Individual differences in theory of mind ability in middle childhood and links with verbal ability and autistic traits: a twin study.
ABSTRACT Identifying the causal processes involved in theory of mind (ToM) development during childhood is an important goal for social neuroscience. This study aimed to investigate, for the first time, the extent to which individual differences in ToM are influenced by genes and environment in middle childhood, and to assess how ToM is linked to autistic-like behaviors and verbal ability. Over 600 9-year-old twin pairs from a subsample of the Twins Early Development Study were assessed on an advanced test of ToM and on verbal ability. Parents, teachers, and the children themselves provided ratings of the twins' autistic traits (social impairments, communication impairments, and restricted repetitive behaviors and interests), using an abbreviated version of the Childhood Asperger Syndrome Test. Autistic traits, particularly communication impairments, significantly predicted ToM performance. Verbal ability showed the strongest phenotypic association with ToM. Twin model-fitting was employed to investigate the causes of this association. Much of the variation in ToM ability and in verbal ability was explained by environmental influences, with modest heritabilities for each, but their association was almost fully explained by shared genetic effects. The possible neural basis underlying this association is discussed.
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ABSTRACT: 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.Journal of Abnormal Child Psychology 08/2013; 42(4). · 3.09 Impact Factor
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ABSTRACT: Evidence that conversations about the mind foster improvements in theory of mind (ToM) is growing, but their efficacy in typically developing school-aged children has yet to be demonstrated. To address this gap, we designed a conversation-based training program for 9- and 10-year-olds and measured its effectiveness by pre- and post-test comparisons of performance on age-appropriate ToM tasks for two groups (matched at pre-test for gender, age, socioeconomic background, verbal ability, reading comprehension, executive functions, and ToM) who were assigned to either the intervention condition (n=45) or an active control condition (n=46). The intervention group showed significantly greater gains in ToM than the control group; this contrast was stable over 2months, and (in a subsample) the improvement in ToM was independent of any changes in executive functions. Implications for the role of conversations about the mind in children's mental state reasoning are discussed.Journal of Experimental Child Psychology 05/2014; 126C:52-67. · 3.12 Impact Factor
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ABSTRACT: A large body of work has focused on children's ability to attribute mental states to other people, and whether these abilities are influenced by the extent and nature of children's social interactions. However, it remains largely unknown which developmental factors shape children's ability to influence the mental states of others. Building on the suggestion that collaborative experiences early in life might be crucial for the emergence of mental coordination abilities, here we assess the relative contribution of social exposure to familial and non-familial agents on children's communicative adjustments to their mental model of an addressee ('audience design'). During an online interactive game, five-year-olds spontaneously organized their non-verbal communicative behaviors according to their beliefs about an interlocutor. The magnitude of these communicative adjustments was predicted by the time spent at daycare, from birth until four years of age, over and above effects of familial social environment. These results suggest that the degree of non-familial social interaction early in life modulates the influence that children's beliefs have on their referential communicative behavior.PLoS ONE 08/2013; 8(8):e72667. · 3.53 Impact Factor