Parenting as a reaction evoked by children's genotype: a meta-analysis of children-as-twins studies.

Parenting has been extensively studied but mostly as a causal factor influencing child outcomes. The aim of the current article is to examine the child's side of the relationship by meta-analyzing studies which used quantitative genetic methods that provide leverage in understanding causality. A meta-analysis of 32 children-as-twins studies of parenting revealed a heritability estimate of 23%, thus indicating that genetically influenced behaviors of the child affect and shape parental behavior. The shared- and nonshared-environmental estimates, which amounted to 43% and 34%, respectively, indicate not only substantial consistency in parental behavior but also differential treatment within the family. Assessment method, age, and parenting dimension were found to be significant moderators of these influences. Our findings stress the importance of accounting for genotype-environment correlations in child-development studies and call into question previous research that interpreted correlational results in unidirectional terms with parenting as the sole causal factor.

Early concern and disregard for others as predictors of antisocial behavior.

BACKGROUND: Prediction of antisocial behavior is important, given its adverse impact on both the individuals engaging in antisocial behavior and society. Additional research identifying early predictors of future antisocial behavior, or antisocial propensity, is needed. The present study tested the hypothesis that both concern for others and active disregard for others in distress in toddlers and young children predict antisocial behavior during middle childhood and adolescence. METHODS: A representative sample of same-sex twins (N=956) recruited in Colorado was examined. Mother-rated and researcher-observed concern and disregard for others assessed at age 14-36 months were examined as predictors of parent- (age 4-12), teacher- (age 7-12), and self-reported (age 17) antisocial behavior. RESULTS: Observed disregard for others predicted antisocial behavior assessed by three different informants (parents, teachers, and self), including antisocial behavior assessed 14 years later. It also predicted a higher order antisocial behavior factor (ß=.58, p<.01) after controlling for observed concern for others. Mother-rated disregard for others predicted parent-reported antisocial behavior. Contrary to predictions, neither mother-rated nor observed concern for others inversely predicted antisocial behavior. RESULTS of twin analyses suggested that the covariation between observed disregard for others and antisocial behavior was due to shared environmental influences. CONCLUSIONS: Disregard for others in toddlerhood/early childhood is a strong predictor of antisocial behavior in middle childhood and adolescence. The results suggest the potential need for early assessment of disregard for others and the development of potential interventions.

Environmental contributions to preschoolers' semantic fluency.

Semantic fluency was examined in Hebrew-speaking 5-year-old monozygotic and dizygotic twins (N = 396, 198 pairs), 22% of them with mother-reported speech-related problems. There were positive correlations of similar magnitudes among monozygotic, same-sex dizygotic, and opposite-sex dizygotic twins. Analyses showed no genetic effects, alongside significant shared (39%) and non-shared environmental (61%) effects on fluency scores. The presence of speech-related problems in one twin affected the fluency score of the co-twin. A multivariate regression analysis revealed that parental education and length of stay at daycare significantly predicted fluency scores. We suggest that semantic fluency performance is highly affected by environmental factors at age 5 although genetic effects might emerge later on.

Gene-environment correlation in developmental psychopathology.

Modern research acknowledges that psychopathology and individual differences in normal development are the joint products of both biological and social influences. Although there have been numerous publications on Gene × Environment interactions in the past decade, gene-environment correlation is another important form of gene-environment interplay that has received less attention. This Special Section demonstrates, using a range of methodological approaches, the importance of gene-environment correlation in developmental psychopathology. Several types of gene-environment correlation are described, including passive, evocative, and active. Other studies highlight the potential for gene-environment correlation to obscure associations between risk exposures and child psychopathology. Future directions for gene-environment correlation research are discussed.

Boys' serotonin transporter genotype affects maternal behavior through self-control: a case of evocative gene-environment correlation.

Self-control, involving processes such as delaying gratification, concentrating, planning, following instructions, and adapting emotions and behavior to situational requirements and social norms, may have a profound impact on children's adjustment. The importance of self-control suggests that parents are likely to modify their parenting based on children's ability for self-control. We study the effect of children's self-control, a trait partially molded by genetics, on their mothers' parenting, a process of evocative gene-environment correlation. Israeli 3.5-year-old twins (N = 320) participated in a lab session in which their mothers' parenting was observed. DNA was available from most children (N = 228). Mothers described children's self-control in a questionnaire. Boys were lower in self-control and received less positive parenting from their mothers, in comparison with girls. For boys, and not for girls, the serotonin transporter linked polymorphic region gene predicted mothers' levels of positive parenting, an effect mediated by boys' self-control. The implications of this evocative gene-environment correlation and the observed sex differences are discussed.

The Longitudinal Israeli Study of Twins (LIST)-an integrative view of social development.

The Longitudinal Israeli Study of Twins (LIST) is a social developmental study, which implements social-developmental, molecular genetic, epigenetic, and behavioral genetic methods to advance knowledge on the development of individual differences in social behavior. Twins are followed from the age of three and both observational and parental-questionnaire data are collected on their empathy, temperament, and pro-social behavior. The parenting styles of parents are also evaluated using self-reports and observations and DNA samples are collected from parents and twins. In the current paper, we provide a review of our recent work and discuss the future aims of the LIST.

Brief report: early adolescents' value development at war time.

Values are considered relatively stable individual characteristics, and there is little research to date on the conditions that underlie value-priorities change. This small-scale short-term longitudinal study tested whether a major life event of war changes the priority that early adolescents assign to values. Thirty-nine Israeli adolescents completed the Schwartz Values Survey on four occasions-at the beginning, middle, and end of the 2006 Israeli-Lebanese war during which their hometown was bombed. As hypothesized, anxiety-based values of tradition, power, and security increased in importance, while conformity values decreased in importance. Anxiety-free values of benevolence, universalism, self-direction, stimulation, and hedonism decreased in importance. Achievement values decreased and then increased in importance. Despite methodological limitations, the findings demonstrate that value development, at least during early adolescence, can take place rather quickly under circumstances of major traumatic events such as war.

The contributions of oxytocin and vasopressin pathway genes to human behavior.

Arginine vasopressin (AVP) and oxytocin (OXT) are social hormones and mediate affiliative behaviors in mammals and as recently demonstrated, also in humans. There is intense interest in how these simple nonapeptides mediate normal and abnormal behavior, especially regarding disorders of the social brain such as autism that are characterized by deficits in social communication and social skills. The current review examines in detail the behavioral genetics of the first level of human AVP-OXT pathway genes including arginine vasopressin 1a receptor (AVPR1a), oxytocin receptor (OXTR), AVP (AVP-neurophysin II [NPII]) and OXT (OXT neurophysin I [NPI]), oxytocinase/vasopressinase (LNPEP), ADP-ribosyl cyclase (CD38) and arginine vasopressin 1b receptor (AVPR1b). Wherever possible we discuss evidence from a variety of research tracks including molecular genetics, imaging genomics, pharmacology and endocrinology that support the conclusions drawn from association studies of social phenotypes and detail how common polymorphisms in AVP-OXT pathway genes contribute to the behavioral hard wiring that enables individual Homo sapiens to interact successfully with conspecifics. This article is part of a Special Issue entitled Oxytocin, Vasopressin, and Social Behavior.

Human maternal behaviour is associated with arginine vasopressin receptor 1A gene.

Parenting is one of the main influences on children's early development, and yet its underlying genetic mechanisms have only recently begun to be explored, with many studies neglecting to control for possible child effects. This study focuses on maternal behaviour and on an allele at the RS3 promoter region of the arginine vasopressin receptor 1A (AVPR1A) gene, previously associated with autism and with higher amygdala activation in a face-matching task. Mothers were observed during a free-play session with each of their 3.5-year-old twins. Multilevel regression analyses revealed that mothers who are carriers of the AVPR1A RS3 allele tend to show less structuring and support throughout the interaction independent of the child's sex and RS3 genotype. This finding advances our understanding of the genetic influences on human maternal behaviour.

Value differentiation in adolescence: the role of age and cultural complexity.

Living in complex social worlds, individuals encounter discordant values across life contexts, potentially resulting in different importance of values across contexts. Value differentiation is defined here as the degree to which values receive different importance depending on the context in which they are considered. Early and mid-adolescents (N = 3,497; M = 11.45 years, SD = 0.87 and M = 16.10 years, SD = 0.84, respectively) from 4 cultural groups (majority and former Soviet Union immigrants in Israel and Germany) rated their values in 3 contexts (family, school, and country). Value differentiation varied across individuals. Early adolescents showed lower value differentiation than mid-adolescents. Immigrant (especially first generation) adolescents, showed higher value differentiation than majority adolescents, reflecting the complex social reality they face while negotiating cultures.

Heritability of children's prosocial behavior and differential susceptibility to parenting by variation in the dopamine receptor D4 gene.

Theoretical considerations and new empirical evidence suggest that children's development cannot simply be explained by either genes or environment but that their interaction is important to understanding child behavior. In particular, a genetic polymorphism, the exon III repeat region of the dopamine receptor D4, has been the focus of interest regarding differential susceptibility to parental influence. To study environmental and genetic influences on children's prosocial behavior, 168 twin pairs (mean age = 44 months) participated in an experiment that assessed prosocial behavior via three measures: compliant prosocial behavior elicited in response to social requests, self-initiated prosocial behavior enacted voluntarily, and mothers' rating of children's behavior. Genetic effects accounted for 34% to 53% of the variance in prosocial behavior. The rest of the variance was accounted for by nonshared environment and error. Parenting measures of maternal positivity, negativity, and unexplained punishment did not correlate significantly with children's prosocial behavior. However, when parenting was stratified by presence or absence of the child's dopamine receptor D4 7-repeat allele in an overlapping sample of 167 children to model differential susceptibility to parental influence, a richer picture emerged. Positive parenting related meaningfully to mother-rated prosocial behavior, and unexplained punishment related positively to self-initiated prosocial behavior, but only among children carrying the 7-repeat allele. The findings demonstrate that a molecular genetic strategy, based on genotyping of common polymorphisms and combined with a classic twin approach, provides a richer description of how genes and environment interact to shape children's behavior, and allows for the identification of differential sensitivity to parental influence.

The developmental origins of a disposition toward empathy: Genetic and environmental contributions.

The authors investigated the development of a disposition toward empathy and its genetic and environmental origins. Young twins' (N = 409 pairs) cognitive (hypothesis testing) and affective (empathic concern) empathy and prosocial behavior in response to simulated pain by mothers and examiners were observed at multiple time points. Children's mean level of empathy and prosociality increased from 14 to 36 months. Positive concurrent and longitudinal correlations indicated that empathy was a relatively stable disposition, generalizing across ages, across its affective and cognitive components, and across mother and examiner. Multivariate genetic analyses showed that genetic effects increased, and that shared environmental effects decreased, with age. Genetic effects contributed to both change and continuity in children's empathy, whereas shared environmental effects contributed to stability and nonshared environmental effects contributed to change. Empathy was associated with prosocial behavior, and this relationship was mainly due to environmental effects.

Values as protective factors against violent behavior in Jewish and Arab high schools in Israel.

This study tested the hypothesis that values, abstract goals serving as guiding life principles, become relatively important predictors of adolescents' self-reported violent behavior in school environments in which violence is relatively common. The study employed a students-nested-in-schools design. Arab and Jewish adolescents (N = 907, M age = 16.8), attending 33 Israeli schools, reported their values and their own violent behavior. Power values correlated positively, and universalism and conformity correlated negatively with self-reported violent behavior, accounting for 12% of the variance in violent behavior, whereas school membership accounted for 6% of the variance. In schools in which violence was more common, power values' relationship with adolescents' self-reported violence was especially positive, and the relationship of universalism with self-reported violence was especially negative.

Parental discipline and affection and children's prosocial behavior: genetic and environmental links.

The authors investigated genetic and environmental contributions to the relationships between children's (N=9,319 twin pairs) prosocial behavior and parental positivity and negativity toward them. Children's prosocial behavior was rated by parents at ages 3, 4, and 7 and by teachers at age 7. At each age, parents described their feelings and discipline toward each twin. Parental positivity was indexed by positive feelings and positive, non-coercive discipline, and parental negativity was indexed by negative feelings and coercive, punitive discipline. Genetics and the environment both contributed to individual differences in prosocial behavior and in parenting. At all ages, parental positivity correlated positively, and parental negativity correlated negatively with prosocial behavior. Genetic factors largely mediated the negative correlation between prosocial behavior and parental negativity. Shared environmental effects contributed mainly to the positive relationship between prosocial behavior and parental positivity. This pattern was found both cross-sectionally and longitudinally. The findings point to the importance of children's characteristics and of the parent-child relationship in family processes.

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.

The Longitudinal Israeli Study of Twins (LIST): children's social development as influenced by genetics, abilities, and socialization.

The goals, prospects and methods of the Longitudinal Israeli Study of Twins (LIST) are described. This study is interested in children's prosocial development from phenotypic, genetic and environmental perspectives. It focuses on measuring prosociality with a multi-trait multi-method approach, and relating it to children's general cognitive and sociocognitive abilities, and to parenting in the family. Other variables of interest such as children's temperament and parental values are discussed, as are ideas for further research.

Masculine girls and feminine boys: genetic and environmental contributions to atypical gender development in early childhood.

In this genetic study of atypical gender role development, parents of 5,799 twin pairs, ages 3 and 4, rated their twin children's masculinity and femininity. Boys were selected as gender atypical if they were highly feminine (top 5%, 10%, or 15%) relative to other boys, and girls were selected if they were highly masculine relative to other girls. Gender-atypical boys and girls were each divided into 2 groups: fully gender atypical (e.g., feminine boys also low on masculinity) and partially gender atypical (e.g., feminine boys who are not low on masculinity). DeFries-Fulker (DF; J. C. DeFries & D. W. Fulker, 1985, 1988) extremes analysis yielded moderate group heritability and substantial shared environment effects for atypical gender role behavior. However, for fully gender-atypical girls, group heritability accounted for most of the variance, and shared environment had no effect. The results are discussed in light of past studies and potential implications for atypical gender development.

Attachment to inanimate objects and early childcare: A twin study.

Extensive non-maternal childcare plays an important role in children's development. This study examined a potential coping mechanism for dealing with daily separation from caregivers involved in childcare experience - children's development of attachments toward inanimate objects. We employed the twin design to estimate relative environmental and genetic contributions to the presence of object attachment, and assess whether childcare explains some of the environmental variation in this developmental phenomenon. Mothers reported about 1122 3-year-old twin pairs. Variation in object attachment was accounted for by heritability (48%) and shared environment (48%), with childcare quantity accounting for 2.2% of the shared environment effect. Children who spent half-days in childcare were significantly less likely to attach to objects relative to children who attended full-day childcare.

Shyness discriminates between children with 22q11.2 deletion syndrome and Williams syndrome and predicts emergence of psychosis in 22q11.2 deletion syndrome.

BACKGROUND: 22q11.2 deletion syndrome (22q11.2DS) is a common neurogenetic syndrome associated with high rates of psychosis. The aims of the present study were to identify the unique temperament traits that characterize children with 22q11.2DS compared to children with Williams syndrome (WS) and typically developing (TD) controls, and to examine temperamental predictors of the emergence of psychosis in 22q11.2DS. METHODS: The temperament of 55 children with 22q11.2DS, 36 with WS, and 280 TD children was assessed using the Emotionality, Activity, Sociability (EAS) Temperament Survey, Parental Ratings. The presence of a psychotic disorder was evaluated in 49 children and adolescents with 22q11.2DS at baseline and again 5.43 ± 2.23 years after baseline temperament assessment. RESULTS: Children with 22q11.2DS scored higher on Shyness compared to WS and TD controls. Children with 22q11.2DS and WS scored higher on Emotionality and lower on Activity compared to TD controls. Shyness was more severe in older compared to younger children with 22q11.2DS. Baseline Shyness scores significantly predicted the later emergence of a psychotic disorder at follow-up, in children with 22q11.2DS. CONCLUSIONS: Our results suggest that shyness is an early marker associated with the later emergence of psychosis in 22q11.2DS.

The dopamine D4 receptor gene shows a gender-sensitive association with cognitive empathy: evidence from two independent samples.

Increasing evidence points to a role of dopaminergic pathways in modulating social behavior. Specifically, a polymorphic region in the third exon of the Dopamine D4 receptor (DRD4) has been associated with a host of social behaviors, often in an environment-sensitive manner. Empathy is thought to be an important motivator of prosocial behaviors and can be seen as multifaceted, combining cognitive empathy (CE) and emotional empathy (EE). In the current study, we analyzed the association between DRD4 and the 2 aspects of empathy, as well as the effect of gender on this association. In Study 1, a large sample of adult participants (N = 477) was inventoried for general empathy, CE, and EE and genotyped for the DRD4 exon 3 polymorphism. Women scored higher than men on all empathy measures and no main effect of genotype was observed. It is important that a significant interaction between genotype and gender emerged specifically for CE, with women carriers of the 7R-allele scoring higher than noncarriers, whereas in men 7R-carriers scored lower than -7R. Notably, these findings were replicated in an independently recruited sample (N = 121) in Study 2. The current report shows that the DRD4 exon3 polymorphism is associated with CE and the direction of the association is gender-sensitive.