People sometimes falsely deny having experienced an event. In the current experiments, we examined the effect of false denials on forgetting and false memory formation. In Experiment 1, participants were presented with emotionally-negative and neutral associatively related word lists known to engender false memories. After encoding, half of the participants had to falsely deny having seen the words while the other half had to tell the truth. During a final memory test (recall or source monitoring task), participants who falsely denied forgot that they discussed certain words with an experimenter. Furthermore, the act of falsely denying reduced the formation of false memories. These results were partially replicated in Experiment 2 where participants also had to re-learn several words and received a second memory task. This latter design feature diminished the effect of false denials on false memory creation. Our experiments suggest that false denials not only have negative consequences (forgetting), but can have positive ones too (reduction in false memories).

False denial is a deceptive strategy that requires fewer cognitive resources than other strategies (e.g. simulating amnesia, fabrication). In the present experiment, we examined the effects of different types of false denials varying in cognitive load on memory. Participants (N = 159) watched a video (theft) and then answered some questions about it. Some participants had to tell the truth about the theft, while others were either asked to falsely deny all the event-related details (i.e. simple false denial) or to falsely deny just some details of the same event (i.e. complex false denial). After two days, all participants completed a memory task in which they truthfully recognized whether details were (i) discussed during the interview or (ii) seen in the video. Additionally, recall scores (i.e. correct details, omissions, commissions) of the memory for the event were assessed. Participants who falsely denied all details reported a higher memory impairment for the interview than the other groups. Interestingly, liars who were engaged in complex denying had the largest memory impairment for the event and reported more commissions than those in the simple false denial group. This experiment shows that under certain conditions, memory is increasingly impaired for high cognitive load lies.

Previous studies showed that feigning amnesia for a crime impairs actual memory for the target event. Lack of rehearsal has been proposed as an explanation for this memory-undermining effect of feigning. The aim of the present study was to replicate and extend previous research adopting a mock crime video instead of a narrative story. We showed participants a video of a violent crime. Next, they were requested to imagine that they had committed this offense and to either feign amnesia or confess the crime. A third condition was included: Participants in the delayed test-only control condition did not receive any instruction. On subsequent recall tests, participants in all three conditions were instructed to report as much information as possible about the offense. On the free recall test, feigning amnesia impaired memory for the video clip, but participants who were asked to feign crime-related amnesia outperformed controls. However, no differences between simulators and confessors were found on both correct cued recollection or on distortion and commission rates. We also explored whether inner speech might modulate memory for the crime. Inner speech traits were not found to be related to the simulating amnesia effect. Theoretical and practical implications of our results are discussed.