Forgetting as a Consequence of Retrieval Suppression: A Meta-Analytic Review

Suppressing retrieval of a memory when faced with a reminder has been shown to reduce the probability of that memory coming to mind in the future, a phenomenon known as Suppression-Induced Forgetting (SIF). However, efforts to observe SIF have sometimes failed, leading some to question the robustness of the effect. To address this issue, we conducted a comprehensive meta-analysis of SIF within the Think/No-Think paradigm including several key methodological variants to the original design. Across 500 effects from 120 studies, we observed a consistent aggregate SIF effect (d ≈ 0.20 – 0.40) measured using either same probe (SIF ≈ 6%), independent probe (SIF ≈ 5-6%) or recognition (SIF ≈ 2-4%) tests. Notably, there was considerable methodological variability, and prediction intervals revealed substantial heterogeneity. Moderator analyses undertaken to explain this variability found SIF to be credibly larger when using (a) relatively more repetitions during the Think/No-Think phase within same probe data; (b) thought substitution instructions within same probe data (with the opposite observed for independent probe data); and, (c) autobiographical memories (or future worries) as opposed to words or images. Results provide compelling evidence of the SIF effect but also suggest areas for future expansion.