Golden slumber? The elusive role of sleep in emotional memory

Emotional memories shape how we perceive ourselves and the world. While they often serve adaptive functions, they have also been linked to the onset and persistence of affective disorders. Sleep is frequently disturbed in these conditions and has been proposed to play a key role in emotional memory processing. Empirical evidence, however, remains inconclusive, and theoretical accounts diverge: whereas some suggest sleep preserves or amplifies memories’ emotional tone, others propose a downregulating effect of sleep. This dissertation investigated whether, and under what conditions, sleep modulates the emotional impact of memories. Across a series of studies, we combined naturalistic paradigms with behavioural and psychophysiological measures. Using socially distressing tasks, we induced autobiographical experiences and later reminded participants of them after intervals including either sleep or wakefulness. Emotional responses triggered by the previously induced memories were assessed through subjective ratings and physiological measures (e.g., facial blushing). Contrary to our predictions, sleep could not be reliably linked to changes in the emotional tone of memories. The observed alterations in emotional responses were often unrelated to memory and sleep. Instead, findings suggest that factors such as future relevance and sleep quality may moderate emotional memory processes. Together, these results highlight the complexity of the relationship between sleep and emotional memories and challenge the idea of sleep as a simple mechanism for reducing or amplifying memories’ emotional tone. While healthy sleep may support general emotion regulation, it does not consistently reshape emotional memories. This work underscores the need for more nuanced models to capture how emotional experiences are processed over time.