Exploring the structure and the roles of executive functions in typically developing children and children with autism spectrum disorder

Abstract

Executive functions are a range of goal-directed cognitive abilities. Miyake et al. (2000) suggest that there are 3 correlated but separable executive functions; working memory, inhibition, and shifting. Whilst Fisk and Sharp (2004) add the ability to retrieve information from long-term memory as a fourth. While the developmental trajectories and structures of working memory, inhibition and shifting have been examined widely, there has been less research investigating retrieval from long-term memory. There has also been little research exploring contributions of executive functions to academic achievement in typically developing children, and whilst there is evidence that deficits in executive function are associated with ASD, there is very little research investigating the relationship between EFs and autistic characteristics. The first study presented in this thesis recruited 187 typically developing children aged 7, 10 and 14 years to investigate the structure of working memory, inhibition, shifting and retrieval from long-term memory (via verbal fluency). The results suggested a four-factor structure was the best fit to the data across all age groups. The second study examined the extent to which the executive functions predicted recent National Curriculum Levels in English and Mathematics. Although the majority of the executive functions were correlated to attainment, there were clear developmental differences in terms of the extent to which executive functions predicted attainment. 30 children with autism and their parents participated in the third study. The results revealed no correlation between laboratory measures of executive functions and parent-ratings of executive functions, and found few significant correlations between executive functions and autism characteristics. Analyses suggested that children with autism can be clustered into 3 groups, according to severity of autism characteristics and executive function difficulties. Further implications for research and practice in executive function in both children with and without autism are explored.