The locus of semantic interference in the 'Stroop' color-naming task

In two experiments, introductory psychology students responded in two ways to three lists of 60 words printed in different colors. The lists consisted of color words and two sets of words associated with the colors (e.g., SKY, BLOOD, etc.). When the subjects responded by naming the color in which each word was printed, it took longer for the color word list than for either list of associates, i.e., the classical Stroop interference effect. The other response required the subjects to say words from one of the association lists which corresponded to the color in which each word was printed, e.g., they saw the word BLACK (or NIGHT, or COAL) printed inred ink, and had to respond by saying “blood.” Using this response, it took longest for the subjects to complete the list of words which were the same as those required as responses. Color words were somewhat less difficult, and the other association words were completed most quickly. The results do not pinpoint the locus of interference, but clarify additional assumptions which must be accepted to maintain alternative hypotheses.