Collective events and individual affect shape autobiographical memory

Event representation at the scale of ordinary experience

Weeks are divided into weekdays and weekends; years into semesters and seasons; lives into stages like childhood, adulthood, and adolescence. How does the structure of experience shape memory? Though much work has examined event representation in human cognition, little work has explored event representation at the scale of ordinary experience. Here, we use shared experiences - in the form of popular television shows - to explore how memories are shaped by event structure at a large scale. We find that memories for events in these shows exhibit several hallmarks of event cognition. Namely, we find that memories are organized with respect to their event structure (boundaries), and that beginnings and endings are better remembered at multiple levels of the event hierarchy simultaneously. These patterns seem to be partially, but not fully, explained by the perceived story-relevance of events. Lastly, using a longitudinal design, we also show how event representations evolve over periods of several months. These results offer an understanding of event cognition at the scale of ordinary human lives.

The day-of-the-week effect is resilient to routine change

Temporal landmarks are salient events that structure the way humans think about time. They may be personal events, such as one's birthday, or shared cultural events, such as the COVID-19 pandemic. Due to societal habits, the cyclical weekly structure - for example, working on weekdays, resting on the weekends - helps individuals orient themselves in time. In the "day-of-the-week effect," individuals are faster at reporting which day of the week it is on weekends than they are on weekdays. Herein, we hypothesized that the disruption of social habits during the COVID-19 pandemic lockdowns may have weakened this effect, thereby accounting for the "Blursday" phenomenon. In the current study, speeded responses to the question "What day of the week is it?" were collected online from 1,742 French participants, during and after the lockdown periods. We found that reaction times for days of the weekends remained faster than for weekdays during the lockdown, although the overall reaction times were significantly slower during lockdown. We also found that responses were slower as governmental stringency rules and restrictions in mobility increased. Our results suggest that the weekend landmark remains a stable temporal anchor in French culture despite the experienced temporal distortions induced by the disruption of social habits during the pandemic. We conclude that cultural temporal landmarks shape socially shared temporal cognitive maps.

Overestimating the intensity of negative feelings in autobiographical memory: evidence from the 9/11 attack and COVID-19 pandemic

When recalling autobiographical events, people not only retrieve event details but also the feelings they experienced. The current study examined whether people are able to consistently recall the intensity of past feelings associated with two consequential and negatively valenced events, i.e. the 9/11 attack (N = 769) and the COVID-19 pandemic (N = 726). By comparing experienced and recalled intensities of negative feelings, we discovered that people systematically recall a higher intensity of negative feelings than initially reported - overestimating the intensity of past negative emotional experiences. The COVID-19 dataset also revealed that individuals who experienced greater improvement in emotional well-being displayed smaller biases in recalling their feelings. Across both datasets, the intensity of remembered feelings was correlated with initial feelings and current feelings, but the impact of the current feelings was stronger in the COVID-19 dataset than in the 9/11 dataset. Our results demonstrate that when recalling negative autobiographical events, people tend to overestimate the intensity of prior negative emotional experiences with their degree of bias influenced by current feelings and well-being.

Understanding the structure of autobiographical memories: A study of trauma memories from the 1994 Rwandan genocide

How do we remember traumatic events, and are these memories different in individuals who experience post-traumatic stress? Some evidence suggests that traumatic events are mnemonically enhanced, or include more episodic detail, relative to other types of memories. Simultaneously, individuals with post-traumatic stress disorder (PTSD) have more non-episodic details in all of their memories, a pattern hypothesized to result from impairment in executive function. Here, we explore these questions in a unique population that experienced severely traumatic events more than 20 years ago - individuals who lived through the 1994 genocide in Rwanda. Participants recalled events from the genocide, negative events unrelated to the genocide, neutral events, and positive events. We used the Autobiographical Interview method to label memory details as episodic or non-episodic. We found that memories from the genocide showed robust mnemonic enhancement, with more episodic than non-episodic details, and contained more details overall than any other memory type. This pattern was not impacted by post-traumatic stress. Overall, this study provides evidence that traumatic events create vivid long-lasting episodic memories, in this case even more than 20 years later.

The COVID-19 pandemic as autobiographical period: evidence from an event dating study

The COVID-19 Pandemic is undoubtedly one of the most impactful and ubiquitous public events in recent history. In this study, we focused on how it affected the organisation of autobiographical memory by examining how often individuals referred to the COVID-19 Pandemic while estimating the date of their autobiographical memories. To that end, we collected word-cued memories from the recent past, event dating protocols, COVID-relatedness ratings, and the transitional impact scores from first-year undergraduates. We found that participants frequently recalled COVID-related memories, and often used the Pandemic as a temporal landmark for dating both COVID-related and unrelated memories. Importantly, reference to the Pandemic in dating estimates was as frequent as the references to other important life periods (high school, university). Despite affecting the lives of these individuals only moderately in psychological and material terms, these data indicate that the Pandemic has become a prominent landmark in autobiographical memory, shaping the way we remember and situate past experiences.

Multiple routes to enhanced memory for emotionally relevant events

Events associated with aversive or rewarding outcomes are prioritized in memory. This memory boost is commonly attributed to the elicited affective response, closely linked to noradrenergic and dopaminergic modulation of hippocampal plasticity. Herein we review and compare this 'affect' mechanism to an additional, recently discovered, 'prediction' mechanism whereby memories are strengthened by the extent to which outcomes deviate from expectations, that is, by prediction errors (PEs). The mnemonic impact of PEs is separate from the affective outcome itself and has a distinct neural signature. While both routes enhance memory, these mechanisms are linked to different - and sometimes opposing - predictions for memory integration. We discuss new findings that highlight mechanisms by which emotional events strengthen, integrate, and segment memory.