Free recall is shaped by inference and scaffolded by event structure

Though everyday life is continuous, people understand and remember experiences as discrete events separated by boundaries. Event boundaries influence the temporal structure of memory, and are thought to enhance encoding of boundary-adjacent information. However, the extent to which event boundaries influence memory for specific items, and their effect on memory in interactive environments is not well understood. Here, we designed a task to test how boundaries between hidden rules and uncertainty about those rules affect recall of item-level information. Participants responded to individual word stimuli, with words grouped by rules forming events, and abrupt shifts between rules causing event boundaries. Afterwards, participants freely recalled words from the task. Recall was clustered based on event structure, and contrary to predictions of theories of event cognition, recall was worse for words encoded immediately after event boundaries. These findings indicate that event structure and inference play important roles in shaping episodic memory.