Narratives bridge the divide between distant events in episodic memory

Many studies suggest that information about past experience, or episodic memory, is divided into discrete units called “events.” Paradoxically, we can often remember experiences that span multiple events. Events that occur in close succession might simply be bridged because of their proximity to one another, but many events occur farther apart in time. Intuitively, some kind of organizing principle should enable these temporally-distant events to become bridged in memory. We tested the hypothesis that episodic memory exhibits a narrative-level organization, enabling temporally-distant events to be better remembered if they form a coherent narrative. Furthermore, we tested whether a post-encoding consolidation process is necessary to integrate temporally-distant events. Participants learned and subsequently recalled events from fictional stories, in which pairs of temporally-distant events involving side-characters (“sideplots”) either formed one coherent narrative or two unrelated narratives. In three experiments, participants were cued to recall the stories either immediately, after a 24-hour delay, or after a 12-hour delay which elapsed during daytime (“wake”) versus nighttime (“sleep”). Participants recalled more information about coherent than unrelated narrative events, in most delay conditions, and the delay and sleep manipulations indicated that post-encoding consolidation was not necessary to integrate temporally-distant narrative events. Post-hoc modeling across experiments suggested that sentence-level semantic similarity could not solely account for the coherence benefit. This reliable memory benefit for coherent narrative events supports theoretical accounts which propose that higher-order semantic structures scaffold episodic memory.