The effect of an irrelevant directional cue on choice reaction time: Duration of the phenomenon and its relation to stages of processing

Two experimental paradigms were used to investigate the interference which occurs in a choice RT task when the source of a stimulus does not correspond with its meaning. In one paradigm, subjects were instructed to delay executing their response to a red or green light until they heard a go signal which was presented 0, 150,250, or 350 msec after the light. In the other paradigm, subjects translated the pitch of a tone into an appropriate keypress response. For some groups, the stimulus response connections were specified prior to or simultaneously with the presentation of the stimulus tone, while, for other groups, the labeling of the response keys followed the onset of the tone. Results indicated that irrelevant directional cues produce interference which affects the response selection stage and persists for approximately 250 msec