Ariel Knafo-Noam

Oxytocin receptor and vasopressin receptor 1a genes are respectively associated with emotional and cognitive empathy.

Empathy is the ability to recognize and share in the emotions of others. It can be considered a multifaceted concept with cognitive and emotional aspects. Little is known regarding the underlying neurochemistry of empathy and in the current study we used a neurogenetic approach to explore possible brain neurotransmitter pathways contributing to cognitive and emotional empathy. Both the oxytocin receptor (OXTR) and the arginine vasopressin receptor 1a (AVPR1a) genes contribute to social cognition in both animals and humans and hence are prominent candidates for contributing to empathy. The following research examined the associations between polymorphisms in these two genes and individual differences in emotional and cognitive empathy in a sample of 367 young adults. Intriguingly, we found that emotional empathy was associated solely with OXTR, whereas cognitive empathy was associated solely with AVPR1a. Moreover, no interaction was observed between the two genes and measures of empathy. The current findings contribute to our understanding of the distinct neurogenetic pathways involved in cognitive and emotional empathy and underscore the pervasive role of both oxytocin and vasopressin in modulating human emotions.

Synchronous rhythmic interaction enhances children's perceived similarity and closeness towards each other.

Inter-personal synchronization is important for performing many cooperative tasks. Notably, synchrony has also been shown to have considerable positive social influences, possibly mediated by synchrony-induced changes in social attitude such as an increased sense of similarity and affiliation between interacting individuals. This effect has been demonstrated in adults, but it is unknown whether synchrony might have a similar impact on the social attitudes of children. We thus set to directly examine the influence of synchronous rhythmic interaction on perceived similarity and closeness in pairs of 8–9 year old children. We found that children who had participated in a synchronous interaction regarded their interacting partner as more similar and closer to themselves than children who had not interacted at all or who had taken part in an asynchronous interaction. These findings reveal that synchronous interaction can positively alter social attitudes between interacting children, suggesting a potential mechanism by which synchrony may enhance positive social interaction through attitudinal shift.

The prosocial personality and its facets: genetic and environmental architecture of mother-reported behavior of 7-year-old twins

Children vary markedly in their tendency to behave prosocially, and recent research has implicated both genetic and environmental factors in this variability. Yet, little is known about the extent to which different aspects of prosociality constitute a single dimension (the prosocial personality), and to the extent they are intercorrelated, whether these aspects share their genetic and environmental origins. As part of the Longitudinal Israeli Study of Twins (LIST), mothers of 183 monozygotic (MZ) and dizygotic (DZ) 7-year-old twin pairs (51.6% male) reported regarding their children’s prosociality using questionnaires. Five prosociality facets (sharing, social concern, kindness, helping, and empathic concern) were identified. All five facets intercorrelated positively (r > 0.39) suggesting a single-factor structure to the data, consistent with the theoretical idea of a single prosociality trait. Higher MZ than DZ twin correlations indicated genetic contributions to each prosociality facet. A common-factor-common-pathway multivariate model estimated high (69%) heritability for the common prosociality factor, with the non-shared environment and error accounting for the remaining variance. For each facet, unique genetic and environmental contributions were identified as well. The results point to the presence of a broad prosociality phenotype, largely affected by genetics; whereas additional genetic and environmental factors contribute to different aspects of prosociality, such as helping and sharing.

Temperament and peer problems from early to middle childhood: Gene-environment correlations with negative emotionality and sociability.

Based in a transactional framework in which childrens own characteristics and the social environment influence each other to produce individual differences in social adjustment, we investigated relationships between childrens peer problems and their temperamental characteristics, using a longitudinal and genetically informed study of 939 pairs of Israeli twins followed from early to middle childhood (ages 3, 5, and 6.5). Peer problems were moderately stable within children over time, such that children who appeared to have more peer problems at age 3 tended to have also more peer problems at age 6.5. Childrens temperament accounted for 10%-22% of the variance in their peer problems measured at the same age and for 2%-7% of the variance longitudinally. It is important that genetic factors accounted for the association between temperament and peer problems and were in line with a gene-environment correlation process, providing support for the proposal that biologically predisposed characteristics, particularly negative emotionality and sociability, have an influence on childrens early experiences of peer problems. The results highlight the need for early and continuous interventions that are specifically tailored to address the interpersonal difficulties of children with particular temperamental profiles.

The Motivational Foundations of Prosocial Behavior From A Developmental Perspective–Evolutionary Roots and Key Psychological Mechanisms: Introduction to the Special Section

Prosocial behavior is versatile, multifaceted, and complex. This special section seeks to advance coherent, integrative understanding of prosocial development by addressing this topic through the prism of motivations. This conceptual Introduction presents key ideas that provide a framework for thinking about motivation for prosocial behavior and its development. It outlines the evolutionary roots of prosocial behavior, underscoring the interdependent roles of nature and nurture. This is followed by a discussion of several key psychological mechanisms reflecting different motivations for prosocial action (empathy for a distressed other, concern about anothers goal, desire to act in accordance with internalized prosocial norms, and guilt). We discuss the critical components of each motivation and highlight pertinent contributions of the special section articles.

The role of personal values in children’s costly sharing and non-costly giving

This study examined whether childrens values, global and abstract motivations serving as guiding principles, are organized similarly to those of adults, whether values can predict individual differences in childrens sharing behaviors, and whether the normative nature of the situation influences the expression of these individual differences. Children (N=243, ages 5-12years) participated in a values ranking task as part of a visit to a science museum. The majority of children (n=150) also participated in a task examining costly sharing (i.e., sharing that results in giving up part of ones own resources) and non-costly giving (i.e., giving that does not influence ones own share). Starting from 5years of age, children showed a structure of values similar to that of adolescents and adults, specifically contrasting preferences for opposing values (i.e., self-transcendence with self-enhancement and openness to change with conservation). Importance given to self-transcendence values related positively to costly sharing but not to non-costly giving, indicating that in situations where it is more normative to share, individual differences in values are less expressed in childrens actual sharing. In addition, childrens sex and age moderated the relation between values and behavior. Childrens values are an important aspect of their developing personalities. Taking them into consideration can greatly promote the research of prosocial and normative development as well as our understanding of individual differences in childrens behavior.

Identity exploration and commitment in early adolescence: Genetic and environmental contributions.

Identity formation is a key developmental task in adolescence. Although many adolescents in modern societies face issues of identity, there are substantial individual differences in identity exploration and commitment. Little is known about the origins of these individual differences. The current study investigated the genetic and environmental contributions to identity formation. In total, 571 11-year-old twins (85 monozygotic complete pairs and 176 dizygotic complete pairs) reported on their identity formation, using the Dimensions of Identity Development Scale (DIDS; Luyckx, Schwartz, Berzonsky, et al., 2008), as part of the Longitudinal Israeli Study of Twins (LIST; Avinun & Knafo, 2013). Multidimensional scaling analysis and confirmatory factor analysis supported the presence of all 5 dimensions at this young age: commitment making, exploration in-breadth, ruminative exploration, identification with commitment, and exploration in-depth. However, a model where exploration in-depth was divided into two subscales had a better fit to the data. Monozygotic twins were more similar to each other than dizygotic twins on all dimensions, except for one of the exploration in-depth subscales, supporting the idea that individual differences in various dimensions of identity formation are at least partially influenced by genetics (18–45%). For these dimensions, the rest of the variance was explained by nonshared environment effects (55–82%). Only one of the exploration in-depth subscales, that is, the tendency to explore commitments through discussion with others, showed evidence for the influence of the environment shared by twins (21%) but no genetic effect. Implications of the findings regarding the role of genetics and environment to identity formation are discussed.

Parental brain-derived neurotrophic factor genotype, child prosociality, and their interaction as predictors of parents’ warmth

Parental warmth has been associated with various child behaviors, from effortful control to callous‐unemotional traits. Factors that have been shown to affect parental warmth include heritability and child behavior. However, there is limited knowledge about which specific genes are involved, how they interact with child behavior, how they affect differential parenting, and how they affect fathers. We examined what affects paternal and maternal warmth by focusing on the childs prosocial behavior and parents’ genotype, specifically a Valine to Methionine substitution at codon 66 in the brain‐derived neurotrophic factor (BDNF) gene.

Twin's Birth-Order Differences in Height and Body Mass Index From Birth to Old Age: A Pooled Study of 26 Twin Cohorts Participating in the CODATwins Project

We analyzed birth order differences in means and variances of height and body mass index (BMI) in monozygotic (MZ) and dizygotic (DZ) twins from infancy to old age. The data were derived from the international CODATwins database. The total number of height and BMI measures from 0.5 to 79.5 years of age was 397,466. As expected, first-born twins had greater birth weight than second-born twins. With respect to height, first-born twins were slightly taller than second-born twins in childhood. After adjusting the results for birth weight, the birth order differences decreased and were no longer statistically significant. First-born twins had greater BMI than the second-born twins over childhood and adolescence. After adjusting the results for birth weight, birth order was still associated with BMI until 12 years of age. No interaction effect between birth order and zygosity was found. Only limited evidence was found that birth order influenced variances of height or BMI. The results were similar among boys and girls and also in MZ and DZ twins. Overall, the differences in height and BMI between first- and second-born twins were modest even in early childhood, while adjustment for birth weight reduced the birth order differences but did not remove them for BMI.

Twin's Birth-Order Differences in Height and Body Mass Index From Birth to Old Age: A Pooled Study of 26 Twin Cohorts Participating in the CODATwins Project.

We analyzed birth order differences in means and variances of height and body mass index (BMI) in monozygotic (MZ) and dizygotic (DZ) twins from infancy to old age. The data were derived from the international CODATwins database. The total number of height and BMI measures from 0.5 to 79.5 years of age was 397,466. As expected, first-born twins had greater birth weight than second-born twins. With respect to height, first-born twins were slightly taller than second-born twins in childhood. After adjusting the results for birth weight, the birth order differences decreased and were no longer statistically significant. First-born twins had greater BMI than the second-born twins over childhood and adolescence. After adjusting the results for birth weight, birth order was still associated with BMI until 12 years of age. No interaction effect between birth order and zygosity was found. Only limited evidence was found that birth order influenced variances of height or BMI. The results were similar among boys and girls and also in MZ and DZ twins. Overall, the differences in height and BMI between first- and second-born twins were modest even in early childhood, while adjustment for birth weight reduced the birth order differences but did not remove them for BMI.