Features of Stroop and reverse-Stroop interference: analysis by response modality and evaluation.

Stroop interference (the Stroop effect) is the phenomenon observed when naming the color of an incongruent stimulus, such as the word "red" printed in blue ink; typically, this color incongruence causes slower naming compared to a neutral stimulus, such as a blue square patch. Reverse-Stroop interference occurs when reading the stimulus takes longer than reading the neutral stimulus. Features of Stroop and reverse-Stroop interference were examined, focusing on the difference between the response modalities--oral response and manual response--and the difference between methods of evaluating performance (time or correct responses) and the interference score. Participants were 47 students (30 women, 17 men; M age=20.8 yr., range=19-29). The results were as follows: (1) the performance of the reverse-Stroop condition was higher than that of the Stroop condition for both oral and manual responses; (2) the Stroop interference score was significantly greater with the oral response than with the manual response; and (3) the reverse-Stroop interference score was constant regardless of the response modality. The results were discussed with respect to differences in processing speeds of verbal and sensory information.