Denial-Induced Forgetting: False Denials Undermine Memory, But External Denials Undermine Belief

We examined the mnemonic effects of false denials. In a previous experiment (Otgaar, Howe, Memon, & Wang, 2014), false denials resulted in participants denying that they talked about details with the experimenter when in fact they did. This denial-induced forgetting (DIF) was further examined. In Experiment 1, participants received pictures and their belief and memory for details were tested. In the false denial group, participants had to falsely deny in response to each question. In the external denial group, an experimenter falsely denied to the participants that certain details were present. The control group had to answer the questions honestly. We found evidence for DIF. In Experiment 2, we used a video and again found DIF. Moreover, when the experimenter provided external denials, nonbelieved memory rates increased. Together, our experiments suggest that false denials undermine memory while external denials appear to reduce belief.