Dual coding under conditions of second stimulus modality uncertainty in successive matching tasks.

Abstract

Subjects matched successively presented stimuli within and across modalities. In conditions in which they were informed of the modalities of the two stimuli, no differences in matching performance were obtained between the four types of match (visual-visual, auditory-auditory, visual-auditory, and auditory-visual). Thus, there appeared to be no difference between the modalities in ability to perceive or retain the particular stimuli used. In conditions in which subjects were informed of the modality of the first stimulus but only of the modality in which the second stimulus would appear on 80% of trials, there was again no significant difference between auditory-auditory and visual-visual matching. However, auditory-visual matching was much faster than visual-auditory matching when the second stimulus appeared in the unexpected modality. The results suggest that subjects prepare for both possible types of match when uncertain of the second stimulus modality and that the cross-modal asymmetry reflects the additional attentional load that this incurs.