When practice makes imperfect: Debilitating effects of overlearning.

It was hypothesized that as overlearning leads to "mindlessness," the individual components of a task become relatively inaccessible to consciousness and therefore unavailable to serve as evidence of task competence. This may lead to a decrement in performance if circumstances, for example, a label connoting relative inferiority, lead one to question one's ability. This was tested in the first experiment by varying practice on a task (no practice, moderate practice, and overpractice) by label assigned to subjects (no label, assistant, boss). As predicted, performance decrements resulted for the no practice and overpracticed subjects who were assigned the inferior status label but not for the moderate practice subjects for whom the task components were still salient. In a second experiment it was found that the debilitation could be prevented for an overlearned task by making components of the task salient. Implications for the vulnerability of experts to these performance debilitations are explored.