The efficiency of cognitive inhibition was contrasted in children diagnosed
with ADHD and a control group of age- and IQ-matched average children. Two
tasks were used to measure inhibitory ability: the negative-prime Stroop t
ask and a directed-forgetting memory task. Based on contemporary theoretica
l perspectives that postulate deficits in inhibitory function in the ADHD p
opulation, it was predicted that ADHD children would be significantly less
efficient inhibitors than the average children. Contrary to predictions, ho
wever, ADHD children showed no deficits in inhibitory abilities compared to
controls. Average children were faster on the second administration of the
Stroop task, whereas ADHD children were slower. These results were interpr
eted within the framework of the inhibition models. It was proposed that di
fferences in inhibitory abilities, such as the ones tapped here, may appear
earlier than age 8, and that the engaging aspects of tasks may have optimi
zed the ADHD children's performance. The slower performance of the ADHD gro
up on the second administration of the Stroop task is consistent with the h
ypothesis that although ADHD children can inhibit, they find it more effort
ful to do so than do average children.