Temporal order memory in naturalistic events is scaffolded by semantic knowledge and hierarchical event structure

Remembering the temporal dynamics of past experiences help people plan for the future.Previous studies using discrete pictorial stimuli showed that people are better at remembering thetemporal order of items occurring within the same perceptual context than items spanning acrossa contextual boundary, suggesting that event segmentation can structure temporal order memoryby resetting item-level binding mechanisms. However, in meaningful everyday scenarios othermechanisms may play equal or greater roles. Hierarchical event structure and knowledge abouttypical temporal order can powerfully scaffold memory reconstruction. In the first twoexperiments, we tested order memory for narratives about everyday activities. We found thatwhen the narratives described activities with semantic constraints on order for fine-grainedactions or for coarse-grained activity units, participants could use these to improve order memoryafter both short (2.5-minute) and longer (20-minute) delays. A third experiment revealed thatserial recall was chunked based on coarse-level event membership and that semantic orderconstraints helped organize recall order. A final experiment showed that even in the absence ofsemantic constraints on coarse-grained activity, participants could use episodic memory forcoarse-grained order to constrain memory for fine-grained order. Collectively, these resultsprovide evidence for important roles played by hierarchical event structure and prior knowledgein scaffolding reconstructive memory, indicating that reconstructive memory processes usemultiple sources of information in addition to simple episodic associations between fine-grainedunits.