Date of Award
Doctor of Philosophy
This study examined the development of social cognition in children with and without autism spectrum disorder (ASD), as well as the influence of behavioral and molecular genetics on these higher-order cognitive abilities. Specifically, it was hypothesized that children with ASD would perform more poorly on all social cognitive tasks compared with typically developing peers. In addition, it was hypothesized that typically developing children who performed better on a simpler social cognitive task at ages 3 or 4 would perform better at follow-up (i.e., one time between the ages of 6-10). Lastly, it was hypothesized that children who had at least one risk allele in both the DRD4 and the 5-HTTLPR polymorphisms would perform worse than those who had at least one risk allele in either polymorphism, who, in turn, would perform worse than children without any risk alleles. The twin sample included 62 families of multiples (twins, triplets, or quadruplets) who were recruited through the Southern Illinois Twins and Siblings Study (SITSS), and the ASD sample included 25 children who were recruited from the Center for Autism Spectrum Disorders at SIU. Significant group differences were found for children's performance on all of the social cognitive tasks. Furthermore, results showed that some areas of social cognition (theory of mind and the understanding of non-literal language) are more influenced by genetic factors than are other cognitive skills. Lastly, results from the molecular genetic analyses suggest that basic social cognitive skills (e.g., theory of mind) may be influenced by underlying biological factors in the serotonergic and dopaminergic pathways. The present study provided useful information on how psychological and genetic factors influence the development of social cognitive abilities in children with and without ASD.
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