United we fall: All-or-none forgetting of complex episodic events

Abstract

<p>Do complex event representations fragment over time or are they, instead, forgotten in an all-or-none manner? For example, if we met a friend in a café and they gave us a present, do we forget the constituent elements of this event (location, person and object) independently, or would the whole event be forgotten as one? Research suggests that item-based memories are forgotten in a fragmented manner. However, we do not know how more complex episodic, ‘event-based’ memories are forgotten. We assessed both retrieval accuracy and dependency – the statistical association between the retrieval successes of different elements from the same event – for complex events. Across 4 experiments, we show that retrieval dependency is found both immediately after learning and following a 12-hour and 1-week delay. Further, the amount of retrieval dependency after a delay is greater than that predicted by a model of independent forgetting. This dependency was only seen for coherent ‘closed-loops’, where all pairwise associations between locations, people and objects were encoded. When ‘open-loops’ were learnt, where only two out of the three possible associations were encoded, no dependency was seen immediately after learning nor after a delay. Finally, we also provide evidence for higher retention rates for closed-loops than open-loops. Therefore, closed-loops do not fragment as a function of forgetting, and are retained for longer than open-loops. Our findings suggest that coherent episodic events are not only retrieved, but also forgotten, in an all-or-none manner.</p>

Feature-specific reaction times reveal a semanticisation of memories over time and with repeated remembering

“…All recall trials were sorted into four categories, depending on whether participants remembered both features, only perceptual features, only conceptual features, or none. In line with previous work (Balaban et al, 2020;Joensen, Gaskell & Horner, 2018), we expected that over time, the majority of items would be forgotten in a holistic manner, such that items that were fully remembered ("both features correct") on day 1 would be fully forgotten ("none correct") on day 2. For the present purpose, we were however particularly interested in the two response categories indicating partial remembering (i.e., "conceptual only" and "perceptual only" recall trials).…”

Tracking the emergence of location-based spatial representations in human scene-selective cortex

“…A further possibility is that the overlapping content in the overlap condition (relative to the no-overlap condition) supports a more complex A1-AX and A2-AX representation (where X is the overlapping scene in the centre of the panorama). Presentation of A1 cues the retrieval of AX and subsequently A2 (similar in nature to AB-AC inference paradigms; see Horner & Burgess, 2014;Joensen et al, 2019;Schlichting, Mumford, & Preston, 2015;Schlichting, Zeithamova, & Preston, 2014;Zeithamova, Dominick, & Preston, 2012). Representations that encode these transitive relationships between scenes are possible and may support spatial navigation, yet they are not directly predicted by some models of spatial memory (Bicanski & Burgess, 2018;Byrne et al, 2007).…”