The Effect of Modality on Retrieval of Subjective Duration from Long-term Memory

It was examined whether stimulus modality (auditory vs. visual) affects the retrieval of subjective duration from memory. In 2 experiments a temporal generalization paradigm was used. Participants had to decide whether the previously learned standard duration (400 ms) occurred in the context of comparison stimuli. Two major results were found. (1) Performance was unaffected by the modality of the training phase, but (2) was biased if both modality of learning and modality of testing were different. Then, judged duration “lengthened”, i.e., temporal generalization gradients (the proportion of identifications of a stimulus as the standard, plotted against stimulus duration) shifted to the right. The observed shift is interpreted as a result of a delayed timing process. Data from studies of human subjective time indicate that judgement of the duration of a stimulus is determined not only by objective duration but is also influenced by non-temporal stimulus features. Frequently replicated was the finding that duration estimation is affected by stimulus modality. Two features of the effect of stimulus modality on duration judgement have already been discovered. First, auditory stimuli are usually judged to be longer than visual stimuli of physically equal duration (e. g. Goldstone & Goldfarb, 1964; Goldstone & Lhamon, 1974; Sebel & Wilsoncroft, 1983). Second, auditory intervals are judged with greater accuracy than visual intervals (e. g. Collier & Logan, 2000; Glenberg, Mann, Altman, Forman, & Procise, 1989; Rousseau & Rousseau, 1996; Wearden, Edwards, Fakhri, & Percival, 1998). Common to most explanations of the modality effect is the assumption that the cause for modality-specific differences in judging a time interval should be located at relatively early stages of central information processing (e. g. encoding or internal clock). However, relatively little importance has been directed to the question whether duration values of auditory and visual stimuli are represented differentially in humans’memory (see Hocherman & Ben-Dov, 1979, as an exception). The topic of the present study was to examine whether stimulus modality affects the retrieval of subjective duration from long-term memory. Here, long-term memory refers to a memory that stores values of duration for the period of the whole task that is used.