RESTRICTED ATTENTIONAL CAPACITY WITHIN BUT NOT BETWEEN SENSORY MODALITIES

Restrictions to attentional capacity are revealed by the interference that commonly results when two sensory inputs must be identified at th e same time(1). To investigate this phenomenon within and between moda lities, we presented streams of visual and/or auditory inputs, contain ing occasional targets to be identified and recalled. For two visual o r two auditory streams, identification of one target produced a sustai ned reduction in the ability to identify a second, the period of inter ference lasting for several hundred milliseconds. Subjectively, when a ttention was assigned to one target it was temporarily unavailable for another. In contrast, there was no such time-locked interference betw een targets in different modalities, The results suggest a modality-sp ecific restriction to concurrent attention and awareness; visual atten tion io one simple target does not restrict concurrent auditory attent ion to another.