Interference effects on verbal and motor responding

Twenty psychology students from California State University, Northridge, served as subjects in an experiment designed to determine differential interference effects with verbal and motor responding. Responses were made to Stroop color-word stimuli (i.e., the word red printed in blue ink) which requires subjects to make responses based on conflicting information. Subjects were asked to ignore what the word spelled and to respond only to the color of the ink. For purposes of this study, Stroop color-word stimuli were placed on slides containing four color-words per slide. Ten subjects were placed in a motor response group and 10 were placed in a verbal response group. Motor responders indicated the color of the ink they saw by using an appropriately coded response box while verbal responders indicated the color of the ink they saw by verbal report. Both groups were exposed to 200 slide presentations broken down into trials and blocks of trials. Research indicated that motor responses in general tend to be minimally effected by interference while practice promotes minimal improvement in verbal responses made to Stroop color-word stimuli. Investigations concerned with how Stroop color-word interference interacts with these two research areas was found to be scarce and their findings inconclusive. (See more in text.)