A behavioral genetic analysis of the relationship between the socialization scale and self-reported delinquency

This investigation examined the genetic (A), and shared (C) and nonshared (E) environmental variance contributions to the relationship of self-reported delinquency (as measured by the "Delinquent Behavior Inventory" [DBI; Gibson, 1967]) to the Socialization (So) scale of the California Psychological Inventory using univariate and bivariate structural equation models. The scales were administered to 222 male (145 monozygotic; 77 dizygotic) and 159 female (107 monozygotic; 52 dizygotic) 16- to 18-year-old same-sex twin pairs. Principal components analysis with varimax rotation revealed three interpretable So factors representing family/home environment, self-concept, and behavioral control. Univariate modeling suggested sex differences in etiological influences associated with individual differences in most scales. The bivariate ACE model fit the data, suggesting that the covariance between the So scale and self-reported delinquency owes in part to shared etiological factors.     

Personality Dimensions as Common and Broadband-Specific Features for Internalizing and Externalizing Disorders

Several researchers have suggested that the nature of the covariation between internalizing and externalizing disorders may be understood better by examining the associations between temperament or personality and these disorders. The present study examined neuroticism as a potential common feature underlying both internalizing and externalizing disorders and novelty seeking as a potential broad-band specific feature influencing externalizing disorders alone. Participants were 12- to 18-year-old twin pairs (635 monozygotic twin pairs and 691 dizygotic twin pairs; 48 % male and 52 % female) recruited from the Colorado Center for Antisocial Drug Dependence. Genetic and nonshared environmental influences shared in common with neuroticism influenced the covariation among distinct internalizing disorders, the covariation among distinct externalizing disorders, and the covariation between internalizing and externalizing disorders. Genetic influences shared in common with novelty seeking influenced the covariation among externalizing disorders and the covariation between major depressive disorder and externalizing disorders, but not the covariation among internalizing disorders or between anxiety disorders and externalizing disorders. Also, after accounting for genetic and environmental influences shared in common with neuroticism and novelty seeking, there were no significant common genetic or environmental influences among the disorders examined, suggesting that the covariance among the disorders is sufficiently explained by neuroticism and novelty seeking. We conclude that neuroticism is a heritable common feature of both internalizing disorders and externalizing disorders, and that novelty seeking is a heritable broad-band specific factor that distinguishes anxiety disorders from externalizing disorders.     

Sex differences in the genetic and environmental influences on childhood conduct disorder and adult antisocial behavior

Sex differences in the genetic and environmental influences on childhood conduct disorder and adult antisocial behavior were examined in a large community sample of 6,383 adult male, female, and opposite-sex twins. Retrospective reports of childhood conduct disorder (prior to 18 years of age) were obtained when participants were approximately 30 years old, and lifetime reports of adult antisocial behavior (antisocial behavior after 17 years of age) were obtained 8 years later. Results revealed that either the genetic or the shared environmental factors influencing childhood conduct disorder differed for males and females (i.e., a qualitative sex difference), but by adulthood, these sex-specific influences on antisocial behavior were no longer apparent. Further, genetic and environmental influences accounted for proportionally the same amount of variance in antisocial behavior for males and females in childhood and adulthood (i.e., there were no quantitative sex differences). Additionally, the stability of antisocial behavior from childhood to adulthood was slightly greater for males than females. Though familial factors accounted for more of the stability of antisocial behavior for males than females, genetic factors accounted for the majority of the covariation between childhood conduct disorder and adult antisocial behavior for both sexes. The genetic influences on adult antisocial behavior overlapped completely with the genetic influences on childhood conduct disorder for both males and females. Implications for future twin and molecular genetic studies are discussed.     

Psychometric properties of the Wolpe-Lazarus assertiveness scale

The psychometric properties of the Wolpe-Lazarus Assertiveness Scale (WLAS) were evaluated with a sample of 100 male and 157 female psychiatric patients. There were no significant differences with regard to males and females for total WLAS scores. The WLAS seems to be internally consistent and has acceptable split-half and test-retest reliabilities. A factor analysis performed separately for males and females indicates that the 10 most prominent factors account for about 60% of the accumulated variance. The primary factor, shared by males and females, was labeled General Expressiveness. There was little evidence for the external validity of the WLAS when total scores were correlated with performance on a role play test. However, when WLAS factor scores were evaluated in light of role played performance, somewhat better evidence of the external validity of the WLAS was found in two of the factors for the females.     

Etiologic connections among substance dependence,antisocial behavior,and personality: modeling the externalizing spectrum

A hierarchical biometric model is presented of the origins of comorbidity among substance dependence, antisocial behavior, and a disinhibited personality style. The model posits a spectrum of personality and psychopathology, united by an externalizing factor linked to each phenotype within the spectrum, as well as specific factors that account for distinctions among phenotypes within the spectrum. This model fit self-report and mother-report data from 1,048 male and female 17-year-old twins. The variance of the externalizing factor was mostly genetic, but both genetic and environmental factors accounted for distinctions among phenotypes within the spectrum. These results reconcile evidence for general and specific causal factors within the externalizing spectrum and offer the externalizing factor as a novel target for future research.     

Loneliness, social interaction, and sex roles

Forty-three male and 53 female college seniors maintained the Rochester Interaction Record for 2 weeks, providing information about every social interaction of 10 minutes or more. Subjects then completed the revised UCLA (University of California, Los Angeles) Loneliness Scale and the Personal Attributes Questionnaire, measuring sex-role orientation. For both sexes, loneliness was negatively related to the amount of time spent with females and to the meaningfulness of interaction with males and females. However, meaningfulness with males was more important than meaningfulness with females. Femininity was negatively related to loneliness for both sexes and partially mediated the above relationships. There were sex differences, however, in the extent to which variables overlapped in predicting loneliness. For example, a large group of nonlonely males was characterized both by having meaningful relationships with males and by spending time with females, whereas a second group of nonlonely males was characterized simply by having meaningful relationships with males. The largest group of nonlonely females was characterized simply by having meaningful relationships with males, but another sizable group was characterized simply by spending time with females. Females doing both accounted for very little of the variance.     

Genetic and environmental influences on antisocial behavior: a meta-analysis of twin and adoption studies

A meta-analysis of 51 twin and adoption studies was conducted to estimate the magnitude of genetic and environmental influences on antisocial behavior. The best fitting model included moderate proportions of variance due to additive genetic influences (.32), nonadditive genetic influences (.09), shared environmental influences (.16), and nonshared environmental influences (.43). The magnitude of familial influences (i.e., both genetic and shared environmental influences) was lower in parent-offspring adoption studies than in both twin studies and sibling adoption studies. Operationalization, assessment method, zygosity determination method, and age were significant moderators of the magnitude of genetic and environmental influences on antisocial behavior, but there were no significant differences in the magnitude of genetic and environmental influences for males and females.     

Male and female delinquency trajectories from pre through middle adolescence and their continuation in late adolescence

This study of male and female adolescent delinquency trajectories focuses on the prediction of late adolescence delinquency, based on earlier delinquency and social support. In this 3-wave longitudinal survey, 270 Dutch adolescents (113 males and 157 females) ages 12 to 14, were followed for a period of 6 years. For males, the level of delinquent activity in late adolescence strongly depends on earlier delinquent activities (R2 = .33, p < .0005). In contrast, the level of female delinquency in late adolescence is far less predictable (R2 = .18, p < .001), and could not be predicted from delinquent activities during pre and early adolescence, while support from the mother during late adolescence was associated with reduced delinquency for females. Different models may be needed to explain the development of delinquency for males versus females.     

Delinquency, sidedness, and sex

One hundred and thirty male and 213 female college students responded to a self-report delinquency and crime measure and to a scale of sidedness preferences. Consistent with most of the literature on official delinquency and crime, left handedness was positively associated with involvement in several forms of delinquency (including some degree of criminality) among males. Other measures of sidedness among males largely failed to correlate with delinquency, however. Among females, sidedness was much less systematically related to delinquency than among males.     

Evidence for the Trait-Impulsivity Etiological Model in a Clinical Sample: Bifactor Structure and Its Relation to Impairment and Environmental Risk

The trait-impulsivity etiological model assumes that a general factor (trait-impulsivity) underlies attention-deficit/hyperactivity disorder (ADHD), oppositional defiant disorder (ODD), and other externalizing disorders. We investigated the plausibility of this assumption by testing the factor structure of ADHD and ODD in a bifactor framework for a clinical sample of 1420 children between 6 and 18 years of age (M = 9.99, SD = 3.34; 85% male). Further, the trait-impulsivity etiological model assumes that ODD emerges only if environmental risk factors are present. Our results support the validity of the trait-impulsivity etiological model, as they confirm that ADHD and ODD share a strong general factor of disruptive behavior (DB) in this clinical sample. Furthermore, unlike the subdimensions of ADHD, we found that the specific ODD factor explained as much true score variance as the general DB factor. This suggests that a common scale of ADHD and ODD may prove to be as important as a separate ODD subscale to assess externalizing problems in school-age children. However, all other subscales of ADHD may not explain sufficient true score variance once the impact of the general DB factor has been taken into consideration. In accordance with the trait-impulsivity model, we also showed that all factors, but predominantly the general factor and specific inattention factor, predicted parent-rated impairment, and that predominantly ODD and impulsivity are predicted by environmental risk factors.     

Identifying shared environmental contributions to early substance use: the respective roles of peers and parents

Although behavior genetic studies have suggested that early substance use is primarily environmentally mediated, no study has sought to identify the specific sources of environmental variance. Using data obtained from multiple informants, this study assessed the contributions of peer deviance and parent-child relationship problems to substance use in 14-year-old male and female twins (N = 1,403) drawn from the Minnesota Twin Family Study (MTFS). All three phenotypes were influenced primarily by shared environmental variance (average c(2) =.51), as was the overlap among them. Moreover, peer deviance and parent-child relationship problems accounted for approximately 77% of the variance in early substance use. Findings also indicated that peer deviance, but not parent-child relationship problems, accounted uniquely for variance in early substance use.     

Heritabilities of Common and Measure-Specific Components of the Big Five Personality Factors

Three different measures of the Big Five personality dimensions were developed from the battery of questionnaires used in the National Merit Twin Study: one from trait self-rating scales, one from personality inventory items, and one from an adjective check list. Behavior-genetic models were fit to what the three measures had in common, and to the variance distinctive to each. The results of the model fitting agreed with other recent studies in showing the Big Five dimensions to be substantially and about equally heritable, with little or no contribution of shared family environment. Heritabilities for males and females did not differ significantly. For Agreeableness and Conscientiousness, some effect of shared environment was found for measure-specific variance on the personality inventory, and for Extraversion and Neuroticism, models involving nonadditive genetic variance or twin contrast effects provided slightly better fits.     

Etiological Distinctions between Aggressive and Non-aggressive Antisocial Behavior: Results from a Nuclear Twin Family Model

A recent meta-analysis of 103 studies Burt (Clinical Psychology Review, 29:163-178, 2009a) highlighted the presence of etiological distinctions between aggressive (AGG) and non-aggressive rule-breaking (RB) dimensions of antisocial behavior, such that AGG was more heritable than was RB, whereas RB was more influenced by the shared environment. Unfortunately, behavioral genetic research on antisocial behavior to date (and thus, the research upon which the meta-analysis was based) has relied almost exclusively on the classical twin model. This reliance is problematic, as the strict assumptions that undergird this model (e.g., shared environmental and dominant genetic influences are not present simultaneously; there is no assortative mating) can have significant consequences on heritability estimates when they are violated. The nuclear twin family model, by contrast, allows researchers to relax and statistically evaluate many of the assumptions of the classical twin design by incorporating parental self-report data along with the more standard twin data. The goal of the current study was thus to evaluate whether prior findings of etiological distinctions between AGG and RB persisted when using the nuclear twin family model. We examined a sample of 312 child twin families from the Michigan State University Twin Registry. Results strongly supported prior findings of etiological distinctions between AGG and RB, such that broad genetic influences were observed to be particularly important to AGG whereas shared environmental influences contributed only to RB. Nevertheless, the current findings also implied that additive genetic influences on antisocial behavior may be overestimated when using the classical twin design.     

Gender differences in the relationship of moderator variables to stress and symptoms

Abstract

This study focused on gender differences in the relationship of four moderator variables (hostility, social support, optimism, and Type A behavior) to perceptions of symptoms and stress based on a sample of 120 female and 79 male undergraduates. Results confirmed significant gender differences in hostility, Type A behavior, and social support but not in optimism. Multiple regression analyses exposed distinct gender differences. For females, social support accounted for 21% and hostility 5% of the total variance in perceived stress. For males, only hostility accounted for any significant variance (10%). Hostility contributed 21% and social support contributed 13% to the total variance in the number of symptoms for females. For males, optimism contributed 14% and hostility 5%. Results indicate that social support is a potent variable for females in their perception of both stress and symptoms but essentially unrelated for males. Hostility, however, relates to perceptions of stress and symptoms for both sexes.     

Sexual Peak: Socially Shared Cognitions About Desire,Frequency, and Satisfaction in Men and Women

Is a man’s sexual peak earlier than a woman’s? Three studies were conducted to examine (a) whether the perception that men achieve their sexual peak at a younger age than do women is shared across individuals of different ages and sexes, (b) whether sexual peak is defined differently for men and women, and (c) whether differences between definitions contribute to differences in the age at which men and women are perceived to reach sexual peak. Study 1 suggested that participants believed that females reach their sexual peak at an older age than do males. Study 2 indicated that the defining feature of sexual peak for males was sexual desire and for females was sexual satisfaction. Study 3 suggested that predictions of male sexual peak coincided with participants’ predictions of male age of highest desire and frequency, but not satisfaction, and that female sexual peak coincided with participants' predictions of female age of highest satisfaction but not frequency or desire. Discussion focuses on potential reasons for differences between the perception of male and female sexuality, as well as the social and evolutionary importance of each of the dimensions of sexuality for both males and females.     

Spatial visualization and sex differences in quantitative ability

The hypothesis that sex differences in spatial visualization ability might account for sex differences in mathematical ability was supported for a group of 183 male and 81 female college students. With spatial visualization statistically controlled, no significant sex differences in Quantitative Scholastic Aptitude Test (QSAT) scores was found; including sex as a predictor variable increased the variance explained by less than 1%. Although the slope of the regression of mathematics on spatial visualization did not differ as a function of sex, males were somewhat more predictable than females. As the OSAT of both males and females high on spatial visualization was more predictable than the QSAT of those scoring less well, it appears that the sex difference in predictability is due to males having higher spatial ability than females.     

Common Etiological Sources of Anxiety,Depression, and Somatic Complaints in Adolescents: A Multiple Rater twin Study

Somatic complaints in children and adolescents may be considered part of a broader spectrum of internalizing disorders that include anxiety and depression. Previous research on the topic has focused mainly on the relationship between anxiety and depression without investigating how common somatic symptoms relate to an underlying factor and its etiology. Based on the classical twin design with monozygotic and dizygotic twins reared together, our study aimed to explore the extent to which the covariation between three phenotypes in adolescent girls and boys can be represented by a latent internalizing factor, with a focus on both common and specific etiological sources. A population-based sample of twins aged 12–18 years and their mothers and fathers (N?=?1394 families) responded to questionnaire items measuring the three phenotypes. Informants’ ratings were collapsed using full information maximum likelihood estimated factor scores. Multivariate genetic analyses were conducted to examine the etiological structure of concurrent symptoms. The best fitting model was an ACE common pathway model without sex limitation and with one substantially heritable (44 %) latent factor shared by the phenotypes. Concurrent symptoms also resulted from shared (25 %) and non-shared (31 %) environments. The factor loaded most on depression symptoms and least on somatic complaints. Trait-specific influences explained 44 % of depression variance, 59 % of anxiety variance, and 65 % of somatic variance. Our results suggest the presence of a general internalizing factor along which somatic complaints and mental distress can be modeled. However, specific influences make the symptom types distinguishable.     

Examining genetic and environmental effects on reactive versus proactive aggression

This study compared the contribution of genes and environment to teacher-rated reactive and proactive aggression in 6-year-old twin pairs (172 pairs: 55 monozygotic girls, 48 monozygotic boys, 33 dizygotic girls, 36 dizygotic boys). Genetic effects accounted for 39% of the variance of reactive aggression and for 41% of the variance of proactive aggression. The remainder of the variance was explained by unique environmental effects. Genetic as well as unique environmental effects were significantly correlated across reactive and proactive aggression (genetic correlation = .87, environmental correlation = .34), but this overlap was largely due to a common underlying form of aggression (i.e., teacher-rated physical aggression). Once common etiological factors due to physical aggression were accounted for, reactive and proactive aggression shared no other genes and only a few environmental influences, although additional specific genetic and environmental effects were observed for both reactive and proactive aggression. These specific effects indicate that both reactive and proactive aggression may be influenced mostly by socialization experiences that are specific to each type of aggression and only to a very small degree by specific genes.