Browsing by Author "McFeaters, Corinna D."

Now showing 1 - 2 of 2
  • Thumbnail Image
    Item
    Expectation expands subjective duration for repeated stimuli by altering perception
    (American Psychological Association, 2019) McFeaters, Corinna D.; Voyer, Daniel
    Repeated stimuli are generally perceived to be shorter in duration than novel stimuli. Matthews (2015), however, demonstrated that when repetition is predictable, expectations of repetition may expand subjective duration for repeated stimuli. Although this effect is hypothesised to be perceptual, this has yet to be empirically established. The present study, therefore, examined perceptual and decisional factors in the repetition effect by using psychophysical methods while varying probabilities of repetition, in addition to replicating Matthews’ original paradigm. Using faces with neutral expressions, 60 participants completed 2 judgment tasks, indicating whether a comparison stimulus was longer or shorter in duration than a standard stimulus preceding it. Comparison stimuli were presented for the same duration as the 500-ms standard in the replication task and for 1 of 7 durations (from 200–1,250 ms) in the crucial extension task, allowing for examination of sensitivity and bias. No evidence of bias was observed, but modulating participants’ expectations of repetition affected perception, such that discrimination was more difficult under high than low repetition conditions. Overall, participants were more likely to judge stimuli that met expectations as longer, regardless of whether the expectation was repetition or novelty. Implications for models of repetition, context effects, and time estimation are discussed.
  • Thumbnail Image
    Item
    Time flies when you're surprised: exploring expectation's influence on the repetition effect for time perception
    (University of New Brunswick, 2021) McFeaters, Corinna D.; Voyer, Daniel
    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.