Genetic and Rearing Environmental Influences on Adult Personality: An Analysis of Adopted Twins Reared Apart

ABSTRACT We report a genetic and environmental analysis of California Psychological Inventory (CPI) scale scores gathered on a sample of 45 sets of monozygotic twins reared apart (MZA) and 26 sets of dizygotic twins reared apart (DZA) Analysis of twin intraclass correlations and the results of models fit to the twin data demonstrate that the heritability of most scales and five factors of the CPI is about 50 When compared to results from studies of adult MZ and DZ twins reared together few of the scales demonstrate any common family environmental influence Placement coefficients on the Family Environment Scale (FES) can explain only a minor portion of the correlations for twins reared apart The influence of specific rearing environmental factors on adult personality was evaluated by analyzing the relationship between the FES and the CPI in this adoptee sample One FES factor (Cohesion vs Conflict) does correlate substantially with the CPI factor of Consensuality and may account for up to 24% of the variance in that factor, but the retrospectively gathered     

Genetic and Environmental Influences on the Continuous Scales of the Myers-Briggs Type Indicator: An Analysis Based on Twins Reared Apart

The Myers-Briggs Type Indicator was administered to a sample of 61 monozygotic twins reared apart (MZA), 49 dizygotic twins reared apart (DZA), and 92 spouses, who participated in the Minnesota Study of Twins Reared Apart (MISTRA) from 1979 to 1995. Twins' scores on the continuous scales were subjected to behavior genetic model-fitting procedures. Extraversion-Introversion and Thinking-Feeling yielded heritabilities of about .60, consisting largely of nonadditive genetic variance. Sensing-Intuition and Judgment-Perception yielded heritabilities of about .40, consisting largely of additive genetic variance. Spouse correlations for three of the four scales were near zero and not statistically significant; one spouse correlation (Sensing-Intuition) was modestly positive and statistically significant.     

Deviant Peer Affiliation and Problem Behavior: A Test of Genetic and Environmental Influences

This study uses a multitrait, multimethod (MTMM) approach to investigate the genetic and environmental etiologies of childhood deviant peer affiliation (DPA) and problem behavior (PROB). The variability of genetic and environmental estimates by agent and method is also examined. A total of 77 monozygotic and 72 dizygotic twin pairs and each twin's close friend were assessed. The informants included parents, teachers, and twins, and the methods involved questionnaire reports and coder ratings of videotaped dyadic interactions between each twin and their close friend. Twin intraclass correlations and univariate models attributed DPA and PROB to genetic, and shared and nonshared environmental effects. Parameter estimates differed by rater and method, however. Results accentuate the imperative to attend to method effects inherent in MTMM behavioral geneticresearch.     

Genetic and Environmental Influences on the Development and Stability of Executive Functions in Children of Preschool Age: A Longitudinal Study of Japanese Twins

Executive functions (EF) are an important predictor of later adaptive development. A number of environmental influences, such as parenting, have been suggested as important promoters of EF development. However, behavioural genetic research has demonstrated that many environmental influences could be affected by genetic influences. Therefore, it is important to consider genetic variations when investigating environmental influences on EF development in children. To date, few studies have used genetically informative designs to assess the etiology of EF development during the preschool years, a period of rapid development. As a result, it remains unclear how and to what extent the environmental influences that are not confounded by genetic influences affect EF development during this developmental period. The present study explored EF development during the preschool years using a longitudinal and genetically informative design and a non‐Western population. Japanese twins were visited at their homes and individually tested on EF measures at 24, 36, and 48 months of age. Phenotypic correlations and confirmatory factor analyses suggested that EF are less cohesive at 24 months of age and emerge as a common single factor at 36 and 48 months. Additionally, longitudinal and multivariate behavioural genetic analyses indicated that the EF developmental change during this period is promoted by both shared and nonshared environmental influences as well as genetic influences, while EF stability is brought about by shared environments. The present findings elucidated the etiology of EF development during the preschool years and confirmed that this period is an important transitional stage for EF development. Copyright © 2016 John Wiley & Sons, Ltd.     

Genetic and Environmental Influences on Psychopathy Trait Dimensions in a Community Sample of Male Twins

Psychopathy appears to be comprised of two broad dimensions: impulsivity/antisocial behavior and interpersonal detachment/callousness. This study examined the extent to which variance in these 2 psychopathy trait dimensions was associated with common or unique genetic, shared, and nonshared environmental factors in two independent samples of reared together 16–18-year-old male twins. One sample included 142 monozygotic (MZ) and 70 dizygotic (DZ) pairs; the other sample included 128 MZ and 58 DZ pairs. Boys completed the Minnesota Temperament Inventory (MTI), a 19-item measure that contains separate subscales: Antisocial and Detachment. Variance in the Antisocial and Detachment scales was associated with additive genetic factors and neither scale was associated with shared environmental factors. As expected, the bivariate biometric analysis suggested genetic influence on the covariance of the scales. The results are consistent with theoretical models of psychopathy that posit some independence in the etiology of the two major trait dimensions of psychopathy.     

Genetic and Environmental Contributions to Common Psychopathologies of Childhood and Adolescence: A Study of Twins and Their Siblings

We report findings based on analyses of self-reports of six common adolescent psychopathologies (attention deficit/hyperactivity disorder, ADHD; conduct disorder, CD; oppositional defiant disorder, ODD; generalized anxiety disorder, GAD; separation anxiety disorder, SAD; and major depressive disorder, MDD) in a sample of 1,162 male and female adolescent (12–19 years) twin pairs and 426 siblings. Prevalence statistics for past year and lifetime reports confirm differences between genders for CD, GAD, SAD, and MDD, and a lack of differences between twins and their non-twin siblings. Biometrical modeling was conducted to ascertain the relative influences of genes, and shared and non-shared environments contributing to these disorders. A more robust estimate of these parameters was obtained by including non-twin siblings. Age-specific thresholds were integrated into the analyses to appropriately model the developmental patterns of behavior. We found evidence for both genetic and non-shared environmental influences for all disorders. Shared environmental influences also seem to be important for MDD and lifetime GAD.     

A Rorschach Study of Personality Development In Identical and Fraternal Twins

To determine whether identical twins show greater resemblances in their general personality make-up than fraternals, seven pairs of identical and eight pairs of fraternal twins were studied using the Rorschach Inkblot test. The results of the inter-twin correlations, on the various Rorschach categories indicated clearly striking similarity or resemblance in identical twins, but no similarity in the case of fraternal twins. This study also clearly demonstrated the usefulness of the Rorschach technique for the study of personality.     

Genetic and Environmental Influences on Two Measures of Speed of Information Processing and their Relation to Psychometric Intelligence: Evidence from the German Observational Study of Adult Twins

Speed of information processing, as measured by reaction times (RTs) in elementary cognitive tasks (ECTs), has been found to be an important correlate of human psychometric intelligence. While the heritability of psychometric intelligence is well understood, we know only a little about genetic and environmental influences on ECT performance, particularly about genetic and environmental contributions to ECT–intelligence relation. These questions were studied by employing two widely used ECTs (Sternberg's memory scanning and Posner's letter-matching task) as well as two psychometric intelligence tests (Advanced Progressive Matrices and Leistungs–Prüf System) in a large sample of 169 monozygotic (MZ) and 131 dizygotic (DZ) twin pairs. As expected, RTs correlated negatively with psychometric intelligence. Moreover, heritability estimates were substantial for both psychometric intelligence and RTs in ECTs. Finally, multivariate genetic analyses suggested that most of the phenotypic correlation between mental speed and intelligence is due to genetic factors.     

Genetic and Environmental Variation on the California Psychological Inventory Vector Scales

Three recently introduced vector scales for the California Psychological Inventory (CPI) were scored for the National Merit Twin Sample and subjected to a heredity-environment analysis. Confidence intervals for genetic and environmental parameters were obtained by a bootstrap method. Two of the scales, Internality (Vector 1) and Self-Realization (Vector 3), showed the substantial heritability and near-zero family environment effects typically found for personality scales, whereas Norm-Favoring (Vector 2) showed an appreciable effect of family environment and a nonsignificant heritability.     

分离遗传与环境对儿童发展的影响：介绍一个新颖的研究方法

本文介绍一个可以用于研究遗传与环境互动的新颖方法。此研究收集了上千个4~10岁儿童的数据。这些儿童的出生都借助于不同的辅助受孕技术（Assisted Reproductive Technologies）,包括试管婴儿、精子捐赠、卵子捐赠、胚胎捐赠及代孕技术。本项目通过妇科（助孕）医院收集被试的行为数据,包括家庭互动、养育方式、父母婚姻质量、家庭成员的心理健康及经济状况等。本文选择性地介绍一些分析的结果,以彰显这种设计在分离遗传和产前产后环境对儿童发展的贡献。首先,我们比较了“助孕”儿童与“自然孕”儿童在父母冲突、父母对子女敌意以及儿童抑郁症状之间关系的异同。其次,我们比较了这两组儿童在父母抑郁症状、家庭关系质量以及儿童抑郁症状之间关系的异同。再次,本文介绍了这一可分离遗传与环境因素的研究设计。最后,我们讨论了这一设计对发展心理病干预及预防的意义     

Environmental Influences on Fighting Versus Nonviolent Behavior in Peer Situations: A Qualitative Study with Urban African American Adolescents

This qualitative study explored environmental factors that influence adolescents’ responses to problem situations involving peers. Interviews were conducted with 106 middle school students (97% African American) from an urban school system. Participants were asked to describe factors that would make it easier and those that would make it more difficult for adolescents to make specific responses to problem situations. Two types of responses were presented: nonviolent responses identified as effective in a previous study, and fighting responses. Qualitative analysis identified 24 themes representing family, peer, school, and neighborhood and broader social factors that were related to both nonviolent behavior and fighting. The identification of environmental influences on fighting and nonviolent responses has important implications for efforts to reduce aggression and promote effective nonviolent responses to problem situations encountered by adolescents.     

Normal and abnormal personality traits: evidence for genetic and environmental relationships in the Minnesota Study of Twins Reared Apart

ABSTRACT Recent studies have demonstrated substantial correlations between normal and abnormal personality traits. Yet little is known about how these correlations are mediated genetically and environmentally: Do normal and abnormal personality traits stem from the same underlying genes and environments? We addressed this question using data from 128 monozygotic and dizygotic twin pairs in the Minnesota Study of Twins Reared Apart (MISTRA). Additive genetic and nonshared environmental correlations between scales of the Minnesota Multiphasic Personality Inventory (MMPI)—an index of abnormal personality—and the Multidimensional Personality Questionnaire (MPQ)—an index of normal personality—were estimated. Results indicated that phenotypic correlations between normal and abnormal personality were mediated by genetic as well as environmental factors, although the magnitude of genetic mediation tended to be larger overall. Moreover, the patterns of phenotypic, genetic, and environmental relationships among the scales were similar, suggesting that influences on normal and abnormal personality act through systems common to both. It is suggested that future research focus on the neurogenetic substrates of these shared systems and how dysfunction in these systems influences development of disordered personality.     

Genetic and Environmental Influences on Personal and Rhythmic‐Motor‐Activity Tempo in Children: A Twin Study

In this study, we investigated the degree to which genetics and environmental factors influence the tempo and tempo stability of rhythmic motor activity in young children, using a twin study design. A total of 116 twin children, aged 4 years, were asked to strike two small clash cymbals together in a cyclical manner, in three phases. In the first phase, children were asked to maintain a comfortable personal tempo of rhythmic motor activity (spontaneous motor phase). In contrast, in the other phases, children were required to synchronize rhythmic motor activity in response to the timing of a stimulus tone, or a memorized tempo. Large additive genetic, although negligible shared environmental influences, were observed in the spontaneous motor phase. However, environmental factors were estimated in the other two phases, while the additive genetic factor was nearly zero. These results indicate that the extent of genetic and environmental influences on individual differences in rhythmic motor activity can be modulated under different situations.     

青少年抑郁情绪的行为遗传学研究

本研究意在探讨青少年抑郁情绪遗传率的性别和年龄差异及遗传和环境对抑郁情绪跨时间连续性的影响。508对同卵双生子, 176对同性别异卵双生子参加了两轮追踪研究, 时间间隔约为一年半(1.37±0.44)。第一轮测量双生子的年龄范围为10~18岁, 平均年龄为13.69±2.04岁, 男生比例为46.2%。采用儿童抑郁量表(CDI)对青少年的抑郁情绪进行多报告者评定。结果发现, 青少年抑郁情绪的遗传解释率不存在性别差异, 处于青春早期青少年的遗传解释率高于青春中期的青少年。遗传是影响青春早期青少年抑郁情绪持续发生的主导因素, 而环境是影响青春中期青少年抑郁情绪持续发生的主要因素。     

The Heritability of Job Satisfaction Reconsidered: Only Unique Environmental Influences Beyond Personality

Purpose

The purpose of this study was to investigate the degree to which genetic and environmental influences explain differences in job satisfaction and its relationship to personality in order to explain the heritability of job satisfaction.

Design

Behavior genetic analyses are based on a dataset containing 622 individuals, including 185 MZ (M = 39.5 years) and 126 DZ twin pairs (M = 40.1 years).

Findings

The results showed that all genetic influences (28 %) on job satisfaction could be explained by its relation to personality, especially Neuroticism, Extraversion, and Conscientiousness, representing a high genetic overlap between job satisfaction and personality. Non-shared environmental influences explained the remaining three fourths of the variance.

Implications

By showing that genetic influences of job satisfaction overlap completely with personality, including common non-additive genetic influences, the results support an interactionist view of job satisfaction in that both situational and dispositional determinants of job satisfaction are relevant.

Originality

In contrast to previous studies, we used a more appropriate behavior genetic approach meaning that our approach allows to directly estimate parameters of specific and common (additive and non-additive) genetic and environmental influences. Building on this, interpretations of behavior genetic findings were explained in detail to avoid common misunderstandings.

     

Genetic and environmental influences on observed personality: evidence from the German Observational Study of Adult Twins

Previous behavior-genetic research on adult personality relied primarily on self-reports or peer reports that may be subject to contrast effects, resulting in biased estimates of genetic and environmental influences. In the German Observational Study of Adult Twins (GOSAT), personality traits of 168 monozygotic (MZ) and 132 dizygotic (DZ) twin pairs were rated on 35 adjective scales, largely markers of the Big 5. The ratings were provided by 120 judges who never met the twins but observed videotaped behaviors of 1 twin of each pair in 1 of 15 different settings. The aggregated video-based trait ratings were highly reliable, and substantial correlations were obtained between MZ as well as DZ twins. Model-fit analyses suggested about 40% genetic, 25% shared environmental, and 35% nonshared environmental influence. Extraversion was the only trait that seemed not to be influenced by shared environment.     

个性测验研制报告

本研究所编制的个性测验是根据我国企业人才素质测评需要而设计的,它包含有一个效度量表(掩饰性)和15项个性测评要素：自信心、责任心、自律性、进取性、合群性、灵活性、自主性、支配性、客观性、外向性、情绪性、宽容性、坚韧性、成就性、内外控。项目分析和信度、效度分析结果显示,该测验是可靠而有效的。     

同伴侵害与人际关系取向人格特质的交叉滞后分析:城市原住儿童与农村随迁儿童的比较

研究采用间隔两年的追踪设计,分析了477名农村随迁儿童（男生57.10%;2014年时平均年龄为11.54±0.64岁）与245名城市原住儿童（男生50.60%;2014年时平均年龄为11.36±0.51岁）的同伴侵害与和谐性、人际触觉两个人际关系取向人格维度的相互影响。这些儿童分别来自上海市采取融合教育的四所公立初中。他们首次参加本研究时为初中预备年级。交叉滞后分析表明,（1）在原住儿童组,时间1的同伴侵害可以负向预测时间2的和谐性与人际触觉;（2）在随迁儿童组,和谐性与同伴侵害有负向循环作用关系,且时间1的同伴侵害可以负向预测时间2的人际触觉。研究一定程度上揭示了人际人格发展与所处环境（特别是同伴侵害的不利环境）的动态相互作用模式。文章最后讨论了原住儿童与随迁儿童混合编班的融合教育模式对所有城市儿童适应社会转型的现实意义。