Judging the relative duration of multimodal short empty time intervals

Abstract

Three experiments address the cause of the different performance levels found in time discrimination of empty intervals with durations near 250 msec. Performance differed according to the kind of sensory modality that marked the intervals. With a procedure in which the type of marker was randomized from trial to trial, it was shown that variability of discrimination judgments could not be attributed entirely to the variability of the criterion on which a judgment was based. Such a randomization slightly affects discrimination but provokes a reorganization related to marker conditions of the probabilities of judging an interval to be short or long. Moreover, it was shown that within intramodal conditions, physical characteristics of markers influence the discrimination performances. To account for the results generated with different marker-type intervals at 250 msec, we propose that two types of processor may be involved in duration discrimination: one is specifically related to a given sensory modality, whereas the other is aspecific and responsible for discrimination of intermodal intervals.

Duration perception in crossmodally-defined intervals

“…Grondin and Rousseau (1991) found that when a brief beep marked the onset of an interval and a brief light flash marked the offset, the interval was perceived to be longer than when the onset was marked by a light flash and the offset by a beep. Other studies investigating duration judgments reported that simple biases due to perceptual latencies are not sufficient to explain all modality-dependent effects (Ulrich et al, 2006;Wearden, Edwards, Fakhri, & Percival, 1998).…”

“…Following previous work (e.g., Grondin & Rousseau, 1991), the current study uses the biases in temporal perception caused by processing input of different sensory modalities to specify whether there is one modality-independent mechanism or whether multiple mechanisms are involved in processing crossmodal durations. Sensory latencies lead to summative distortion of time.…”

“…Sensory latencies were found to affect duration judgments (Grondin & Rousseau, 1991;Rousseau, Poirier, & Lemyre, 1983;Grondin, Ivry, Franz, Perreault, & Metthè, 1996). Grondin and Rousseau (1991) found that when a brief beep marked the onset of an interval and a brief light flash marked the offset, the interval was perceived to be longer than when the onset was marked by a light flash and the offset by a beep.…”

“…Humans are capable of perceiving durations of less than a second with high precision (e.g., Grondin & Rousseau, 1991). One common concept of the underlying time-keeping system enabling duration judgments is the pacemaker-accumulator model (see Church & Broadbent, 1990, for a review).…”

“…We presented participants with audiovisual, audiotactile, and visualtactile intervals and asked them to compare the intervals to probe durations (see Grondin & Rousseau, 1991). To test whether perceived duration follows a summative or a multiplicative pattern, we fitted a linear regression model to the observed data across five stimulus durations.…”