Intrusive Thoughts Mediate the Links Between Affective Valence and Prospective Memory

Prospective memory (PM), the ability to remember to carry out intended actions, is influenced by cognitive and emotional factors. This study investigated the effects of affective state changes on PM by experimentally manipulating mood in young and older adults in a within-subject design (negative, neutral, and positive conditions), measuring valence at baseline (T1), post-induction (T2), and post-task (T3). We derived two valence change scores, indexing mood induction-related change (T2-T1) and task-related change (T3-T2), focusing also on the role of intrusive thoughts. PM performance improved when affect was more positive and declined when affect was more negative. Perceived control over intrusive thoughts significantly predicted PM and mediated the effect of post-induction affect change on PM, but not post-task affect change. These relations did not vary by age group. These findings are consistent with capacity-based accounts, suggesting that negative affective states increase distraction via intrusive, task-unrelated thoughts, resulting in PM impairments. Conversely, associations between positive affect and PM may be driven by performance-related affective processes. By isolating when affect matters and how (via intrusive thoughts), the study advances a mechanistic account of affect–PM coupling. Future studies should disentangle the bidirectional affect-performance influence and investigate the cognitive processes underlying intrusive thoughts.