Duration Illusions in a Train of Visual Stimuli

Abstract

The first stimulus in a sequential train of identical flashes of light appears to last longer than those in the middle of the train. Four flashes (each 600 or 667 ms) were presented and the first was shortened until it appeared to have the same duration as that of the next. The duration of the first stimulus was found to be overestimated by about 50%. The illusion was unaffected by stimulus contrast, size, or interflash interval (between 100 and 600 ms). For some subjects, the last stimulus in the train also appeared to be about 50% longer than the penultimate flash. The results are discussed in terms of theories of how attention, arousal, and stimulus processing can affect duration perception. The mechanisms activated are peculiar to the visual system, since no similar illusion of duration was consistently experienced with a train of auditory tones.

Action, arousal, and subjective time

“…The first and last stimuli in a train of four squares of light undergo a very large temporal bias, but manipulations that would be predicted to modulate arousal (e.g. stimulus intensity) do not affect this illusion (Rose et al, 1995). The duration of a vibrating stimulus touched following an arm movement is overestimated relative to subsequent reference stimuli, but this effect does not (always) extend to judgements about visual stimuli (Yarrow et al, 2003).…”

“…They presented data demonstrating that a period demarcated by a key press (start) and a brief tone (end) was overestimated when it contained a shift of auditory spatial attention. They also discussed an earlier finding that the first and last stimuli in a train of four identical squares of light are perceived to have an extended duration relative to the middle two (Rose & Summers, 1995). Arousal was proposed to account for all three illusions.…”

Humans don’t time subsecond intervals like a stopwatch.

“…Of particular concern here, the order of two judged intervals is well known to affect relative judgements about duration (the so called "time order error"; see Hellstroem, 1985, for review) and additional substantial position-dependent biases emerge for short trains of >2 stimuli (e.g. Nakajima, Hoopen, & Van der Wilk, 1991;Rose & Summers, 1995).…”

“…Rose & Summers, 1995) and thus ignore the data regarding accuracy, the magnitude of the increase in judgement uncertainty (particularly prominent in the long-split condition) deviated significantly from model predictions in…”

Minding time in an amodal representational space

“…click train) or events at a faster rate are judged longer than an empty interval or an interval containing less or slower discrete elements, respectively ( Fraisse 1957;Goldstone & Lhamon 1976). Numerous cases of subjective time distortions ('dilation' when objective time is overestimated, 'compression' when it is underestimated) have recently been reported using different paradigms across sensory and motor modalities (Rose & Summers 1995;Yarrow et al 2001Yarrow et al , 2004Hodinott-Hill et al 2002;Sasaki et al 2002;Park et al 2003;Tse et al 2004;Morrone et al 2005;van Wassenhove et al 2008). For example, an oddball within a stream of standard events of identical duration is perceived as longer than a standard event ( Tse et al 2004).…”