Examined 2 explanations of the Stroop color-naming effect: (a) the form of the word and the color of the ink contact memory in parallel, causing covert response competition when they elicit different color names; and (b) color words distract from the ability to input or to encode ink color. In a mixed-list design, latencies of color-naming responses of 18 undergraduates were taken for individual stimuli falling into 4 categories: (a) in Condition S, the word and color name were the same; (b) in D, the word named a different color; (c) in N, the word was neutral with respect to color; (d) in C, the stimulus was a nonword. Compared to Condition C, S responses showed facilitation, D showed interference, and N showed no effect. The facilitation in Condition S is predicted by the hypothesis that the Stroop effect is due to response competition rather than encoding interference. (PsycINFO Database Record (c) 2006 APA, all rights reserved)