Divided attention between simultaneous auditory and visual signals.
Past studies of simultaneous attention to pairs of visual stimuli have used the "dual-task" paradigm to show that identification of the direction of a change in luminance, whether incremental or decremental, is "capacity-limited," while simple detection of these changes is governed by "capacity-free" processes. On the basis of that finding, it has been suggested that the contrast between identification and detection reflects different processes in the sensory periphery, namely the responses of magno- and parvocellular receptors. The present study questions that assertion and investigates the contribution of central processing in resource limitation by applying the dual task to a situation in which one stimulus is auditory and one is visual. The results are much the same as before, with identification demonstrating the tradeoff in performance generally attributed to a limited capacity but detection showing no loss compared with single-task controls. This implies that limitations on resources operate at a central level of processing rather than in the auditory and visual peripheries.
Bonnel
A M
AM
Centre National de la Recherche Scientifique, Marseille, France. ambonnel@garnet.berkeley.edu
Hafter
E R
ER
D000328:Adult; D001288:Attention / Q000502:physiology; D001307:Auditory Perception / Q000502:physiology; D015350:Contrast Sensitivity; D004193:Discrimination Learning; D006801:Humans; D008144:Loudness Perception; D011601:Psychophysics; D011603:Psychophysiology; D014796:Visual Perception / Q000502:physiology