Temporal proximity affects the detailed recall of events in a nested hierarchy

Retrieved-context models of memory posit that a slowly drifting neural context signal is encoded alongside items in memory. However, this signal can be disrupted by event boundaries, affecting the temporal relationships between items across event boundaries. Here, we investigated how temporal proximity and event boundaries affect the detailed recall of events. Specifically, we assessed memory for events in the movie Forrest Gump, chosen specifically because of its hierarchical event structure with individual events in the movie being nested within broader life-periods (e.g., childhood, college, etc.). Importantly, the trial order at recall was structured such that adjacent trials tested events that were (1) either temporally close or far and (2) either within or across a life period. Participants provided both more event-specific details and more false memories for an event when the preceding event came from the same life period, suggesting that recall of the life period supported recall of episodic information, but also increased the likelihood of providing false information. Further, participants provided more intrusions from non-cued events after just recalling an event that was temporally distant, with this effect exacerbated if the preceding event was also across a life period boundary. Quantifying event similarity between the cued event and the sources of intrusions suggests that participants may be providing supplementary information to help scaffold memory for the cued event. Altogether, these results demonstrate that both temporal proximity and event boundaries affect detailed memory recall, extending previous findings into the domain of naturalistic events.