Prosocial behavior from early to middle childhood: genetic and environmental influences on stability and change

Prosocial behavior is important for the functioning of society. This study investigates the extent to which environment shared by family members, nonshared environment, and genetics account for children's prosocial behavior. The prosocial behavior of twins (9,424 pairs) was rated by their parents at the ages of 2, 3, 4, and 7 and by their teachers at age 7. For parent ratings, shared environmental effects decreased from .47 on average at age 2 to .03 at age 7, and genetic effects increased from .32 on average to .61. The finding of weak shared environmental effects and large heritability at age 7 was largely confirmed through the use of teacher ratings. Using longitudinal genetic analyses, the authors conclude that genetic effects account for both change and continuity in prosocial behavior and nonshared environment contributes mainly to change.     

Oxytocin Receptor (OXTR) Single Nucleotide Polymorphisms Indirectly Predict Prosocial Behavior Through Perspective Taking and Empathic Concern

Engaging in prosocial behavior can provide positive outcomes for self and others. Prosocial tendencies contribute to the propensity to engage in prosocial behavior. The oxytocin receptor gene (OXTR) has also been associated with prosocial tendencies and behaviors. There has been little research, however, investigating whether the relationship between OXTR and prosocial behaviors is mediated by prosocial tendencies. This relationship may also vary among different types of prosocial behavior. The current study examines the relationship between OXTR, gender, prosocial tendencies, and both altruistic and public prosocial behavior endorsement. Students at a midwestern university (N = 398; 89.2% Caucasian; M_age = 20.76; 26.6% male) provided self‐report measures of prosocial tendencies and behaviors and buccal cells for genotyping OXTR polymorphisms. Results indicated that OXTR single nucleotide polymorphism (SNP) rs2268498 genotype significantly predicted empathic concern, whereas gender moderated the association between several other OXTR SNPs and prosocial tendencies. Increased prosocial tendencies predicted increased altruistic prosocial behavior endorsement and decreased public prosocial behavior endorsement. Our findings suggest an association between genetic variation in OXTR and endorsement of prosocial behavior indirectly through prosocial tendencies, and that the pathway is dependent on the type of prosocial behavior and gender.     

Self‐Protective Altruism

Prosocial behavior accentuates the tension between two conflicting human motivations, self‐interest and belongingness. Responding to the needs of others may compromise self‐interest. Acting callously, however, may lead to social disproval. These antagonistic responses are existentially meaningful as belongingness and self‐esteem have been found to regulate death anxiety. In this paper I critically examine three possible hypotheses concerning the tension between egotism and prosociality from a terror management perspective. The first hypothesis, the carpe diem hypothesis, suggests that when death is salient egotistic self‐interest overrides other‐oriented responses. The second hypothesis, the norm salience hypothesis, suggests that when death is salient people will respond according to the momentarily accessible social norm. The third hypothesis, the self‐protective altruism hypothesis, argues that when the prosocial cause reminds people of their fragile, mortal nature people will turn away from helping when death is salient, but when the prosocial cause is benign death salience will increase prosocial responding.     

Genetic and environmental links between motor activity level and attention problems in early childhood

Cross‐lagged biometric models were used to examine genetic and environmental links between actigraph‐assessed motor activity level (AL) and parent‐rated attention problems (AP) in 314 same‐sex twin pairs (MZ = 145, DZ = 169) at ages 2 and 3 years. At both ages, genetic correlations between AL and AP were moderate (r_a2 = .35; r_a3 = .39) indicating both overlap and specificity in genetic effects across the two domains. Within‐ and across‐age phenotypic associations between AL and AP were entirely due to overlapping genetic influences. There was a unidirectional effect of AL at age 2 predicting later AP. For AP, genetic and environmental influences from age 2 were transmitted to age 3 via stability effects and from AL. For AL, across‐age effects were transmitted only via stability. These results suggest that overactivity in late infancy may impact the later development of problems related to inattention, and that genetic factors explain the association between the two domains.     

Difficult temperament and negative parenting in early childhood: a genetically informed cross‐lagged analysis

A genetically informed longitudinal cross‐lagged model was applied to twin data to explore etiological links between difficult temperament and negative parenting in early childhood. The sample comprised 313 monozygotic (MZ) and dizygotic (DZ) twin pairs. Difficult temperament and negative parenting were assessed at ages 2 and 3 using parent ratings. Both constructs were interrelated within and across age (rs .34–.47) and showed substantial stability (rs .65–.68). Difficult temperament and negative parenting were influenced by genetic and environmental factors at ages 2 and 3. The genetic and nonshared environmental correlations (rs .21–.76) at both ages suggest overlap at the level of etiology between the phenotypes. Significant bidirectional associations between difficult temperament and negative parenting were found. The cross‐lagged association from difficult temperament at age 2 to negative parenting at age 3 and from negative parenting at age 2 and difficult temperament at age 3 were due to genetic, shared environmental, and nonshared environmental factors. Substantial novel genetic and nonshared environmental influences emerged at age 3 and suggest change in the etiology of these constructs over time.     

A Twin Study of the Relationships among Inattention, Hyperactivity/Impulsivity and Sluggish Cognitive Tempo Problems

We investigated the etiological relationships between the three ADHD dimensions of Inattentive Problems (INP), Hyperactivity-Impulsivity Problems (HIP) and Sluggish Cognitive Tempo (SCT) as measured by the CBCL 6–18 questionnaire. Multivariate models were applied to 398 twin pairs (374 boys and 422 girls) aged 8 to 17 years (M?=?13.06, SD?=?2.59) belonging to the population-based Italian Twin Registry. The INP, HIP and SCT problem scores were moderately-to-substantially (range 0.29–0.47) intercorrelated. The best fitting model showed that these 3 dimensions are correlated both at the genetic (correlations’ range: 0.65–0.83) and the environmental (correlations: 0.29 and 0.44) levels, but they are also distinct. While SCT showed moderate heritability and large non-shared environmental influences, variance for both INP and HIP was substantially explained by genetic influences. We also found evidence of negative sibling interaction for INP, implying that a given behavior in one twin leads to an opposite behavior in the co-twin. Our results support at the etiological level the findings of previous psychometric and longitudinal studies of ADHD, which yielded evidence of the 3 distinct—albeit correlated—problem dimensions of inattentiveness, hyperactivity-impulsivity, and sluggish cognitive tempo.     

Beyond Heritability: Twin Studies in Behavioral Research

ABSTRACT— The heritability of human behavioral traits is now well established, due in large measure to classical twin studies. We see little need for further studies of the heritability of individual traits in behavioral science, but the twin study is far from having outlived its usefulness. The existence of pervasive familial influences on behavior means that selection bias is always a concern in any study of the causal effects of environmental circumstances. Twin samples continue to provide new opportunities to identify causal effects with appropriate genetic and shared environmental controls. We discuss environmental studies of discordant twin pairs and twin studies of genetic and environmental transactions in this context.     

Investigating cognitive transfer within the framework of music practice: genetic pleiotropy rather than causality

The idea of far transfer effects in the cognitive sciences has received much attention in recent years. One domain where far transfer effects have frequently been reported is music education, with the prevailing idea that music practice entails an increase in cognitive ability (IQ). While cross‐sectional studies consistently find significant associations between music practice and IQ, randomized controlled trials, however, report mixed results. An alternative to the hypothesis of cognitive transfer effects is that some underlying factors, such as shared genes, influence practice behaviour and IQ causing associations on the phenotypic level. Here we explored the hypothesis of far transfer within the framework of music practice. A co‐twin control design combined with classical twin‐modelling based on a sample of more than 10,500 twins was used to explore causal associations between music practice and IQ as well as underlying genetic and environmental influences. As expected, phenotypic associations were moderate (r = 0.11 and r = 0.10 for males and females, respectively). However, the relationship disappeared when controlling for genetic and shared environmental influences using the co‐twin control method, indicating that a highly practiced twin did not have higher IQ than the untrained co‐twin. In line with that finding, the relationship between practice and IQ was mostly due to shared genetic influences. Findings strongly suggest that associations between music practice and IQ in the general population are non‐causal in nature. The implications of the present findings for research on plasticity, modularity, and transfer are discussed.     

Identity, Reasoning, and Emotion: An Empirical Comparison of Three Sources of Moral Motivation

Prior research on moral motivation has primarily emphasized moral reasoning and moral emotion; however, identity may also play an important role. Therefore, the purpose of the present study was to examine the relative importance of prosocial identity, prosocial moral reasoning, and empathy in predicting prosocial behavior. The sample included 91 university students, ages 19–35 years (M=21.89; SD=3.01; 80% European American; 65% female). Prosocial identity and empathy, but not prosocial moral reasoning, were positively associated with overall prosocial behavior. Exploratory analyses examined how these three sources of prosocial motivation differentially related to six forms of prosocial behavior. Results suggest the importance of considering the roles of all three sources of moral motivation.     

A Multimethodological Study of Preschoolers' Preferences for Aggressive Television and Video Games

The association between aggressive media and related behavior is complicated, and the role of underlying genetics has not been adequately explored. A better understanding of the role of genetics on the relationship between aggressive media and behavior, especially in young children, is critical. Using a twin/triplets sample (N = 184 children), the authors investigated the association between preschoolers' preferred media choices and their aggressive behaviors. A multimeasure methodology was utilized, examining children's reports of their preferred media games and shows, observed child negativity and aggression in the lab, and parent reports of their own and their children's aggressive behaviors. The results demonstrated a significant relationship between maternal aggression and parent-reported child aggression, especially for boys. Genetic analyses demonstrated significant heritability for children's parent-reported aggressive behaviors, supporting the biological basis of aggression, but not for media aggression preferences. Controlling for genetics, the authors found that the association between media preferences and aggressive behavior may be genetic in origin. These results emphasize the importance of considering shared genetics underlying the relationship between children's aggressive behaviors and their media preferences, as well as environmental influences. By examining preschoolers, the present study provides insight into the importance of media influences in children younger than those previously studied.     

What Causes Internalising Traits and Autistic Traits to Co-occur in Adolescence? A Community-Based Twin Study

Autism shows a high degree of comorbidity with anxiety disorders. Adolescence is a time of increased stress and vulnerability to internalising problems. This study addresses for the first time the degree of genetic and environmental overlap between autistic traits (total measure and subscales) and internalising traits in a community-based adolescent twin sample. Parents of 12-14-year-old twins (N?=?3,232 pairs; 3,460 males, 3,004 females) reported on the twins’ internalising and autistic traits. Autistic trait subscales were created using principal component analysis. Bivariate twin model-fitting was conducted. Autistic and internalising traits correlated moderately (r?=?0.30). Genetic influences on individual traits were substantial but genetic overlap between traits was moderate (genetic correlation: males?=?0.30, females?=?0.12). Shared environmental influences were low for internalising traits and moderate for autistic traits, and showed considerable overlap (shared environmental correlation: males?=?0.53, females?=?1). Nonshared environmental influences were moderate for internalising traits and low for autistic traits and showed low overlap. A multiple component solution was found for autistic traits and of the derived subscales, autistic-like ‘Social Unease’ showed the most phenotypic and genetic overlap with internalising traits.     

Parental play styles and sibling interaction during a problem‐solving task

Associations between parental play styles and sibling interaction were investigated in 30 same‐sex preschool‐ and school‐aged sibling dyads (first‐borns were 4–9 years, M=6.6 years; second‐borns were 2–7 years, M=4.2 years), divided into older and younger sibling groups. Participants completed puzzles under three conditions: (a) siblings alone, (b) together with mother, and (c) together with father. Prosocial and agonistic sibling‐directed behaviors and positive and negative parent–child behaviors were coded. Siblings engaged in both more prosocial and agonistic interactions when alone than with either parent; there were no differences in sibling interactions in the mother versus father episodes. Paternal negative behavior was associated with sibling agonistic behavior when the children were alone, indicating second‐order effects, however, mother–child and sibling interactions were not significantly associated. Nevertheless, reciprocity in positive and negative behaviors directed by children to parents and vice versa was evident, demonstrating synchrony in patterns of exchanges. The findings underscore the necessity of studying both parents in order to understand more fully the dynamics involved in family relationships. Copyright © 1999 John Wiley & Sons, Ltd.     

Genetic and Environmental Influences on Media Use and Communication Behaviors

A great deal of scholarly work has explored the motivations behind media consumption and other various communication traits. However, little research has investigated the sources of these motivations and virtually no research considers their potential genetic underpinnings. Drawing on the field of behavior genetics, we use a classical twin design study to examine the genetic and environmental influences on nine communication behaviors. Our findings indicate a substantial portion of the total variance in media habits can be attributed to genes, as much as one‐third of the variance in some instances. Mass communication scholars would benefit by paying closer attention to heritability when thinking about the causes as well as the consequences of media traits in contemporary society.     

From self‐disclosure to prosocial behaviour: Feedback as a moderator

Prosocial behaviours and their correlates have been extensively studied; however, few studies have examined the linkage between self‐disclosure and prosocial behaviours. Three studies were conducted aimed at examining the relationship between self‐disclosure and prosocial tendencies, as well as the moderating role of feedback from the help provider's perspective. We hypothesized that participants' self‐disclosure was positively associated with his/her prosocial tendencies and that this association would be moderated by feedback received. The results generally support our hypotheses, and reveal that participants with higher levels of self‐disclosure tend to exhibit more prosocial tendencies (Studies 1 and 2), but this association was only true for those participants that received self‐disclosure feedback (Study 3). The present study suggests that, other than self‐disclosure, reciprocal feedback also plays an important role in promoting prosocial behaviours.     

Home environmental influences on children's language and reading skills in a genetically sensitive design: Are socioeconomic status and home literacy environment environmental mediators and moderators?

This twin study examined how family socioeconomic status (SES) and home literacy environment (HLE) contributes to Chinese language and reading skills. It included 312 Chinese twin pairs aged 3 to 11. Children were individually administered tasks of Chinese word reading, receptive vocabulary and reading‐related cognitive skills, and nonverbal reasoning ability. Information on home environment was collected through parent‐reported questionnaires. Results showed that SES and HLE mediated shared environmental influences but did not moderate genetic influences on general language and reading abilities. Also, SES and HLE mediated shared environmental contributions to receptive vocabulary and syllable and rhyme awareness, but not orthographic skills. The findings of this study add to past twin studies that focused on alphabetic languages, suggesting that these links could be universal across languages. They also extend existing findings on SES and HLE's contributions to reading‐related cognitive skills.     

“Principles in his nature which interest him in the fortune of others…”: The heritability of empathic concern for others1

The present research was conducted to explore genetic influences on empathic concern for others. First, an index of empathic concern was created by combining relevant items from Gough's Adjective Check List (ACL). This index was validated by correlating scores of 88 undergraduates on the index with their scores on a self-report measure of empathy, which has been related to prosocial behavior. Correlations were sufficiently high to accept the validity of the index. Next, previously collected ACL responses of 114 monozygotic (MZ) and 116 dizygotic (DZ) twins were reanalyzed in order to create an empathic concern score for each twin. The twins were middle-aged males initially raised together but living apart at the time they completed the ACL. Comparison of intraclass correlations for MZ and DZ twins revealed, as predicted by the genetic hypothesis, significant (p < .005) heritability in empathic concern scores. This finding suggests that there may, indeed, be a genetic influence on individual differences in empathic concern for others. Some limitations of the present data are also considered. How selfish soever man may be supposed, there are evidently some principles in his nature which interest him in the fortune of others, and render their happiness necessary to him.     

The Etiology of Behavior Problems in 7-Year-Old Twins: Substantial Genetic Influence and Negligible Shared Environmental Influence for Parent Ratings and Ratings by Same and Different Teachers

Parent ratings of behavior problems in childhood show substantial genetic influence and modest shared environmental influence. However, few studies have compared these results to teacher ratings and no previous studies have compared same-teacher ratings to different-teacher ratings. 3,714 7-year-old twin pairs in the Twins Early Development Study were rated by parents and teachers on the Strengths and Difficulties Questionnaire. Substantial heritability and negligible shared environmental influence were found for data from all three raters for total behavior problems, hyperactivity, prosocial behavior, peer problems, conduct problems, and emotional symptoms. Sex-limitation models revealed similar results for males and females, although there was some evidence for greater heritability for boys, especially when twins were rated by the same teacher.     

Attachment security,values, and prosocial attitudes

The objective of this study was to determine whether individuals with different attachment styles held different prosocial values and attitudes given their different models of self and of others. A sample of 717 university students completed the ECR ‐S (Experiences in Close Relationships‐Spanish) and the PVQ (Portrait Values Questionnaire), and evaluated different prosocial attitudes. The results showed that secure individuals reported higher scores on self‐transcendence and in the value self‐directions of the dimension openness to change , whereas insecure individuals had higher scores on conservation and self‐enhancement . No differences were found in the attitudes of individuals with different attachment styles. These findings show a link between the dimensions of the universal values theory, and the models of self and of others.     

Genetic overlap between ADHD symptoms and EEG theta power

Biological markers that are grounded in neuroscience may facilitate understanding of the pathophysiology of complex psychiatric disorders. One of the most consistent and robust neural abnormalities in attention deficit hyperactivity disorder (ADHD) is increased EEG power in the theta band at rest (4–8 Hz). The present study used a twin design to estimate the extent of genetic overlap between increased theta power and risk for ADHD in order to validate theta power as a marker of genetic risk for ADHD. At rest, EEG was measured in 30 monozygotic and dizygotic adolescent twin pairs concordant or discordant for high ADHD symptom scores and 37 monozygotic and dizygotic control twin pairs with low ADHD symptom scores. Structural equation modelling was used to estimate the heritability of theta power and partition the genetic and environmental contributions to the overlap between ADHD and theta power. A significant phenotypic correlation between ADHD symptoms and elevated theta power was found. Theta power demonstrated moderate to high heritability estimates (0.77) and moderate genetic correlations with ADHD (0.35) suggesting shared genetic influences. Increased theta power is a candidate biological marker of genetic risk for ADHD, which warrants further investigation of the neurobiological mechanisms that underlie the genetic relationship.     

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.