Abstract
Temporal synchrony is the perception of simultaneity from sensory inputs that may not necessarily be simultaneous. We sought to determine whether there were differences in perceived temporal synchrony between a continuous audiovisual stream and a discrete audiovisual event. We also determined whether the audiovisual stream and the audiovisual event interacted with each other when presented simultaneously. Five participants viewed either a 3-second 1 Hz sinusoidally oscillated audio visual stream, a 167 msec audio visual event, or a combination of both. The audiovisual stream consisted of white noise and a grating; the intensity of the white noise and the contrast of the grating oscillated between 10% and 40%. The audiovisual event consisted of white noise and a grating at 100% intensity and contrast. The audio and visual components of both the stream and the event were temporally offset by ±300, ±233, ±150, ±83, or 0 msec. Participants judged the synchrony of the audiovisual stream, the audiovisual event, or both depending on what was present in that particular trial. The data showed that when presented alone, participants were more sensitive to temporal offsets in an audiovisual event than in an audiovisual stream. When presented with an audiovisual stream, participants were less sensitive to the temporal offsets in the audiovisual event and the synchrony of the audiovisual stream itself did not influence the perception of the audiovisual event's temporal synchrony. However, when presented with an audiovisual event, participants were not less sensitive to the temporal offsets in the audiovisual stream. Also, there was a trend that the perception of temporal synchrony in the audiovisual stream was biased towards the temporal synchrony of the audiovisual event. These data support the importance of distinct features as critical determinants of temporal synchrony and show that temporal synchrony information present in two events can influence one another.