Temporal perception does not always correspond to objective time. Several factors contribute to distort perceived timing of stimuli. This work investigates the effect of repeated stimulus presentation (either a sound or a light) on perceived timing of a subsequent audiovisual pair. At the beginning of each trial, a series of sounds or lights is presented with a constant interval. One final stimulus is presented either rhythmically or with a temporal shift. In a psychophysical task, participants judged whether the last stimulus in the sequence is presented before or after a temporal probe in the other modality. Results indicate two types of effects. First, the last stimulus of the sequence appears to be delayed with respect to the probe in the other modality. Second, deviations from regular rhythm tend to be perceptually compensated. Overall, perceived stimulus timing is shown to be affected by the temporal context, and the effect is consistent with a change in perceptual latency. The change depends on the modality of the repeated stimulus and can be explained as a combined effect of an temporal adaptation (i.e., slowing down perception) plus a temporal expectation acting on the slightly arrhythmic stimuli.
Massimiliano Di Luca
Massimiliano Di Luca and Alice R. Fawdrey
Edited by Argiro Vatakis, Fuat Balcı, Massimiliano Di Luca and Ángel Correa
Contributors are: Patricia V. Agostino, Rocío Alcalá-Quintana, Fuat Balcı, Karin Bausenhart, Richard Block, Ivana L. Bussi, Carlos S. Caldart, Mariagrazia Capizzi, Xiaoqin Chen, Ángel Correa, Massimiliano Di Luca, Céline Z. Duval, Mark T. Elliott, Dagmar Fraser, David Freestone, Miguel A. García-Pérez, Anne Giersch, Simon Grondin, Nori Jacoby, Florian Klapproth, Franziska Kopp, Maria Kostaki, Laurence Lalanne, Giovanna Mioni, Trevor B. Penney, Patrick E. Poncelet, Patrick Simen, Ryan Stables, Rolf Ulrich, Argiro Vatakis, Dominic Ward, Alan M. Wing, Kieran Yarrow, and Dan Zakay.
Min Susan Li, Darren Rhodes and Massimiliano Di Luca
An isochronous sequence is a series of repeating events with the same inter-onset-interval. A common finding is that as the length of a sequence increases, so does temporal sensitivity to irregularities — that is, the detection of deviations from isochrony is better with a longer sequence. Several theoretical accounts exist in the literature as to how the brain processes sequences for the detection of irregularities, yet there remains to be a systematic comparison of the predictions that such accounts make. To compare the predictions of these accounts, we asked participants to report whether the last stimulus of a regularly-timed sequence appeared ‘earlier’ or ‘later’ than expected. Such task allowed us to separately analyse bias and performance. Sequences lengths (3, 4, 5 or 6 beeps) were either randomly interleaved or presented in separate blocks. We replicate previous findings showing that temporal sensitivity increases with longer sequence in the interleaved condition but not in the blocked condition (where performance is higher overall). Results also indicate that there is a consistent bias in reporting whether the last stimulus is isochronous (irrespectively of how many stimuli the sequence is composed of). Such result is consistent with a perceptual acceleration of stimuli embedded in isochronous sequences. From the comparison of the models’ predictions we determine that the improvement in sensitivity is best captured by an averaging of successive estimates, but with an element that limits performance improvement below statistical optimality. None of the models considered, however, provides an exhaustive explanation for the pattern of results found.