On the impact of event boundaries on memory for recently encountered information.

摘要

To perceive and understand everyday activities, observers perceptually segment activities into events, separating what has just happened from what is happening now. One recent theory suggests that event segmentation acts as a control process that regulates when internal, active representations of the current event are reset and updated with new information. If this is the case, then information from the previous event must be retrieved from episodic memory regardless of the amount of time that has passed since it was encountered. This dissertation examined this hypothesis in four experiments. For these experiments, participants watched commercial movies that presented objects within the context of everyday, goal-directed activities. Five seconds after an object was presented, the movie briefly stopped for a two-alternative, forced-choice object recognition test. Objects could be presented during an event boundary (distinguishing between boundary objects and nonboundary objects) and, depending on whether an event boundary occurred during the delay between object presentation and test, objects could be tested in the same event in which the object was presented or in a new event. In all experiments, recognition memory varied with the type of object test. Performance was generally better for boundary objects than for nonboundary objects. This difference was magnified when the objects were tested in a new event rather than in the same event. Conceptual and perceptual memory for objects in an event were examined in two separate experiments which revealed that memory for event boundaries is mainly conceptual in nature, but also consists of memory for the perceptual features of fixated objects. Finally, functional neuroimaging data provided evidence that attempting to retrieve information across event boundaries engages episodic retrieval systems, including the medial temporal lobes. These data provide strong support for the conclusion that perceptual event segmentation is associated with what information is remembered about an event as well as changes in how recently encountered information is maintained in memory.