Simultaneous motor and verbal processing of visual information in a modified Stroop test

Color patches could simultaneously be manually counted and conflicting color words named in the time required for one of the tasks alone. The independence of verbal and nonverbal information processing resembles “split-brain” behavior. Naming color patches while counting color words took more time than would have been required for doing the individual tasks successively, indicating response competition in the standard Stroop test. Form or location stimuli substituted for color words reduced interference when naming color patches.