Time-dependent emotional memory transformation: divergent pathways of item memory and contextual dependency

Abstract

Emotional memory can persist strikingly long, but it is believed that not all its elements are protected against the fading effects of time. So far, studies of emotional episodic memory have mostly investigated retention up to 24h post-encoding, and revealed that central emotional features (items) are usually strengthened, while contextual binding of the event is reduced. However, even though it is known for neutral memories that central versus contextual elements evolve differently with longer passage of time, the time-dependent evolution of emotional memories remains unclear. Hypothetically, compared to neutral memories, emotional item memory becomes increasingly stronger, accompanied by accelerated decay of – already fragile – links with their original encoding contexts, resulting in progressive reductions in contextual dependency. Here, we tested these predictions in a large-scale study. Participants encoded emotional and neutral episodes, and were assessed 30 minutes (N = 40), one day (N = 40), one week (N = 39), or two weeks (N = 39) later on item memory, contextual dependency, and subjective quality of memory. The results show that, with the passage of time, emotional memories were indeed characterized by increasingly stronger item memory and weaker contextual dependency. Interestingly, analyses of the subjective quality of memories revealed that stronger memory for emotional items with time was expressed in familiarity, whereas increasingly smaller contextual dependency for emotional episodes was reflected in recollection. Together, these findings uncover the time-dependent transformation of emotional episodic memories, thereby shedding light on the ways healthy and maladaptive human memories may develop.

Context reexposure to bolster contextual dependency of emotional episodic memory

“…We also observed that memory retrieval was stronger during reexposure to the original encoding context than during exposure to a similar context. These findings replicate earlier studies (Cox, Meeter, et al, 2022;van Ast et al, 2013van Ast et al, , 2014, and show that our basic manipulations were successful. However, we did not find evidence for any of the hypotheses: reexposure to the original encoding context did not promote contextual dependency of memory, nor did exposure to a similar context reduce it.…”

“…In short, inducing relatively strong reliving by reexposure to the encoding context was successful, and no other unexpected effects on reliving were observed. showing context-dependent memory (Cox, Meeter, et al, 2022;Godden & Baddeley, 1975; Smith & Vela, 2001;van Ast et al, 2013van Ast et al, , 2014, and smaller contextual dependency for emotional versus neutral memories (Cox, Meeter, et al, 2022;van Ast et al, 2013van Ast et al, , 2014.…”

“…When one returns to the spatial environment in which an event has previously occurred, retrieval and recognition of that event often happens readily, whereas memories can be more difficult to reach in different contexts (Godden & Baddeley, 1975;Smith, 1979;Smith & Vela, 2001). Such contextual dependency of memory is, however, less pronounced for emotional compared to neutral memories, an observation that is partly attributed to relatively weak embedding of emotional events in their encoding context (Cox, Meeter, et al, 2022;van Ast et al, 2013van Ast et al, , 2014. The reduced contextual dependency of emotional memory is believed to lie at the heart of dysfunctional memory development, resulting in symptoms that characterize a multitude of affective disorders (Maren et al, 2013).…”

“…Based on these insights, it thus seems likely that stronger retrieval during context reexposure predicts larger increases in contextual dependency. This may especially be true for emotional memories that typically depend less on context than neutral memories (Cox, Meeter, et al, 2022;van Ast et al, 2013van Ast et al, , 2014. Stronger retrieval during exposure to a similar context may also amplify memory integration, but in this case of the original learning event with a different context (Josselyn & Frankland, 2018).…”

Time-dependent emotional memory transformation: Divergent pathways of item memory and contextual dependency.

“…The Statistical Package for the Social Sciences (SPSS) Version 25.0 (IBM Corp., Armonk, NY) was used to preprocess and analyze the data. The data and analysis code have been deposited at Open Science Framework (OSF) and are available at https://osf.io/ emxgv/ (Cox, 2021). The preprocessing and analyses strategies for the valence and arousal ratings, as well as the cued recall data (baseline and assessment of time-dependent effects), are also on https://osf.io/emxgv/ (described in supplementary materials).…”