Suppression-induced forgetting: A pre-registered replication of the Think/No-Think paradigm. Stage 2 report in review for the journal Memory.

Abstract

Post-traumatic stress disorder is characterised by recurring memories of a traumatic experience despite deliberate attempts to forget. The Think/No-Think (TNT) task has been used widely in the laboratory to study suppression-induced forgetting. Recent meta-analyses have reported small-to-moderate effect sizes in this paradigm. The current replication was a collaborative effort to evaluate this paradigm following pre-registration. In particular, we conducted an online experimenter-present version inclusive of both the same- and independent-probe tests using a direct suppression instruction, resulting in 150 English-speaking healthy individuals (75 Western and 75 non-Western; 89 females; MAge= 31.14, SDAge = 7.73). The think condition facilitated accurate recall relative to the baseline condition (i.e., the positive control that speaks to the integrity of the procedure). Yet, participants did not show reduced correct recall in the no-think compared to the baseline condition. Thus, we did not replicate the suppression-induced forgetting effect (same-probe test: BF01 = 7.84; d = 0.03 [95% CI: -0.13; 0.20]; independent-probe test: 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 the suppression-induced forgetting effect.