Time flies when you're surprised: exploring expectation's influence on the repetition effect for time perception
University of New Brunswick
Many factors affect the experience of subjective duration. One such factor, immediate repetition, typically results in a subjective contraction of duration for the repeated stimulus, but Matthews (2015) demonstrated that the effect of repetition is modulated by expectations of repetition. Matthews hypothesized a perceptual basis for this effect and proposed a mechanism of action whereby subjective duration is related to the strength of the representation - that is, a stronger representation corresponds to a longer subjective duration - which was later termed the Processing Principle (Matthews & Meck, 2016). Article 1 replicated Matthews' findings and extended them using signal detection methodology to examine the proposed perceptual basis for the effect of expectation. Expectation affected discrimination sensitivity but not response bias, supporting the perceptual hypothesis. The direction of the sensitivity effect, however, suggested that representation for expected repeated stimuli may have been poorer, contrary to the Processing Principle. Implications for our understanding of expectation's effects and their role in related tasks are discussed. Article 2 directly examined the relationship between representation and perceived duration by manipulating the visual clarity of task stimuli in order to weaken the perceptual representation of the stimulus. Although weaker representations should result in shorter subjective durations according to the Processing Principle, stimulus degradation did not affect the relationship between repetition and expectation. Furthermore, perceived duration was uniformly longer, rather than shorter, for trials that contained a degraded stimulus, regardless of trial type, expectation of trial type, or which stimulus of the trial pairs was degraded. The results suggested, however, that participants formed a second, global expectation for degradation, and longer subjective durations for trials with expected degradation could reflect representational sharpening processes at this level. Altogether, findings for Article 2 are not wholly consistent with the Processing Principle, but neither can the relationship between representation and subjective duration be ruled out at this time.