sensory over-responsivity (SOR) in middle childhood using phenotypic and behavior-genetic analyses. Participants (N = 970) were drawn from the Wisconsin Twin Project, a population-based sample of twins and their families. Mothers completed a sensory responsivity checklist when their offspring were on average 7 years old, followed by a diagnostic interview (Diagnostic Interview Schedule for Children; DISC) within 6-12 months. We examined the incidence of DISC diagnoses - attention deficit hyperactivity disorder, conduct disorder, oppositional defiant disorder, agoraphobia, general anxiety, obsessive-compulsive disorder, panic disorder, separation anxiety, social phobia, specific phobia, depression, enuresis, trichtollomaniatics, selective mutism, and pica - among children with SOR, and vice versa. Children with autism or pervasive developmental disorders were excluded from the present study. In addition, we examined parent-reported physical health diagnoses among nondiagnosed children and three groups of children with SOR and/or DISC diagnoses. Biometric models explored common underlying genetic and environmental influences on symptoms of SOR and psychopathology. A majority of individuals who screened positive for SOR did not qualify for a DISC diagnosis (58.2%), and vice versa (68.3%). Children who screened positive for SOR only and typical children had similar rates of physical health problems. Turning to a dimensional approach, multivariate twin models demonstrated that modest covariation between SOR and DISC symptoms could be entirely accounted for by common underlying genetic effects. Our results suggest that SOR occurs independently of recognized childhood psychiatric diagnoses but is also a relatively frequent comorbid condition with recognized diagnoses. Genetic sources of this comorbidity are implicated.

Behavioral and molecular genetics of dissociation: The role of the serotonin transporter gene promoter polymorphism (5‐HTTLPR)

We evaluated the role of the serotonin transporter gene promoter polymorphism (5-HTTLPR) in the etiology of dissociation. Adult twin pairs (N = 184 pairs; mean age 33.0 years, SD = 10.8) completed measures for dissociation and trauma. The DNA samples were genotyped for 5-HTTLPR adjusted for rs25531 alleles. Behavioral genetic analyses showed that genetic factors explained 45% of the variance in dissociative symptoms, while 55% of the variance was explained by unique environment and measurement error. Participants with the SS genotype of 5-HTTLPR reported more dissociative symptoms compared to participants with the other genotypes (p = .02), and they showed more pathological dissociative symptoms than the other participants (p = .04) when they reported more depressive symptoms and when they had experienced trauma.

Beyond the Big Five: The Dark Triad and the Supernumerary Personality Inventory

The Dark Triad of personality, comprising Machiavellianism, narcissism, and psychopathy, was investigated in relation to the Supernumerary Personality Inventory (SPI) traits, because both sets of variables are predominantly distinct from the Big Five model of personality. Correlational and principal factor analyses were conducted to assess the relations between the Dark Triad and SPI traits. Multivariate behavioral genetic model-fitting analyses were also conducted to determine the correlated genetic and/or environmental underpinnings of the observed phenotypic correlations. Participants were 358 monozygotic and 98 same-sex dizygotic adult twin pairs from North America. As predicted, results revealed significant correlations between the Dark Triad and most SPI traits, and these correlations were primarily attributable to common genetic and non-shared environmental factors, except in the case of Machiavellianism, where shared environmental effects emerged. Three correlated factors were extracted during joint factor analysis of the Dark Triad and SPI traits, as well as a heritable general factor of personality - results that clarified the structure of the Dark Triad construct. It is concluded that the Dark Triad represents an exploitative and antisocial construct that extends beyond the Big Five model and shares a theoretical space with the SPI traits.

Separation of performance-approach and performance-avoidance achievement goals: A broader analysis.

In the literature on achievement goals, performance-approach goals (striving to do better than others) and performance-avoidance goals (striving to avoid doing worse than others) tend to exhibit a moderate to high correlation, raising questions about whether the 2 goals represent distinct constructs. In the current article, we sought to examine the separability of these 2 goals using a broad factor-analytic approach that attended to issues that have been overlooked or underexamined in prior research. Five studies provided strong evidence for the separation of these 2 goal constructs: Separation was observed not only with exploratory factor analysis across different age groups and countries (Studies 1a and 1b) but also with change analysis (Study 2), ipsative factor analysis (Study 3), within-person analysis (Study 4), and behavioral genetics analysis (Study 5). We conclude by discussing the implications of the present research for the achievement goal literature, as well as the psychological literature in general

Child and adolescent conduct disorder substantially shares genetic influences with three socioemotional dispositions.

In a representative sample of twin children and adolescents, we tested the hypothesis that a substantial proportion of the genetic and environmental influences underlying conduct disorder (CD) are shared with three socioemotional dispositions: Prosociality, Negative Emotionality, and Daring. Caretaker ratings of each dispositional dimension were uniquely associated with a latent CD dimension that included both caretaker- and youth-reports of CD as indicators. Behavior genetic analyses indicated that moderate-to-high additive genetic and moderate nonshared environmental influences underlie all three dispositions and CD, with modest shared environmental influences on Prosociality. Forty percent of the additive genetic influences and all of the nonshared environmental influences on the latent CD dimension were shared in common with the three socioemotional dispositions. The finding that CD shares a substantial proportion of its genetic influences with three distinct socioemotional dispositions suggests new perspectives on the heterogeneous etiology of CD and new approaches to exploring its specific etiological mechanisms.

Social Science Methods for Twins Data: Integrating Causality, Endowments, and Heritability

Twins have been extensively used in economics, sociology, and behavioral genetics to investigate the role of genetic endowments on a broad range of social, demographic, and economic outcomes. However, the focus in these literatures has been distinct: The economic literature has been primarily concerned with the need to control for unobserved endowments—including as an important subset, genetic endowments—in analyses that attempt to establish the impact of one variable, often schooling, on a variety of economic, demographic, and health outcomes. Behavioral genetic analyses have mostly been concerned with decomposing the variation in the outcomes of interest into genetic, shared environmental, and non-shared environmental components, with recent multivariate analyses investigating the contributions of genes and the environment to the correlation and causation between variables. Despite the fact that twins studies and the recognition of the role of endowments are central to both of these literatures, they have mostly evolved independently. In this paper, we develop formally the relationship between the economic and behavioral genetic approaches to the analyses of twins, and we develop an integrative approach that combines the identification of causal effects, which dominates the economic literature, with the decomposition of variances and covariances into genetic and environmental factors that are the primary goal of behavioral genetic approaches. We apply this integrative ACE-β approach to an illustrative investigation of the impact of schooling on several demographic outcomes such as fertility and nuptiality and health.

Developmental trajectories in toddlers' self-restraint predict individual differences in executive functions 14 years later: a behavioral genetic analysis.

We examined whether self-restraint in early childhood predicted individual differences in 3 executive functions (EFs; inhibiting prepotent responses, updating working memory, and shifting task sets) in late adolescence in a sample of approximately 950 twins. At ages 14, 20, 24, and 36 months, the children were shown an attractive toy and told not to touch it for 30 s. Latency to touch the toy increased with age, and latent class growth modeling distinguished 2 groups of children that differed in their latencies to touch the toy at all 4 time points. Using confirmatory factor analysis, we decomposed the 3 EFs (measured with latent variables at age 17 years) into a Common EF factor (isomorphic to response inhibition ability) and 2 factors specific to updating and shifting. Less-restrained children had significantly lower scores on the Common EF factor, equivalent scores on the Updating-Specific factor, and higher scores on the Shifting-Specific factor than did the more-restrained children. The less-restrained group also had lower IQ scores, but this effect was entirely mediated by the EF components. Twin models indicated that the associations were primarily genetic in origin for the Common EF variable but split between genetics and nonshared environment for the Shifting-Specific variable. These results suggest a biological relation between individual differences in self-restraint and EFs, one that begins early in life and persists into late adolescence.

Learning and the Value of Debate

I remember the dismay that I experienced as I encountered the level of contentiousness that seemed to characterize my doctoral classes. It was unnerving to discover that most of my fellow students were given to fairly intense debate over virtually every topic that we studied. Why?, I wondered. I slowly (and somewhat painfully) learned the benefit of debate in learning, especially in the sciences of the mind. Debate sharpens the focus and forces one to clarify his or her position. Recently, I stumbled on a reference to the course taught by cognitive scientist Stevan Harnad at the University of Southampton. The course is called Current Debates in Psychology (Harnad, n.d.). Basically, the course addresses controversial topics, which serve as the basis for the lectures and discussion that take place during the semester. The following six topics are selected from Harnad's 17-topic module in order to support the idea that psychology and its related content areas provide a platform for controversy at its best: * "Shrinks and Cranks." Do therapies-both psychic and somatic-work? What counts as evidence for and against? * "The Devil Made Me Do It." The dark sides of human nature: rape, incest, violence. Does sociobiology explain them? Is it all our evolutionary heritage? * "Me and My Selfish Genes." Is it all about getting power, property, and progeny? * "Or Do We Each Have Minds After All?" The critiques of sociobiology and behavior genetic analysis: psychological, statistical, biologic. * "When Science Tampers With Feelings." Intelligence testing, electroshock therapy, animal experiments: Science and human values. * "Consciousness of Consciousness." Do animals know others have minds? Do children? How can you tell? What is it for? (Harnad, n.d., paras. 5, 7-10, 20) The reader may wish to check out the entire list at http://users.ecs.soton.ac.uk/harnad/ debates.html (Harnad, n.d.), but as I reviewed the list, I could not help thinking of other debates that exist, and I wondered just how long the list could be if it were allowed to approach some degree of completeness. We could take the topics published over the years in Ethical Human Psychology and Psychiatry (EHPP) and use them to expand the list. As it happened, when I first reviewed Harnad's list, I was also composing this editorial, and thus the connection was drawn. Borrowing Harnad's style, I have noted in the following discussion several additional controversial topics that this issue of EHPP explores. Consider the various controversies that exist within the subjects covered in this issue of EHPP: the mental health of soldiers, the use of antidepressants, confrontation psychotherapy, epilepsy and the media, gifts to therapists, autism, and mental health as an epidemic. Harnad's list is not at all exhaustive, but it will support the point that society benefits from the learning that occurs in debate. WAR AND THE MENTAL HEALTH OF SOLDIERS: ARE THEY EVER PREPARED? As I am writing this, word just came that Osama bin Laden was killed. The relief and rejoicing over the killing of this al-Qaeda leader must also have brought at least some realization to our conscious mind about just where we are with respect to the act of ending the life of another human. Ever since I read Grossman's (1996) book, On Killing: The Psychological Cost of Learning to Kill in War and Society, I have been hypersensitive to the act of killing because it is sanctioned in war. I am not campaigning about any liferelated issue. I am simply reporting my own sensitivity to the subject. Therefore, reading Clark Barrett's article on the mental preparation (or lack thereof) that soldiers received, it brought Grossman's thesis back to mind in stark reality. Humans have to be prepared for war and its associated antilife force. In the lead article in this issue of EHPP, "Unarmed and Dangerous: The Holistic Preparation of Soldiers for Combat," Barrett has presented a compelling picture of the issues involved in this preparation. …

The general factor of personality: Questions and elaborations

Predictions from Rushton’s theory that a general factor of personality (GFP) has evolved based on effective social participation were examined in two large samples of adult Australian twins (5834 and 3672 individuals) and their relatives (8303 and 2677). General factors based on items and scales were compared to each other, across two different questionnaires, and between adults and adolescents. Behavior-genetic analyses based on the twin samples tested predictions comparing GFPs to scales with the GFP partialled out. Some support was found for Rushton’s theory, but the GFP was only marginally more heritable than the GFP-free scales and was not especially marked by the expected non-additivity of its genetic variance; moreover, the adult and adolescent GFPs showed substantial differences.

Etiology of obsessions and compulsions: A behavioral-genetic analysis.

It is unknown whether various types of obsessive-compulsive (OC) symptoms have a common genetic or environmental etiology. For example, it is unknown whether hoarding is etiologically associated with prototypic OC symptoms, such as washing, checking, and obsessing. Also unknown is whether particular OC-related symptoms are etiologically linked to the general tendency to experience emotional distress (negative emotionality). To investigate these and other issues, a community sample of 307 pairs of monozygotic and dizygotic adult twins provided scores on 6 OC-related symptoms (obsessing, neutralizing, checking, washing, ordering, and hoarding) and 2 markers of negative emotionality (trait anxiety and affective lability). Genetic factors accounted for 40%-56% of variance in the 8 phenotypic scores (M = 49% of variance for OC-related symptoms). Remaining variance was due to nonshared (person-specific) environment. More detailed analyses revealed a complex etiologic architecture, where OC-related symptoms arise from a mix of common and symptom-specific genetic and environmental factors. A general genetic factor was identified, which influenced all symptoms and negative emotionality. An environmental factor was identified that influenced all symptoms but did not influence negative emotionality. Each of the 6 types of symptoms was also shaped by its own set of symptom-specific genetic and environmental factors. The importance of genetic factors did not vary as a function of age or sex, and the architecture of general and specific etiologic factors was replicated for participants having relatively more severe OC symptoms. Gene-environment interactions were identified. Implications for an etiology-based classification system are discussed.

Laughter and Resiliency: A Behavioral Genetic Study of Humor Styles and Mental Toughness

This study investigated phenotypic correlations between mental toughness and humor styles, as well as the common genetic and environmental effects underlying these correlations. Participants were 201 adult twin pairs from North America. They completed the Humor Styles Questionnaire, assessing individual differences in two positive (affiliative, self-enhancing) and two negative (aggressive, self-defeating) humor styles. They also completed the MT48, measuring individual differences in global mental toughness and its eight factors (Commitment, Control, Emotional Control, Control over Life, Confidence, Confidence in Abilities, Interpersonal Confidence, Challenge). Positive correlations were found between the positive humor styles and all of the mental toughness factors, with all but one reaching significance. Conversely, negative correlations were found between all mental toughness factors and the negative humor styles, with the mental toughness factors of Control, Emotional Control, Confidence, Confidence in Abilities, and Interpersonal Confidence exhibiting significant correlations. Subsequent behavioral genetic analyses revealed that these phenotypic correlations were primarily attributable to common genetic and common non-shared environmental factors. The implications of these findings regarding the potential effects of humor styles on wellbeing, and the possible selective use of humor by mentally tough individuals are discussed.

Directional asymmetry in the limbs, skull and pelvis of the silver fox (V. vulpes)

Directional asymmetry (DA) is a characteristic of most vertebrates, most strikingly exhibited by the placement of various organs (heart, lungs, liver, etc.) but also noted in small differences in the metrics of skeletal structures such as the pelvis of certain fish or sauropsids. We have analyzed DA in the skeleton of the fox (V. vulpes), using ∼1,000 radiographs of foxes from populations used in the genetic analysis of behavior and morphology. Careful measurements from this robust data base demonstrate that: 1) DA occurs in the limb bones, the ileum, and ischium and in the mandible; 2) regardless of the direction of the length asymmetry vector of a particular skeletal unit, the vectorial direction of length is always opposite to that of width; 3) with the exception of the humerus and radius, there is no correlation or inverse correlation between vectorial amplitudes or magnitudes of bone asymmetries. 4) Postnatal measurements on foxes demonstrate that the asymmetry increases after birth and continues to change (increasing or decreasing) during postnatal growth. 5) A behavior test for preferential use of a specific forelimb exhibited fluctuating asymmetry but not DA. None of the skeletal asymmetries were significantly correlated with a preferential use of a specific forelimb. We suggest that for the majority of fox skeletal parameters, growth on the right and left side of the fox are differentially biased resulting in fixed differences between the two sides in either the rate of growth or the length of the period during which growth occurs. Random effects around these fixed differences perturb the magnitude of the effects such that the magnitudes of length and width asymmetries are not inversely correlated at the level of individual animals.

Associations between diurnal preference, sleep quality and externalizing behaviours: a behavioural genetic analysis

Certain aspects of sleep co-occur with externalizing behaviours in youth, yet little is known about these associations in adults. The present study: (1) examines the associations between diurnal preference (morningness versus eveningness), sleep quality and externalizing behaviours; (2) explores the extent to which genetic and environmental influences are shared between or are unique to these phenotypes; (3) examines the extent to which genetic and environmental influences account for these associations. method: Questionnaires assessing diurnal preference, sleep quality and externalizing behaviours were completed by 1556 young adult twins and siblings. A preference for eveningness and poor sleep quality were associated with greater externalizing symptoms [r=0.28 (95% CI 0.23-0.33) and 0.34 (95% CI 0.28-0.39), respectively]. A total of 18% of the genetic influences on externalizing behaviours were shared with diurnal preference and sleep quality and an additional 14% were shared with sleep quality alone. Non-shared environmental influences common to the phenotypes were small (2%). The association between diurnal preference and externalizing behaviours was mostly explained by genetic influences [additive genetic influence (A)=80% (95% CI 0.56-1.01)], as was the association between sleep quality and externalizing behaviours [A=81% (95% CI 0.62-0.99)]. Non-shared environmental (E) influences accounted for the remaining variance for both associations [E=20% (95% CI -0.01 to 0.44) and 19% (95% CI 0.01-0.38), respectively]. A preference for eveningness and poor sleep quality are moderately associated with externalizing behaviours in young adults. There is a moderate amount of shared genetic influences between the phenotypes and genetic influences account for a large proportion of the association between sleep and externalizing behaviours. Further research could focus on identifying specific genetic polymorphisms common to both sleep and externalizing behaviours.

A Behavioral Genetic Study of Relationships Between Humor Styles And The Six HEXACO Personality Factors

In this study, four humor styles (affiliative, self-enhancing, aggressive, self-defeating) were assessed in conjunction with a measure of the HEXACO model of personality, in order to gain greater insight into the etiology of these humor styles, and to situate them better in the framework of human personality. Participants were 664 monozygotic twin pairs and 522 dizygotic twin pairs from the United Kingdom who completed the Humor Styles Questionnaire and the HEXACO Personality Inventory. Univariate behavioral genetic analyses of the HEXACO revealed that individual differences in all of its dimensions were entirely attributable to additive genetic and non-shared environmental factors. Significant phenotypic correlations were found between many of the HEXACO factors and the four humor styles, and bivariate behavioral genetic analyses revealed that these correlations were themselves accounted for entirely by correlated genetic and correlated non-shared environmental factors. Our study adds to the literature validating humor as a personality construct and assessing its relations to psychological well-being.