Mind the gap: Temporal discontinuities in observed activity streams influence perceived duration of actions.

In everyday life, when observing activities taking place in our environment, we often shift our attention among several activities and therefore perceive each activity sequence piecemeal with temporal gaps in between. Two studies examined whether the length of these gaps influences the processing of the observed activities. Experiment 1 presented film clips depicting activities that were interrupted by either short or long gaps and asked participants to estimate how long the target action presented at the end of the clip would normally take if it were to take place in reality. Using the same activities, Experiment 2 asked participants to judge the duration of the presentation of this target action-that is, how long the target action was presented. Results showed that following long gaps instead of short gaps, target actions are estimated to take longer in reality (Experiment 1), but the depictions themselves are estimated to be shorter (Experiment 2). Following long gaps, target actions seem to be processed pars pro toto as placeholders for longer segments in the stream of events, but in contrast, the depictions themselves appear to be shorter. Results suggest that long gaps lengthen the perceived duration of an event in our cognitive representation and also seem to influence our perception of the duration of the presentation itself.