Behavioral Genetic Studies Research Articles

The heritability of personality factors in chimpanzees (Pan troglodytes).

Human personality and behavior genetic studies have resulted in a growing consensus that five heritable factors account for most variance in human personality. Prior research showed that chimpanzee personality is composed of a dominance-related factor and five human-like factors--Surgency, Dependability, Emotional Stability, Agreeableness, and Openness. Genetic, shared zoo, and nonshared environmental variance components of the six factors were estimated by regressing squared phenotypic differences of all possible pairs of chimpanzees onto 1 - Rij, where Rij equals the degree of relationship and a variable indicating whether the pair was housed in the same zoo. Dominance showed significant narrow-sense heritability. Shared zoo effects accounted for only a negligible proportion of the variance for all factors.

Understanding biological and social influences on religious affiliation, attitudes, and behaviors: a behavior genetic perspective.

Although the transmission of religiousness has been assumed to be purely cultural, behavior genetic studies have demonstrated that genetic factors play a role in the individual differences in some religious traits. This article reviews the extant behavior genetic literature and presents new analyses from the "Virginia 30,000" on the causes of variation in religious affiliation, attitudes, and practices, and relates these to personality as construed by Eysenck. Results indicate that religious affiliation is primarily a culturally transmitted phenomenon, whereas religious attitudes and practices are moderately influenced by genetic factors. Further, Eysenck's personality traits do not mediate genetic influences on religiousness, but significant negative genetic correlations are found between church attendance and liberal sexual attitudes. Implications and possibilities for future studies are discussed.

Perceived competence and self-worth during adolescence: a longitudinal behavioral genetic study.

This investigation is the first longitudinal behavioral genetic study of self-concept during adolescence. It is a follow-up of a previous study examining genetic and environmental contributions to children's perceived self-competence and self-worth using a twin/sibling design. The study investigated adolescents' reports 3 years later and stability across two time points. Participants included 248 pairs of same-sex twins, full siblings, and stepsiblings between 10 and 18 years old. The results showed that six of the seven subscales were heritable at the second time point. None of the scales showed significant shared environmental effects. Longitudinal analyses revealed genetic contributions to stability for perceived scholastic competence, athletic competence, physical appearance, and general self-worth. Social competence, on the other hand, showed nonshared environmental mediation across time. These findings highlight the importance of genetically influenced characteristics and unique experiences as correlates of individual differences in self-concept during adolescence.

Transmission of religion and attitudes.

The collection of papers in this special edition of Twin Research represents a small landmark in the study of behavioral genetics. The work published here is the fruit of an invited three-day workshop, which was specifically devoted to the task of placing varieties of religious experience and practice within a behaviour - genetic context.

The genetics of schizophrenia.

Behavioral genetic studies provide overwhelming evidence that genes contribute to schizophrenia. Recently, genetic studies have provided promising evidence that schizophrenia genes are linked to several chromosomal locations in affected family members. Despite this progress, individual genes for schizophrenia have yet to be identified. Future progress will depend, in part, on the selection of phenotypes that best reflect effects of etiologic genes. One such phenotype is schizotaxia, a clinically meaningful syndrome that reflects the genetic liability to schizophrenia in nonpsychotic individuals. The potential importance of schizotaxia, or similar concepts, for use in genetic studies, is discussed.

Minor physical anomalies, dermatoglyphic asymmetries, and cortisol levels in adolescents with schizotypal personality disorder.

A relationship between schizotypal personality disorder and schizophrenia has been documented in behavioral genetic studies, and there are similarities in the cognitive deficits and brain abnormalities associated with these disorders. Adolescents with schizotypal personality disorder are of particular interest because the postpubertal period is a critical one for the development of a DSM axis I disorder. It is likely that some schizotypal adolescents will remain stable over time, some will improve, and a subgroup will develop schizophrenia. This study tested the hypotheses that, like schizophrenic patients, schizotypal adolescents manifest an elevated rate of minor physical and dermatoglyphic anomalies, both of which suggest prenatal neurodevelopmental abnormalities. Cortisol release is also of interest because of evidence that the hypothalamic-pituitary-adrenal axis may influence the behavioral expression of vulnerability to schizophrenia. Minor physical anomalies, dermatoglyphic asymmetries, and salivary cortisol levels were measured in three groups of adolescents: 20 with schizotypal personality disorder, 20 with other personality disorders, and 26 with no disorder. Assessments began at noon, and four saliva samples were obtained at hourly intervals. The schizotypal personality disorder group showed more minor physical anomalies and dermatoglyphic asymmetries than the normal comparison group and higher cortisol levels than both of the other groups. Group differences in cortisol level were most pronounced at the beginning of the evaluation. Cortisol level and age were positively correlated. The findings support the assumption that schizotypal personality disorder is associated with perturbations in fetal neurodevelopment and, under some circumstances, a heightened cortisol response.

Individual differences in multiple dimensions of aggression: a univariate and multivariate genetic analysis.

Previous behaviour genetic studies of aggression have yielded inconsistent results: reported heritabilities for different types of aggressive behaviour ranging from 0 to 0.98. In the present study, 247 adult twin pairs (183 MZ pairs; 64 same-sex DZ pairs) were administered seven self-report questionnaires which yielded 18 measures of aggression. Univariate genetic analyses showed moderate to high heritabilities for 14 of these 18 measures and for a general aggression factor and three correlated aggression factors extracted from the measures. Multivariate genetic analyses showed sizeable genetic correlations between the different dimensions of aggression. Thus, individual differences in many types of aggressive behaviour are attributable to some extent to genetic factors and there is considerable overlap between the genes that operate on different types of aggressive behaviour.

Individual differences in multiple dimensions of aggression: a univariate and multivariate genetic analysis

AbstractPrevious behaviour genetic studies of aggression have yielded inconsistent results: reported heritabilities for different types of aggressive behaviour ranging from 0 to 0.98. In the present study, 247 adult twin pairs (183 MZ pairs; 64 same-sex DZ pairs) were administered seven self-report questionnaires which yielded 18 measures of aggression. Univariate genetic analyses showed moderate to high heritabilities for 14 of these 18 measures and for a general aggression factor and three correlated aggression factors extracted from the measures. Multivariate genetic analyses showed sizeable genetic correlations between the different dimensions of aggression. Thus, individual differences in many types of aggressive behaviour are attributable to some extent to genetic factors and there is considerable overlap between the genes that operate on different types of aggressive behaviour.

A note on issues in meta-analysis for behavioral genetic studies using categorical phenotypes.

Meta-analysis of behavioral genetic studies would provide (i) tighter confidence intervals around parameter estimates, (ii) clarification of apparently discrepant study findings, and (iii) a mechanism for analyzing systematic causes of between-study differences. We examined some key issues that arise in the meta-analysis of categorical phenotypes. Data were simulated under a multifactorial threshold model that assumed an underlying normal liability distribution, and summary statistics (probandwise concordance rate, recurrence risk ratio, odds ratio, kappa) compared for given values of the liability correlation between relatives and given population prevalence. Although the odds ratio and kappa statistic performed well at moderate to high values of the population prevalence (15-50%), at low values all of these statistics were sensitive to overall prevalence. In cases where the assumption of a multifactorial threshold model is reasonable, direct estimation of genetic and environmental parameters from the summary statistics from all studies appears to be a preferable strategy. For cases where data from non-randomly ascertained samples are used, the impact of misspecification of the model for ascertainment was examined. For some parameter values, such misspecifications led to quite serious biases to estimates of genetic and environmental parameters. These biases varied in complex ways as a function of research design and of the true causes of variation in the population, so that the same misspecification could lead to an overestimate of the importance of genetic influences in twin data but an underestimation in adoption data or to an overestimate of the importance of genetic effects from twin data if shared environmental as well as genetic influences were simulated but an underestimate of genetic effects if shared environmental effects were assumed unimportant. These complexities emphasize the importance of being sensitive to the effects of misspecifying ascertainment corrections in any meta-analysis of behavioral genetic data.

Implications of the restricted range of family environments for estimates of heritability and nonshared environment in behavior-genetic adoption studies.

Implications of the restricted range of family environments for estimates of heritability and nonshared environment in behavior-genetic adoption studies.

Behavioral genetics as a tool for developmental psychology: anxiety and depression in children and adolescents.

Over the past decade there has been a huge increase in the number of behavioral genetic studies looking into anxiety and depression in children and adolescents. There are now enough data in this area to make a review of the results useful. This paper begins with an outline of the methods used in such research and moves on to review the results in extant studies. Overall, these studies indicate modest to moderate genetic influence on both anxiety and depression. However, behavioral genetic methods are also paramount for exploring environmental influences in addition to genetic influences. Shared environment (that which makes family members resemble one another) is rarely identified in adult studies of personality or psychopathology and does not appear to be a significant influence for depression but it is for anxiety. Nonshared environment, which makes family members differ from one another, is found to be a significant influence for both anxiety and depression. Patterns within these results due to rater effects, age effects, sex effects, the precise phenotype measured, and the study design are explored.

Contrast effects in Buss and Plomin’s EAS questionnaire: a behavioral-genetic study on early developing personality traits assessed through parental ratings

Temperament was assessed through separate mother and father ratings in a sample of 354 German mono- and dizygotic twin pairs aged 2–14 years. We administered the EAS Temperament Survey (Buss and Plomin, 1984), measuring Emotionality, Activity, Sociability and Shyness to investigate the usefulness of the 20-item inventory for behavior genetic studies of early developing personality traits in children. Most of the studies that report zero or even negative correlations for dizygotic twins in parental ratings assessed temperament in very young children only. The present study covered a larger age range to examine whether this pattern of results was also found in parental ratings of older children when the same inventory was used.Our findings clearly demonstrate that similarities of dizygotic twins were substantially less than half the MZ twin correlations. For all EAS dimensions except Emotionality, DZ twin correlations were close to zero or negative. Hardly any systematic correspondence emerged between age and twin similarity. The design of our study made it possible to analyse contrast effects, which might be responsible for DZ twin dissimilarity, within and across raters. We found evidence that contrast effects were not only observed in separate mother or father ratings but were also found when cross-correlations were analysed.Thediscussion focuses on the nature of contrast effects in parental rating data and the usefulness of parental ratings in temperament questionnaires given the growing evidence that true similarities of dizygotic twins are underestimated.

Socialization of Emotion and Children's Emotional Competence: Variations Are the Theme

Pelaez-Nogueras, M., Field, T., Cigales, M., Gonzalez, A., & Clasky, S. (1994). Infants of mothers show less depressed behavior with their nursery teachers. Infant Mental Health Journal, 15, 358-367. Plomin, R., Owen, M. J., & McGuffin, P. (1994, June 17). The genetic basis of complex human behaviors. Science, 264, 1733-1739. Reiss, D. (1997). Mechanisms linking genetic and social influences in adolescent development: Beginning a collaborative search. Current Directions in Psychological Science, 6, 100-105. Rovee-Collier, C. (1993). The capacity for long-term memory in infancy. CurrentDirections in Psychological Science, 2, 130-135. Saudino, K. J. (1997). Moving beyond the heritability question: New directions in behavioral genetic studies of personality. Current Directions in Psychological Science, 6, 86-90. Scarr, S. (1992). Developmental theories forthe 1990s: Development and individual differences. Child Development, 63, 1-19. Stocker, C., & Dunn, J. (1990). Sibling relationships in childhood: Links with friendships and peer relationships. British Journal of Developmental Psychology, 8, 227-244.

Developmental neuropsychology: A behavioral genetic perspective

The study of developmental behavioral genetics has become increasingly popular over the last several decades as the study of biological influences on behavior has become more accepted in psychology in general. This special issue of Developmental Neuropsychology is a testament to the fact that there has been an increase in the number of researchers who are interested in the study of genetic influences on behaviors from a neuropsychological perspective. The inclusion of a behavior genetic perspective in neuropsychological research allows a more in‐depth exploration of the ways in which both heritable and environmental influences affect basic biological behaviors, which opens the way for a greater understanding of the gene‐brain‐behavior pathway. The articles that comprise this special issue take a neuropsychological perspective as they explore a variety of topics across a range of ages. Thus, this issue provides a unique forum for a discussion about the behavior genetic and neuropsychological aspects of development.

From the cognitive to the biological: A sketch of Arthur Jensen's contributions to the study of g

One of Arthur Jensen's major contributions to the field of individual differences has been his investigations of the nature of g. Starting with relatively small-scale reaction time studies. Jensen and his colleagues' research on g rapidly evolved to include multiple measures of the speed with which individuals could process different kinds of information. The results of these studies, combined with Jensen's interest in the biological basis of g, led to behavioral genetic studies of intelligence and speed-of-processing, and, most recently to the study and identification of a number of biological/physiological correlates of g. This sketch provides a brief overview of these aspects of Jensen's lifework.

Genotypic differences between C57BL/6 and A inbred mice in anxiolytic and sedative actions of diazepam.

The role of genotype in susceptibility to the behavioral actions of benzodiazepines is not well characterized. To develop a model for such studies, we have characterized the anxiolytic and sedative activities of diazepam in C57BL/6J and A/J inbred mice. C57BL/6J mice were more responsive than A/J mice to diazepam-induced anxiolytic-like activity in the mirrored chamber aversion assay and the elevated plus-maze assay. Basal activity of the two strains did not differ in either assay. In contrast, the two strains were equally responsive to the anxiolytic effects of the 5-HT1A receptor partial agonist, buspirone. C57BL/6J mice were also more susceptible to the sedative effects of diazepam than were A/J mice. Flumazenil blocked the effects of diazepam in these behavioral assays. Measurement of diazepam and nordiazepam in blood and brain suggested that the response differences are of a pharmacodynamic rather than a pharmacokinetic nature. Taken together, these findings indicate that C57BL/6J and A/J mice provide a valuable tool for behavioral genetic studies of the mechanisms underlying the pharmacological actions of benzodiazepines.

Cross-Cultural Assessment of the Five-Factor Model

The five-factor model (FFM) is a representation of the patterns of covariation of personality traits in terms of five broad factors. The Revised NEO Personality Inventory, a questionnaire measure of the FFM, has recently been translated into a number of different languages, permitting tests of its cross-cultural replicability. Data from Filipino and French translations are presented, showing clear and detailed replication of the American normative factor structure when targeted rotation is used. Results from these and other cross-cultural and behavior genetic studies suggest that the FFM is a biologically based human universal. Applications of trait psychology in clinical, educational, and organizational settings may prove generalizable across cultures, and cross-cultural psychologists can profitably explore the expression of the same personality traits in different cultural contexts.

A Behavioural Genetic Perspective on Close Relationships

This paper examines how genetic, shared environment, and nonshared environment influence individual differences in close relationships. First, a brief explanation of behavioural genetic methods is given. Next, we review behavioural genetic studies of the close relationships in which people are typically involved (parent-child, sibling, friend, and spouse). Many of the studies reviewed indicate a modest to moderate role for genetic factors. This suggests that genetic make-up can affect the nature of close relationships. It also implies that genetic factors may be involved in the influence of close relationships on individual adaptation. Behavioural genetic research has begun to show that this is the case. Close relationships may be especially important sources of nonshared environment. Behavioural genetic research consistently shows that environmental factors that have a functional effect on psychological traits work to make siblings in the same family different from one another rather than similar. Attempts to pinpoint specific aspects of the nonshared environment are under way. Parent-child relationships have been systematically explored, and found not to play an important role in nonshared environment. This leaves open the possibility that extrafamilial relationships, in particular friendships, may be important contributors to the nonshared environment.

Moving Beyond the Heritability Question

50% of the variability of personal ity within a population. The find ing of genetic influences on person ality has been replicated across American, Australian, British, Finnish, Swedish, and Russian cul tures. However, the conclusion that individual differences in per sonality are, in part, due to genetic factors is just the beginning of the story. Behavioral genetics has much more to offer to the study of personality than heritability esti mates, and in this article, I describe three exciting new directions that behavioral genetic studies of per sonality are taking. Although basic behavioral genetic terms are de fined, details of the theory and methods cannot be described in

Continuity and change in children's social maladjustment: A developmental behavior genetic study.

Continuity and change in children's social maladjustment: A developmental behavior genetic study.