A psychophysical investigation of differences between synchrony and temporal order judgments.
BACKGROUND
Synchrony judgments involve deciding whether cues to an event are in synch or out of synch, while temporal order judgments involve deciding which of the cues came first. When the cues come from different sensory modalities these judgments can be used to investigate multisensory integration in the temporal domain. However, evidence indicates that that these two tasks should not be used interchangeably as it is unlikely that they measure the same perceptual mechanism. The current experiment further explores this issue across a variety of different audiovisual stimulus types.


RESULTS
Participants were presented with 5 audiovisual stimulus types, each at 11 parametrically manipulated levels of cue asynchrony. During separate blocks, participants had to make synchrony judgments or temporal order judgments. For some stimulus types many participants were unable to successfully make temporal order judgments, but they were able to make synchrony judgments. The mean points of subjective simultaneity for synchrony judgments were all video-leading, while those for temporal order judgments were all audio-leading. In the within participants analyses no correlation was found across the two tasks for either the point of subjective simultaneity or the temporal integration window.


CONCLUSIONS
Stimulus type influenced how the two tasks differed; nevertheless, consistent differences were found between the two tasks regardless of stimulus type. Therefore, in line with previous work, we conclude that synchrony and temporal order judgments are supported by different perceptual mechanisms and should not be interpreted as being representative of the same perceptual process.
School of Psychology, University of Glasgow, Glasgow, United Kingdom. love.a.scott@gmail.com
Scott A
SA
Love
Karin
K
Petrini
Adam
A
Cheng
Frank E
FE
Pollick
D000161:Acoustic Stimulation / Q000523:psychology; D000328:Adult; D001307:Auditory Perception / Q000502:physiology; D003463:Cues; D005260:Female; D006801:Humans; D007600:Judgment / Q000502:physiology*; D008297:Male; D010775:Photic Stimulation; D013997:Time Factors; D013998:Time Perception / Q000502:physiology; D014796:Visual Perception / Q000502:physiology; D055815:Young Adult