Suppression-induced forgetting: a pre-registered replication of the think/no-think paradigm.

Post-traumatic stress disorder is characterised by recurring memories of a traumatic experience despite deliberate attempts to forget (i.e., suppression). The Think/No-Think (TNT) task has been used widely in the laboratory to study suppression-induced forgetting. During the task, participants learn a series of cue-target word pairs. Subsequently, they are presented with a subset of the cue words and are instructed to think (respond items) or not think about the corresponding target (suppression items). Baseline items are not shown during this phase. Successful suppression-induced forgetting is indicated by the reduced recall of suppression compared to baseline items in recall tests using either the same or different cues than originally studied (i.e., same- and independent-probe tests, respectively). The current replication was a pre-registered collaborative effort to evaluate an online experimenter-present version of the paradigm in 150 English-speaking healthy individuals (89 females; MAge = 31.14, SDAge = 7.73). Overall, we did not replicate the suppression-induced forgetting effect (same-probe: BF01 = 7.84; d = 0.03 [95% CI: -0.13; 0.20]; independent-probe: BF01 = 5.71; d = 0.06 [95% CI: -0.12; 0.24]). These null results should be considered in light of our online implementation of the paradigm. Nevertheless, our findings call into question the robustness of suppression-induced forgetting.