The contribution of central and peripheral processes to slow reaction times in children with and without attention-deficit/hyperactivity disorder (ADHD)

open_access
Open Access
Author:
Moore, Amy Nichole
Graduate Program:
Psychology
Degree:
Master of Science
Document Type:
Master Thesis
Date of Defense:
July 16, 2012
Committee Members:
Cynthia L Huang Pollock, Thesis Advisor/Co-Advisor
Keywords:
ADHD
processing speed
serial reaction time
Abstract:
Children with attention-deficit/hyperactivity disorder (ADHD) have been found to respond more slowly than typically-developing controls across a number of simple cognitive tasks. However, the locus of these group differences is unclear because reaction times reflect the influence of peripheral processes (e.g., motor output) and central processes (e.g., basic cognitive efficiency), which have been independently implicated as being impaired in children with ADHD. This study sought to examine the degree to which these processes contribute to group differences in reaction times on a four-choice cognitive task by taking advantage of the differential effect of practice on central but not peripheral demands. That is, when external task demands are held constant, peripheral processing demands are believed to be relatively stable across a task and central processing demands are thought to decrease with practice as participants become increasingly efficient at completing a task. Results revealed that children with ADHD responded more slowly than controls throughout the task, and that children with ADHD did not show greater improvement relative to controls as central demands diminished. Implications and future directions of the results are discussed.