MARKERS INFLUENCE ON THE DURATION DISCRIMINATION OF INTERMODAL INTERVALS

The effects of sensory signal characteristics on the duration discrimi nation of intermodal intervals was investigated in three experiments. Temporal intervals were marked by either the successive presentation o f a visual then auditory signal (VA), or by the successive presentatio n of an auditory then visual signal (AV). The results indicated that(1 ) VA intervals are generally easier to discriminate than are AV interv als, but this effect depends on the range of duration studied; (2) AV intervals are perceived as longer than VA intervals for durations rang ing from 250 to 750 msec; (3) the intensity of the visual markers for both AV and VA intervals does not affect the discrimination; and (4) t he perceived duration of an intermodal interval is influenced by the l ength of the first and second markers. The results are mainly interpre ted in terms of (1) a sensory trace left by visual and auditory signal s and (2) the detection of these signals.