EFFECTS OF VISUAL AND AUDITORY NOISE ON VISUAL CHOICE REACTION-TIME IN A CONTINUOUS-FLOW PARADIGM

Two experiments were employed to investigate the processing speed of a visual target surrounded by visual noise (e.g., HHSHH or SSSSS) and auditory location cues (e.g., a left- or right-positioned tone) in a binary choice reaction time (RT) task. Visual noise impaired processing speed when it was incongruent with the target (e.g., HHSHH and SSHSS). Irrelevant location cues impaired reaction speed when the location of the tone did not correspond with the location of the correct response. When the visual stimuli were characters, the visual and auditory noise sources made additive contributions to mean visual choice RT. It was concluded therefore that visual congruity and location correspondence affect different process elements, response activation and response selection, respectively. This conclusion must be qualified, however, in that when the visual stimuli were left- or right-pointing arrows (e.g., .rarw..rarw..rarw..rarw..rarw. or .rarw..rarw..fwdarw..rarw..rarw.), congruity and correspondence interacted. This interaction is interpreted to suggest that when visual and auditory noise are the same type (i.e., eliciting a left or right association) a cross talk between visual and auditory feature-detection channels might occur to produce a perceptual conflict on corresponding trials.