Does Global Slowing Explain Age Effects in Inhibitory Control?

A long-standing debate in the study of cognitive aging centers around the issue of whether aging results in a selective deficit in inhibitory control beyond general slowing of cognitive processing. Previous studies have obtained mixed findings, in part because the typical free-response-time paradigm lacks the specificity required to disentangle component processes underlying inhibitory control. Here, we apply a forced-response paradigm and computational model to test whether aging results in overall speed differences or a selective deficit in inhibitory control. Across two experiments, over 200 older adults and younger adults completed a forced-response arrow-flanker task. We found strong evidence that older adults demonstrate a global slowing of processing without any selective deficit in inhibitory control in this task. Furthermore, we demonstrate that global slowing is sufficient to explain the mixed findings in previous free-response-time studies. Overall, these results argue against a selective inhibitory-control deficit in older adults.