Investigation of age-related differences in an adapted Hayling task

The Hayling task is traditionally used to assess activation and inhibitory processes efficiency among various populations, such as elderly adults. However, the classical design of the task may also involve the influence of strategy use and efficiency of sentence processing in the possible differences between individuals. Therefore, the present study investigated activation and inhibitory processes in aging with two formats of an adapted Hayling task designed to reduce the involvement of these alternative factors. Thirty young adults (M=20.7 years) and 31 older adults (M=69.6 years) performed an adapted Hayling task including a switching block (i.e., unblocked design) in addition to the classical task (i.e., blocked design), and the selection of the response between two propositions. The results obtained with the classical blocked design showed age-related deficits in the suppression sections of the task but also in the initiation ones. These findings can be explained by a co-impairment of both inhibition and activation processes in aging. The results of the unblocked Hayling task, in which strategy use would be reduced, confirmed this age-related decline in both activation and inhibition processes. Moreover, significant correlations between the unblocked design and the Trail Making Test revealed that flexibility is equally involved in the completion of both sections of this design. Finally, the use of a forced-response choice offers a format that is easy to administer to people with normal or pathological aging. This seems particularly relevant for these populations in whom the production of an unrelated word often poses problems.