Tracking changes for a positive public event memory: a longitudinal study of the 2024 solar eclipse

Autobiographical memories encompass both personally experienced events and shared public events, each thought to serve distinct functions in daily life. A memory for a given event is known to change over time, with specific details fading while the overall gist is relatively preserved. Whether this pattern differs for personal versus public events remains unclear, particularly for positive public experiences. To address this knowledge gap, we conducted a longitudinal behavioural study in which 175 university students were asked to report on memories for a personal event and a positive public event, the 2024 solar eclipse, four times over six months. At each timepoint, the participants provided free recalls of the memories, answered specific questions about details of the memories, and completed subjective ratings. Using natural language processing to assess gist memory in free recalls, we found stronger preservation of gist for the solar eclipse than for personal memories. Assessing the consistency of specific event details within the memories across time, we found a steeper decline in consistency for the solar eclipse than for personal memories. Finally, the subjective rating responses revealed that the solar eclipse memories retained a stronger confidence in recall compared to personal event memories. These results point towards different trajectories for personal versus public event memories, which could reflect different roles of these memories in daily life.