Using inclusive sampling to highlight specific executive functioning impairments in autism spectrum disorder¹

¹The research represented in this article was conducted by the second author for the degree of Master of Science, Edinburgh University.

Abstract

Objectives: The aim of the study is to help identify the nature of impaired executive functioning (EF) in children with autism spectrum disorder (ASD). It is also argued that participant sampling by age alone should inform experimental research on EF, as selection through IQ matching may weaken any experimental effects.

Methods: Sixteen children with ASD across a wide range of Nonverbal IQ (NVIQ) and 16 neurotypical control children matched on age alone were given two different types of computerized sequencing game. Both required top-down organization, but in one case the sequence had to be self-generated while in the second it had to be learned and strictly followed. Measures of learning success in relation to NVIQ, and information processing demands were made.

Results: Children with ASD were significantly impaired on the first task only, especially when the processing demands were increased. The effects were particularly pronounced for children with below average NVIQ.

Conclusions: The study indicates a selective problem with self-organized sequencing in ASD with implications for certain real world contexts, but also points to a need for more inclusive sampling of children in order to fully expose specific executive impairments in autism spectrum disorder.

Keywords:

• autism spectrum disorder
• executive functioning, sequencing
• nonverbal IQ
• working memory

Acknowledgements

We should like to sincerely thank the pupils and staff at Kaimes Special School and Gracemount High School, Edinburgh and also Dunblane High School, Dunblane for their patience and co-operation. We should also like to acknowledge Karl Monsen for his prototyping and programming of the games used in this study.

Notes

¹ The research represented in this article was conducted by the second author for the degree of Master of Science, Edinburgh University.

¹ Children with moderate to severe learning difficulties attended a different school in Central Edinburgh for children with ASD and Pervasive Developmental Disorder (PDD).

² Positive transfer from the two tasks is no more likely than negative transfer as the tasks were similar in terms of stimulus properties but different in terms of how they should be sequenced across the three levels.

³ This could manifest itself both in terms of being able to carry out a thorough visual search as well as well as in constructing a mental plan — although these are themselves almost certainly inter-related.