Modification of episodic memory valence through retrieval-update mechanisms requires a narrative link between events

Abstract

Many mental health problems stem from negative life experiences. Memories of such experiences are not only distressing in and of themselves, but may also contaminate existing autobiographical memory networks. To date, little is known about the modifiability of previously formed episodic memories, particularly their affective valence. To investigate this, we developed the Modification Of Valence In Episodes (MOVIE) paradigm, modelling rich episodic memories with high experimental control. First, we established that film clips can change the valence of neutral pictures (Experiment 1). In a series of preregistered experiments, we then assessed whether the valence of neutral (Experiment 2) and emotional (Experiment 3-4) memories can be modified when retrieval is followed by a new emotional experience, and if so, if this experience needs to be related to the memory (Experiment 4). Across experiments, participants first encoded memories of film scenes, representing lifelike experiences. The next day, they retrieved each episode and rated their feelings, before viewing a valence-incongruent scene from the same film. A day later, participants again retrieved and rated day-1 memories. Collectively, results indicated that the valence of previously formed episodic memories can change when memory retrieval is followed by a new emotional experience compared to when memories are merely retrieved. Importantly, updating was only observed when episodes were from the same film, highlighting the importance of narratives in memory binding. Insights into how memories transform with new experiences is critical for understanding why adverse experience sometimes lead to pervasive problems, and may simultaneously be harnessed for treatment innovation.