Abstract
Temporal processing is frequently performed implicitly, when temporal calculations are required in order to perform a task, whose output is not temporal in essence. One prevalent use of implicit timing is in the formation of temporal expectations, in which the timing of an upcoming event is predicted in order to prepare for its occurrence. The sources of this prediction can be “endogenous”, relying on memorizing the temporal interval between the expected event and a preceding reference event, measuring the time from the onset of the reference, and increasing preparedness when the expected interval elapses. However, temporal expectations can also be “exogenous”, namely based on extracting temporal information from the ongoing temporal dynamics of the input, rather than memory-dependent. One unique case of such temporal dynamics is when the input is isochronous (i.e., stimuli appear rhythmically, with fixed inter-onset-interval), such as in biological motion, speech, or music. Based on findings from auditory rhythms, it has been suggested that in such case, expectations are realized by synchronization of internal oscillators to the input periodicity, a process that encompasses both the representation of the interval and the application of expectation at the correct time. In two studies, we investigate temporal expectations created in visual rhythmic context, showing that they have unique cognitive and electrophysiological characteristics, and dissociating them from other types of temporal expectations.
