Environmental susceptibility for all: A data-driven approach suggests individual differences in domain-general and domain-specific patterns of environmental susceptibility.

How we are influenced by our environment is a fundamental question in developmental science. Theories and empirical research have claimed that some individuals are susceptible to environmental influences and others are much less susceptible. The present study addressed four questions: (1) Is environmental susceptibility a continuous or categorical construct? (2) Is environmental susceptibility unidimensional (i.e., domain general) or multidimensional (i.e., domain specific)? (3) Are there genetic contributions to individual differences in environmental susceptibility? (4) What are the temperamental characteristics of different environmental susceptibility patterns? We used child- and mother-report data from a sample of 11-year-old twins (N = 1,507) and applied a novel data-driven approach to assess an environmental susceptibility space, based on simultaneous associations between multiple environmental exposures (18 measures relating to parenting, parent, peer, and twin relationships) and developmental outcomes (10 measures relating to empathy, prosocial behavior, aggression, and self-esteem). The results suggest that the environmental susceptibility space we assessed is better conceptualized as continuous and multidimensional. Different children showed susceptibility to different contexts and variation in domain-general versus domain-specific patterns. A comparison of distances between monozygotic and dizygotic twins within the space demonstrated genetic contributions. Finally, susceptibility patterns could not be differentiated based on a specific temperament trait, but rather related to temperament profiles.

The empathic personality profile: Using personality characteristics to reveal genetic, environmental, and developmental patterns of adolescents' empathy.

OBJECTIVE: How do genetic and environmental processes affect empathy during early adolescence? This study illuminated this question by examining the aetiology of empathy with the aetiology of other personality characteristics. METHOD: Israeli twin adolescents rated their empathy and personality at ages 11 (N = 1176) and 13 (N = 821) (733 families, 51.4% females). Parents rated adolescents' emotional empathy. Adolescents performed an emotion recognition task, indicating cognitive empathy. RESULTS: Using a cross-validated statistical learning algorithm, this study found emotional and cognitive "empathic personality profiles," which describe and predict self-reported empathy from nuanced Big-Five personality characteristics, or "nuances" (i.e., individual items). These profiles predicted empathy moderately (R2  = 0.17-0.24) and were stable and robust, within each age and between ages. They also predicted empathy in a new sample of older nontwin adolescents (N = 96) and were validated against non-self-report empathy measures. Both emotional and cognitive empathy were predicted by nuances representing positive attitudes toward others, trust, forgiveness, and openness to experiences. Emotional empathy was also predicted by nuances representing anxiousness and negative reactivity. Twin analyses revealed overlapping genetic and environmental influences on empathy and the empathic personality profiles and overlapping environmental influences on empathy-personality change. CONCLUSIONS: This study demonstrates how addressing the complexity of individuals' personalities can inform adolescents' empathy development.

The special role of middle childhood in self-control development: Longitudinal and genetic evidence.

Despite the importance of self-control for well-being and adjustment, its development from early childhood to early adolescence has been relatively understudied. We addressed the development of mother-reported self-control in what is likely the largest and longest longitudinal twin study of the topic to this day (N = 1889 individual children with data from at least one of five waves: ages 3, 5, 6.5, 8-9 and 11 years). We examined rank-order change in self-control from early childhood to early adolescence, genetic and environmental contributions to variance in the trait and differential developmental trajectories. The relative contribution of genetic and environmental factors to change and stability was also examined. Results point at middle childhood as a period of potential transition and change. During this period the rank-order stability of self-control increases, heritability rates substantially rise, and a cross-over occurs in two of the self-control trajectories. Nonadditive genetic effects contribute to both stability and change in self-control while the nonshared environment contributes mostly to change, with no effect for the shared environment. Our findings suggest that new genetic factors, that emerge around age 6.5 and whose effect on self-control is carried on along development, may partially account for changes in self-control around late middle childhood, and explain the growing stability in the trait approaching early adolescence. We discuss the implications of the special role of middle childhood for self-control development.

Are there positive effects of having a sibling with special needs? Empathy and prosociality of twins of children with non-typical development.

This study examined whether typically developing (TD) twins of non-TD children demonstrate enhanced empathy and prosociality. Of 778 Hebrew-speaking Israeli families who participated in a twin study, 63 were identified to have a non-TD child with a TD twin, and 404 as having both twins TD. TD twins of non-TD children (27% males) were compared to the rest of the cohort of TD children (46% males) on measures of empathy and prosociality. Participants were 11 years old. TD twins of non-TD children scored significantly higher than TD twins of TD children in a measure of cognitive empathy (d = .43). No differences were found in emotional empathy and prosociality. The specificity of the positive effect on cognitive empathy is discussed.

Are Different Individuals Sensitive to Different Environments? Individual Differences in Sensitivity to the Effects of the Parent, Peer and School Environment on Externalizing Behavior and its Genetic and Environmental Etiology.

Externalizing behavior is substantially affected by genetic effects, which are moderated by environmental exposures. However, little is known about whether these moderation effects differ depending on individual characteristics, and whether moderation of environmental effects generalizes across different environmental domains. With a large sample (N = 1,441 individuals) of early adolescent twins (ages 11 and 13), using a longitudinal multi-informant design, we tested interaction effects between negative emotionality and both positive and negative aspects of three key social domains: parents, peers, and schools, on the phenotypic variance as well as the etiology of externalizing. Negative emotionality moderated some of the environmental effects on the phenotypic, genetic, and environmental variance in externalizing, with adolescents at both ends of the negative emotionality distribution showing different patterns of sensitivity to the tested environmental influences. This is the first use of gene-environment interaction twin models to test individual differences in environmental sensitivity, offering a new approach to study such effects.

Sensitivity, but to which environment? Individual differences in sensitivity to parents and peers show domain-specific patterns and a negative genetic correlation.

The idea that individuals differ in their sensitivity to the environment's effects is a cornerstone of developmental science. It has been demonstrated repeatedly, for different kinds of stressors, outcomes, and sensitivity markers. However, almost no empirical work was done to examine whether environmental sensitivity is domain-general (i.e., the same individuals are sensitive to different environmental contexts) or domain-specific (i.e., different individuals are sensitive to different environmental contexts), despite its importance to understanding human development, learning, and behavior. To address this question, phenotypic sensitivity to parents and to peers were compared in 1313 11-year-old Israeli adolescent twins. We found that, (1) our phenotypic markers indeed moderate environmental influences, with a discriminant predictive utility, (2) adolescents who are sensitive to their parents are not necessarily sensitive to their peers, and (3) sensitivity to parents and sensitivity to peers have different etiologies and show a negative genetic correlation, indicating that adolescents carrying genetic markers for sensitivity to parents are less likely to carry genetic markers for sensitivity to peers. These findings suggest that environmental sensitivity shows domain-specific patterns, as different individuals can be sensitive to different environments. We discuss the theoretical, empirical, and practical implications of domain-specificity of environmental sensitivity.

Will you touch a dirty diaper? Attitudes towards disgust and behaviour.

Individuals differ in their willingness to engage with disgusting stimuli (e.g., dirty diapers). We propose that such differences are associated with attitudes towards disgust. Specifically, we predicted that people with less negative attitudes towards disgust (i.e., those who evaluate disgust less negatively) would be more willing to engage with disgusting stimuli. We asked participants to engage with disgusting stimuli in the laboratory and used two measures that assess behavioural and affective or cognitive components of attitudes towards disgust. As predicted, less negative attitudes towards disgust were associated with greater engagement with disgusting stimuli, above and beyond the current experience of disgust and the tendency to experience disgust. These findings stress the importance of attitudes towards emotions in understanding emotion-relevant behaviour.

What you like is what you try to get: Attitudes toward emotions and situation selection.

Why do people expose themselves to certain emotional stimuli and avoid others? We propose that what people want to feel is linked to attitudes toward emotions. In 3 studies, we show that individuals with more (vs. less) negative attitudes toward an emotion were more (vs. less) likely to avoid stimuli that induce that emotion. People who evaluated disgust (or joy) less favorably than others were less likely to expose themselves to disgusting (or joyful) pictures (Study 1). These links were emotion-specific and could not be explained by differences in state or trait emotion (Study 2) or in emotional reactivity (Study 3). We were further able to show that the choice of emotion-inducing stimuli affected emotional experience in a congruent manner. People with more (vs. less) negative attitudes toward disgust (or sadness) were more likely to avoid disgusting (or sad) stimuli, resulting in more intense experiences of disgust (or sadness; Study 2). Finally, people with more negative attitudes toward disgust chose to avoid more disgusting stimuli, whether attitudes were assessed explicitly or implicitly (Study 3). These findings suggest that people avoid stimuli that induce emotions that they evaluate less favorably, even when such evaluations are not consciously accessible. (PsycINFO Database Record

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. (PsycINFO Database Record