Proceedings of the Annual Meeting of the Cognitive Science Society

Events are considered as temporal segments with a beginning and an endpoint. Philosophical and linguistic literature on events distinguishes between bounded events that include distinct temporal stages leading to culmination (e.g., fix a car) and unbounded events that include largely undifferentiated stages and lack an inherent endpoint (e.g., drive a car). The present study shows that event viewers spontaneously compute this distinction through an interruption detection task. People watched videos of bounded or unbounded events with a visual interruption lasting .03s at the midpoint or close to the endpoint of the event stimulus. People indicated whether they saw an interruption after each video (Experiments 1) or responded as soon as possible during each video (Experiment 2). In both cases, the endpoint-midpoint difference depended on whether participants were watching a bounded or an unbounded event. As people perceive dynamic events, they spontaneously track boundedness, or the internal temporal structure of events.