Date of Award


Degree Type


Degree Name

Doctor of Philosophy in Psychology



First Advisor

W. Grant Willis


The purposes of the present study were (a) to investigate the performance of three groups of children, those diagnosed with Attention-deficit Hyperactivity Disorder, those diagnosed with Developmental Language Disorder, and a matched group of nondisabled children on a battery of neuropsychological tasks purported to measure executive function, and (b) to investigate the validity of tasks used to measure executive function across three age levels. A double-dissociation paradigm was used. Six executive function tasks and two nonexecutive function (i.e., vocabulary) tasks were administered to all participants in a counterbalanced order. Results revealed significant group and age effects. Significant differences were found between groups on three executive function measures, with the nondisabled group differing from the two clinical groups on two of the executive function measures, and the clinical groups differing on one executive function measure. Additionally, results revealed significant differences between the Language Disorder group and the other two groups on the two nonexecutive function measures. The relationships between age and all measures were linear. Collectively, the results did not provide evidence of a clear double dissociation suggesting that deficits in executive functions may not be specific to ADHD. Theoretical and clinical implications were discussed in terms of executive functioning in child clinical populations, and suggestions for future research were advanced.



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