Effects of motor and verbal practice on the Stroop task.

Motor responses to the Stroop task have been largely ignored despite almost a century of active research on verbal responses to the test. The Stroop task maximizes verbal interference by asking subjects to ignore the stimulus word, e.g., red, and respond to the color of the ink in which the work is printed, e.g., blue. A few recent studies have suggested that motor responses (pressing color-coded buttons) might minimize this interference phenomenon presumably via bypassing the usual verbal processing mechanisms. This study compared motor and verbal responses and provided extensive practice. There were no over-all significant differences between motor and verbal responding although motor responses were faster. Significant practice effects and a significant interaction of response mode by practice suggest that motor responding reacts more rapidly to practice effects.