Studied the performance of 57 undergraduates on the Stroop Color-Word Test in 4 experiments. The degree of interference with color naming produced by a word used as the base item was greater when the word was concurrently being held in memory for later recall than when unrelated words were being remembered. Increased interference was also found when the base word in the Stroop task was the category name for a set of words being remembered. Interference declined rapidly within the 1st 15 sec. after presentation when either the presented words or their category name were used as base items in the color-naming task. Some evidence for a longer term trace (up to 50 sec.) was also found. Results support the contention that the category designation of a word is activated as part of the word's encoding. (20 ref.) (PsycINFO Database Record (c) 2006 APA, all rights reserved)