The Role of Selective Attention in Cross-modal Interactions between Auditory and Visual Features

Evans and Treisman (2010) showed systematic interactions between audition and vision when participants made speeded classifications in one modality while supposedly ignoring another. We found perceptual facilitation between high pitch and high visual position, high spatial frequency and small size, and interference between high pitch and low position, low spatial frequency and large size, while the converse was the case between low pitch and the same visual features. The present study examined the role of selective attention in these cross-modal interactions. Participants performed speeded classification or search tasks of low or high load while attempting to ignore irrelevant stimuli in a different modality. In both paradigms, congruency between the visual and the irrelevant auditory stimulus had an equal effect in the low and in the high perceptual load conditions. A third experiment tested divided attention, requiring participants to compare stimuli across modalities and respond to the visual-auditory compound. The congruency effect was as large with attention focused on one modality as when it was divided across both. These findings offer converging evidence that cross-modal interactions between corresponding basic features are independent of selective attention.