Genetic and environmental influences on aggression in 4- to 7-year-old twins

Aggressive behaviors of 38 twin pairs (21 monozygotic [MZ], 17 dizygotic [DZ]) between the ages of 4 and 7 years were assessed through mothers' ratings and observations in their homes. An observation checklist was developed in which mothers were asked to observe and report each child's specific aggressive behaviors for a total of 6 hours spread over 3 days. In particular the observations focused on the following behaviors: rejection, destructiveness, negativism, noncompliance, teasing, physical negative, insult, verbal threat, and yelling. Biometrical genetic analysis evidenced significant heritable influences on composite aggression scores in both the observation checklist and the mothers' ratings; heritability estimates varied from.24 to.94 depending on the aggression nieasnre used, with scores from the mothers' observations demonstrating smaller genetic effect than those of the parental ratings of the environmental sources of variance, within-family factors were far more important than the between-family ones. The results also yielded significant sex and zygosity differences for means of some of the specific aggressive behaviors, where males and DZ twins scored higher than females and MZ twins. It was suggested that future studies should include more detailed investigations of the context in which specific aggressive behaviors occur and the sources toward which they are directed in order to determine the extent to which different types of aggression may have different etiologies.     

Sex differences in genetic and environmental effects on aggression

The aim of the present study was to investigate the genetic and environmental factors influencing teacher and parental rated aggression in boys and girls, asking whether the magnitude of these effects is similar across rater and sex. The study is part of an ongoing nationwide twin‐family study of behavioral development and health habits carried out in Finland. The sample consisted of 1651 twin pairs (264 monozygotic male, 300 monozygotic female, 292 dizygotic male, 278 dizygotic female, and 517 dizygotic opposite‐sex twin pairs), representing subsets of five 11‐ to 12‐year‐old twin cohorts (b. 1983–1987). The data were collected using the teacher and parental rating forms of the Multidimensional Peer Nomination Inventory. Structural equation models of sex‐limitation assessed sex differences in genetic and environmental influences on aggression. The results suggested significant genetic, common environmental, and specific environmental effects on aggression in both boys and girls, but the best fitting model differed depending on the informant. For both ratings, boys showed lower levels of heritability and higher levels of common environment than girls. In addition, the teacher rating data also suggested the presence of either sex‐specific common environmental effects or sex‐specific genetic effects. Support is provided also for sibling contrast effects, either at the behavioral level or as a rater bias. Aggr. Behav. 29:55–68, 2003. © 2003 Wiley‐Liss, Inc.     

Genetic and environmental stability differs in reactive and proactive aggression

The aim of this study was to examine stability and change in genetic and environmental influences on reactive (impulsive and affective) and proactive (planned and instrumental) aggression from childhood to early adolescence. The sample was drawn from an ongoing longitudinal twin study of risk factors for antisocial behavior at the University of Southern California (USC). The twins were measured on two occasions: ages 9–10 years (N=1,241) and 11–14 years (N=874). Reactive and proactive aggressive behaviors were rated by parents. The stability in reactive aggression was due to genetic and nonshared environmental influences, whereas the continuity in proactive aggression was primarily genetically mediated. Change in both reactive and proactive aggression between the two occasions was mainly explained by nonshared environmental influences, although some evidence for new genetic variance at the second occasion was found for both forms of aggression. These results suggest that proactive and reactive aggression differ in their genetic and environmental stability, and provide further evidence for some distinction between reactive and proactive forms of aggression. Aggr. Behav. 35:437–452, 2009. © 2009 Wiley‐Liss, Inc.     

Proactive and reactive aggression in early adolescence as precursors to anti- and prosocial behavior in young adults

Three groups of adolescents who were 14 years old in 1974 were formed on the basis of peer nominations and teacher ratings in an ongoing longitudinal study: 1) reactively aggressive (REA) individuals who displayed reactive, that is, self-defensive aggression but not proactive aggression (43 boys, 35 girls); 2) proactively aggressive (PROA) individuals who attacked another person without a reason (56 boys, 35 girls); and 3) nonaggressive (NONA) individuals who were low in proactive and reactive aggression (48 boys, 45 girls). The groups were compared at ages 8, 14, and 27 in variables representing the constructs of a two-dimensional model of emotional and behavioral regulation. The REA Ss were characterized by higher self-control, especially constructiveness, at each age and better adult adjustment than the PROA Ss. The PROA males were prone to externalizing problems and criminality in adulthood, whereas the PROA females were prone to internalizing problems and neuroticism in adulthood. Both exhibited conduct problems in adolescence, and became heavy users of alcohol in adulthood. The PROA Ss had more children at age 27 than the other Ss. © 1996 Wiley-Liss, Inc.     

Predicting dating behavior from aggression and self‐perceived social status in adolescence

We investigated the longitudinal associations between self‐reported aggression, self‐perceived social status, and dating in adolescence using an intrasexual competition theoretical framework. Participants consisted of 536 students in Grade 9 (age 15), recruited from a community sample, who were assessed on a yearly basis until they were in Grade 11 (age 17). Adolescents self‐reported their use of direct and indirect aggression, social status, and number of dating partners. A cross‐lagged panel model that controlled for within‐time covariance and across‐time stability while examining cross‐lagged pathways was used to analyze the data. The findings revealed that direct aggression did not predict dating behavior and was negatively associated with self‐perceived social status in Grade 10. Self‐perceived social status in Grade 9 was positively associated with greater use of indirect aggression in Grade 10. Regarding dating, in Grade 9, self‐perceived social status positively predicted more dating partners the following year, while in Grade 10, it was higher levels of indirect aggression that predicted greater dating activity the following year. Overall, there were no significant sex differences in the model. The study supports the utility of evolutionary psychological theory in explaining peer aggression, and suggests that although social status can increase dating opportunities, as adolescents mature, indirect aggression becomes the most successful and strategic means of competing intrasexually and gaining mating advantages.

     

Associations of self‐esteem and temperament traits to self‐ and teacher‐reported social status among classmates

Hintsanen, M., Alatupa, S., Pullmann, H., Hirstiö‐Snellman, P. & Keltikangas‐Järvinen, L. (2010). Associations of self‐esteem and temperament traits to self‐ and teacher‐reported social status among classmates. Scandinavian Journal of Psychology 51, 488–494. The present study examined the validity of self‐ and teacher‐reported social status and its relations to self‐esteem and temperament in a geographically representative cohort of Finnish adolescents (N = 3941, mean age 15.1 years). High agreement was found between self‐ and teacher‐rated social status (r = 0.42). Different aspects of self‐esteem were differently related to social status. When other temperament and self‐esteem variables were included in the analyses, strongest predictor for self‐rated social status in both genders was social self‐esteem (p < 0.01) and for teacher‐rated social status general self‐esteem (p < 0.01). The strongest temperamental predictors of social status were lower inhibition in girls (p < 0.01, self‐ and teacher‐rated) and higher impulsivity (p < 0.01, self‐rated) and activity (p < 0.01, teacher‐rated) in boys. The present findings are consistent with the view that social functioning and peer relations are associated with individual differences in self‐concept and temperament dimensions.     

Continuity of aggression from childhood to early adulthood as a predictor of life outcomes: implications for the adolescent‐limited and life‐course‐persistent models

Using data from the Columbia County Longitudinal Study, a 40‐year longitudinal study following an entire county's population of third‐grade students from age 8 to 48, we examine questions about the long‐term consequences of aggressive and antisocial behavior in childhood, adolescence, and young adulthood. We found moderate levels of continuity of aggression from age 8 to 48 both for males and for females. Contrary to what some have proposed, we found that continuity of aggressiveness is owing to not only the high‐aggressive participants staying high but also owing to the low‐aggressive participants staying low. Compared with life‐course‐persistent low aggressives, we found that life‐course‐persistent high aggressives had consistently poorer outcomes across domains of life success, criminal behavior, and psychosocial functioning at age 48 (e.g., arrests, traffic violations, aggression toward spouse and divorces, depression, health, occupational and educational attainment). In contrast, adolescent‐limited and child‐limited aggressives did not differ from life‐course‐persistent low aggressives on the age 48 outcomes. Finally, the outcomes for late‐onset (early adulthood) aggressives were also problematic in some domains though not as problematic as those for life‐course‐persistent aggressives. Aggr. Behav. 35:136–149, 2009. © 2009 Wiley‐Liss, Inc.     

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.     

Sexual‐perception processes in acquaintance‐targeted sexual aggression

This study analyzes data from seven published studies to examine whether three performance‐based indices of men's misperception of women's sexual interest (MSI), derived from a self‐report questionnaire, are associated with sexual‐aggression history, rape‐supportive attitudes, sociosexuality, problem drinking, and self‐reported MSI. Almost 2000 undergraduate men judged the justifiability of a man's increasingly unwanted advances toward a woman on the Heterosocial Perception Survey‐Revised. Participants self‐reported any sexual‐aggression history, and some completed questionnaires assessing rape‐supportive attitudes, sociosexuality, problem drinking, and self‐reported MSI. A three‐parameter logistic function was fitted to participants’ justifiability ratings within a non‐linear mixed‐effects framework, which provided precise participant‐specific estimates of three sexual‐perception processes (baseline justifiability, bias, and sensitivity). Sexual‐aggression history and rape‐supportive attitudes predicted: (a) reduced sensitivity to women's affect; (b) more liberal biases, such that the woman's affect had to be more negative before justifiability ratings dropped substantially; and (c) greater baseline justifiability of continued advances after a positive response. Sexual‐aggression history and attitudes correlated more strongly with sensitivity than baseline justifiability; remaining variables showed the opposite pattern. This work underscores the role of sexual‐perception processes in sexual aggression and illustrates the derivation of performance‐based estimates of sexual‐perception processes from questionnaire responses.

     

Covariation of self‐ and other‐directed aggression among inpatient youth: continuity in the transition to treatment and shared risk factors

Although other‐ and self‐directed aggression covary in very high‐risk youth, these forms of aggression infrequently are studied simultaneously. Understanding better their covariation is an important task for improving services to high‐risk youth. In this study, data from the clinical records of 476 youth admitted to secure inpatient treatment were analyzed to examine relations among self‐ and other‐directed aggression exhibit before and during inpatient treatment. Analyses tested the hypotheses that self‐ and other‐directed aggression would tend to covary and display continuity from pre‐treatment to in‐treatment. Also tested were the hypotheses that youth with histories of co‐occurring self‐ and other‐directed aggression would show the highest levels of aggression during treatment and the greatest degree of personal and contextual risk on entering treatment. These hypotheses were largely supported. Exploratory analyses revealed interesting discontinuities in aggression (aggression emitted only before or during treatment) with critical implications for research and practice with youth receiving clinical care, especially those in institutional placements. Aggr. Behav. 36:205–217, 2010. © 2010 Wiley‐Liss, Inc.     

Effects of therapist‐worn protective equipment during functional analysis of aggression

The effects of therapist‐worn protective equipment (PE) on functional analysis (FA) outcomes for aggression were evaluated. Independent FAs with and without PE were conducted concurrently. Both FAs showed the same function of aggression for all participants. These results suggest that therapists may wear PE during FAs of aggression to reduce risk without altering the interpretation of the analysis.     

Social relationships,stressful life events,and self-reported physical health: Genetic and environmental influences

Abstract

This study investigates how the associations between self-reported health, stressful life events, and social relationships are mediated by genetic and environmental influences and how much of the variance in health is in common with variation in these psychosocial factors. The analyses are based on questionnaire data from 576 pairs of twins reared apart and twins reared together. The data revealed that for men environmental influences were solely important for variation in the psychosocial measures and were the primary mediators of the relationship with health. For women, on the other hand, a substantial portion of the variance in the psychosocial factors was due to genetic influences and these influences also contributed to the bulk of the correlations with health. The gender differences for the relationships and their mediation indicate that what should be regarded as a psychosocial factor of importance for health might differ between genders.     

The inter-relations of mother and father attachment, self-esteem and aggression during late adolescence

This study examined three models depicting the relations between mother and father attachment, self-esteem and aggression. A total of 385 participants (173 males and 212 females), aged from 18 to 20 years, completed self-rating questionnaires covering mother and father attachment, self-esteem and aggression. Results showed that self-esteem had additive and mediation effects on both the father attachment-aggression and mother attachment-aggression relationships, and also moderated the mother attachment-aggression relation. These findings are discussed in terms of different models for the inter-relations of mother and father attachment, self-esteem and aggression in late adolescence.