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.

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.

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.

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.

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.

Autonomic correlates of children's concern and disregard for others.

Psychophysiological research on empathy and prosociality in children has focused most often on cardiac activity, heart rate (HR), and HR deceleration in particular. We examined these processes in 7-year-old children during two empathy mood inductions. We independently assessed children's responses to others' distress in two different contexts: structured probes (simulated pain) and maternal interviews. We identified three groups of children who showed either (1) concern for others in distress (i.e., empathy and prosocial behaviors), (2) active disregard (i.e., anger/hostility and antisocial behavior), or (3) passive disregard (i.e., little or no concern). We compared groups on HR and HR deceleration. The active disregard group consistently showed the lowest HR both when groups were based on structured probes and on mothers' reports. Children who showed passive disregard displayed little self-distress during other's distress and different patterns of association of self-distress and HR than the other two groups. Active and passive disregard thus may reflect two different aspects of lack of concern for others. HR deceleration was seen for all three groups, suggesting it is not necessarily a cardiac index of concern for others. Interdisciplinary approaches and multiple-systems analysis are needed to better understand psychobiological substrates.

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.

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.

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.

The role of language in concern and disregard for others in the first years of life.

We examined the associations between language skills and concern and disregard for others in young children assessed longitudinally at ages 14, 20, 24, and 36 months, testing the hypothesis that language skills have a specific role (distinct from that of general cognitive ability) in the development of concern and disregard for others. We found that higher language skills predicted higher concern for others and lower disregard for others even after controlling for general cognitive ability, whereas the association between general cognitive ability and concern/disregard for others was not significant after controlling for language skills. Language skills at 14 months predicted concern for others at 36 months, and results suggested that the relations between language skills and concern and disregard for others begin early in development. Gender differences in concern and disregard for others were at least partially explained by differences in language skills. These results support the specific role of language skills in concern and disregard for others.

Epigenetic and genetic factors predict women's salivary cortisol following a threat to the social self.

Evidence suggests that the reactivity of the Hypothalamus-Pituitary-Adrenal axis (HPAA) is modulated by both genetic and environmental variables. Of special interest are the underlying molecular mechanisms driving gender differences to psychosocial stressors. Epigenetic mechanisms that sculpt the genome are ideal candidates for mediating the effects of signals on the HPAA. In the current study, we analyzed by pyrosequencing, bisulfite-treated buccal DNA from male and female university students who participated in the Trier Social Stress Test (TSST). A linear regression model was used to ascertain the effects of sex, CpG methylation and genes on stress response. Total cortisol output (area under the curve, AUC) was significantly predicted by glucocorticoid receptor (NR3C1) exon 1F methylation (averaged across 39 CpG sites) solely in female subjects. A single CpG site located in the exon 1F noncanonical nerve growth factor-inducible protein A (NGFI-A) transcription factor was a highly significant predictor of AUC in female subjects. Additionally, variations in the estrogen receptor alpha (ESR1) and the serotonin transporter promoter (5-HTTLPR) genes were independent additive predictors of AUC. The full model accounted for half of the variance (50.06%) in total cortisol output. Notably, this is the first demonstration that epigenetic changes at the GR exon 1F correlate with HPAA reactivity. These findings have important implications for understanding the molecular mechanisms underlying gender differences in stress-related disorders and underscore the unique value of modeling both epigenetic and genetic information in conferring vulnerability to stress.

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.

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.

Vasopressin selectively impairs emotion recognition in men.

The biological mechanisms underlying empathy, the ability to recognize emotions and to respond to them appropriately, are only recently becoming better understood. This report focuses on the nonapeptide arginine-vasopressin (AVP), which plays an important role in modulating social behavior in animals, especially promoting aggressive behavior. Towards clarifying the role of AVP in human social perception we used the Reading of the Mind in the Eyes Test and intranasal administration of AVP to show that AVP leads to a significant decrease in emotion recognition. Moreover, when comparing photos of males vs. females, all viewed by males, AVP had an effect on gender-matched photos only. Furthermore, the effect of AVP was restricted to recognition of negative emotions while leaving recognition of positive emotions unaffected. The current report emphasizes the selective role of AVP in male emotional perception and empathy, a core element in all human social interactions.

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.

AVPR1A variant associated with preschoolers' lower altruistic behavior.

The genetic origins of altruism, defined here as a costly act aimed to benefit non-kin individuals, have not been examined in young children. However, previous findings concerning adults pointed at the arginine vasopressin receptor 1A (AVPR1A) gene as a possible candidate. AVPR1A has been associated with a range of behaviors including aggressive, affiliative and altruistic phenotypes, and recently a specific allele (327 bp) of one of its promoter region polymorphisms (RS3) has been singled out in particular. We modeled altruistic behavior in preschoolers using a laboratory-based economic paradigm, a modified dictator game (DG), and tested for association between DG allocations and the RS3 "target allele." Using both population and family-based analyses we show a significant link between lower allocations and the RS3 "target allele," associating it, for the first time, with a lower proclivity toward altruistic behavior in children. This finding helps further the understanding of the intricate mechanisms underlying early altruistic behavior.

Differential genetic susceptibility to child risk at birth in predicting observed maternal behavior.

This study examined parenting as a function of child medical risks at birth and parental genotype (dopamine D4 receptor; DRD4). Our hypothesis was that the relation between child risks and later maternal sensitivity would depend on the presence/absence of a genetic variant in the mothers, thus revealing a gene by environment interaction (GXE). Risk at birth was defined by combining risk indices of children's gestational age at birth, birth weight, and admission to the neonatal intensive care unit. The DRD4-III 7-repeat allele was chosen as a relevant genotype as it was recently shown to moderate the effect of environmental stress on parental sensitivity. Mothers of 104 twin pairs provided DNA samples and were observed with their children in a laboratory play session when the children were 3.5 years old. Results indicate that higher levels of risk at birth were associated with less sensitive parenting only among mothers carrying the 7-repeat allele, but not among mothers carrying shorter alleles. Moreover, mothers who are carriers of the 7-repeat allele and whose children scored low on the risk index were observed to have the highest levels of sensitivity. These findings provide evidence for the interactive effects of genes and environment (in this study, children born at higher risk) on parenting, and are consistent with a genetic differential susceptibility model of parenting by demonstrating that some parents are inherently more susceptible to environmental influences, both good and bad, than are others.

Children's low affective perspective-taking ability is associated with low self-initiated pro-sociality.

Children's affective perspective-taking (APT) may provide a basis for efficient social interaction. The APT abilities of 83 children from 46 same-sex sibling pairs (ages 36 to 72 months, M = 52.8; SD = 12.6) were assessed through their reactions to affectively loaded story situations, and children whose APT ability (but not general cognitive abilities) was low relative to other children of their age were designated as Low-APT children. These children were not less pro-social when specific social cues or requests for pro-social behavior were given by experimenters. However, low APT may hinder children's ability to infer the need for pro-social action from relatively subtle social cues. Although 46.9% of nonlow APT children behaved pro-socially in at least two of three opportunities they were given to perform a self-initiated pro-social behavior, none of the children who were low on APT did.