Overcoming Stroop interference: the effects of practice on distractor potency.

With practice, do distracting stimuli lose their ability to distract? In a series of experiments, subjects practiced counting digits, a task subject to Stroop-type interference, and then were tested in a variety of transfer conditions. The results indicate that digits do lose their ability to distract as a result of practice but that this loss is highly specific; practice in ignoring one pair of distractors (2 and 4) does not improve later performance when ignoring a different pair (1 and 3). However, this practice effect does transfer to distractor stimuli having the same meaning as the stimuli ignored in practice (TWO and FOUR, but not TO and FOR). The results can be explained either in terms of active learning to suppress distraction or in terms of habituation of competing responses.