Is the Anti-Saccade Task a Valid Measure of Inhibition?

Research on individual differences in executive functions has often used a manual version of the anti-saccade task to measure cognitive inhibition. Here, we investigated the validity of anti-saccade performance as a measure of inhibition. Success in this task relies on several processes: Inhibition of a saccade to the cue location; translating the cue location into the target location; making a saccade to the target location; and rapid identification of the target stimulus. In two experiments (NE1 = 181 and NE2 = 165) we varied whether the task required these processes. We also varied the preparation time before each trial, and the cue-target interval to measure the speed of task-relevant processes. We used a theoretically motivated statistical model to dissociate parameters that reflect the contribution of each process to performance. Individual differences in most of these parameters correlated with observed performance, implying that performance reflects a mixture of several processes. Critically, inhibition accounted for a small proportion of variance in performance. Only the efficiency of translating cue information into the target location was credibly correlated with working-memory capacity and processing speed. These results question the validity of anti-saccade performance as a measure of inhibition.