Cognitive components in perseverative and nonperseverative errors on the object alternation task

Knowledge of response rules in the object alternation (OA) task was experimentally manipulated in 20 alcohol-dependent men and 20 controls. The results suggest that perseverative and nonperseverative errors in OA are under the direct control of task-specific knowledge which must be induced and retained from trial to trial, and that impaired response inhibition is not solely responsible for poor performance on these tasks. The demonstration of a cognitive contribution to poor performance on the OA task suggests that rule induction must be achieved before successful response selection and inhibition can take place. We conclude by discussing implications for our understanding of other delayed response tasks and clinical tests of prefrontal function (e.g., the Wisconsin Card Sorting Test (WCST) and the Halstead Category Test).