Temporal order judgement for auditory and visual stimuli.

The ability to perceive temporal order for pairs of auditory and visual stimuli was investigated in 12 volunteers. They were asked to make judgements about the order of presented stimuli by pressing two response buttons in a certain order. The performance on auditory and visual tests was studied in relation to the Inter-Stimulus-Interval (ISI), which varied from 5 to 500 ms. In general, the level of performance was similar for the two modalities and the criterion of 75% of correct responses was reached at ISI longer than 40 ms, independently of the modality. These findings are consistent with previous research. However, at ISI of 5 ms, a significantly higher level of correctness was observed for the auditory than visual task. Such a tendency was also observed for ISIs of 10, 20 and 40 ms. Better processing in the auditory compared to the visual task at shorter ISIs may result from a different kind of transduction mechanism at the level of receptive cells in each modality. Alternatively, subjects may use two different kinds of response strategies in the auditory modality, only one being comparable to the response strategy in the visual modality.