Recent research published in applied cognitive psychology Evidence shows that the types of false memories people form depend on how believable they are about the event and how often they are told that it happened. The findings suggest that plausible events are much more likely to generate false beliefs, but only if people are led to believe that the event happened only once. These insights help illuminate how suggestion can distort human memory in everyday and legal situations.
To understand the new research, it’s helpful to distinguish between false beliefs and false memories. A false belief occurs when you are convinced that a certain event happened to you, even if you cannot visualize it. False memories go a step further and include vivid sensory details of events that never actually happened, making them feel like real memories.
Memory is generally reliable, but it’s not perfect. It is reconstructive, which means it is malleable and prone to error. When people are exposed to suggestive questions or misleading information, they may adopt false beliefs or false memories.
The new study was authored by Mara Georgiana Moldoveanu from Maastricht University, Babes Bolyai University and the University of Leuven. Ahmad Shavaroui from the University of Leuven. Ivan Mangiuri from the University of Leuven and Aldo Moro from the University of Bari. Javad Khatami of Tehran University. Henry Otger of Maastricht University and Leuven University;
The researchers sought to address a specific gap in memory research regarding event frequency. Previous research suggests that telling someone that an event happened repeatedly is no more likely to form a false memory than telling someone that it happened only once. However, previous research has not examined how this suggested frequency interacts with the plausibility of the event itself.
Understanding this interaction has practical importance for legal and therapeutic environments. In real life, witnesses and victims may be interviewed suggestively about highly implausible situations, such as repeated past abuse or ritualistic events. To better understand these real-world scenarios, the researchers wanted to see if false memories for repeated or unlikely events could be reliably generated in a laboratory setting.
“Suggestion-based false beliefs and memories are not just curiosities in the laboratory. Real-world cases of wrongful conviction and wrongful conviction may involve suggestive therapy and interviews in which not only single abuse but also repeated abuse may be suggested,” the researchers told PsyPost.
“So far, we are still investigating whether it is possible to reliably elicit false memories for repeated events in the laboratory. Abuse reports may also include less believable events, such as satanic rituals. Such real-life cases ultimately represent the real-life inspiration for this study and series of studies, which are intended to be not only interesting but actually relevant.”
To investigate this, the researchers used a technique known as the blind transplantation paradigm. In one typical memory paradigm, scientists often had to contact participants’ parents to confirm childhood events. Blind implantation methods avoid this by relying entirely on the individual’s own initial answers to establish a baseline for what is true or false.
Initially, 855 participants from Western Europe, Romania, and Iran completed an online survey. In this first study, participants read a list of 20 childhood events and answered whether they had experienced them. Two of these items were critical events designed for the experiment.
One, a plausible event, involved losing a toy as a child. Another is a plausible incident where he almost drowned at sea. Scientists filtered the group to find people who said they had never experienced the two significant events.
One week later, 103 of these eligible participants completed a follow-up survey. This final sample had an average age of 33.7 years and was found to be 62.1 percent female. In the second stage, the researchers presented each participant with an individual list of five events.
Four were real events that the participants had actually experienced, and one was a fake critical event that they had previously denied experiencing. Participants were randomly assigned to a group in which the fake event was highly plausible or a group in which it was not.
Additionally, the researchers changed the recommended frequency of false events. They told some participants that the event only happened once, while others said it happened repeatedly during their childhood.
The final breakdown included 25 people in the high plausibility single group, 26 people in the high plausibility repeat group, 30 people in the low plausibility single group, and 22 people in the low plausibility repeat group. The scientists asked participants to rate their belief that the event had happened and their actual memory of the event on an eight-point scale.
The researchers then asked participants to vividly imagine the event. Participants were asked to visualize details such as where it happened and who was there, and write down their thoughts. After this imagination exercise, participants re-evaluated their beliefs and memories.
The data revealed a clear interaction between event plausibility and suggested frequency of false beliefs. When scientists suggested that the event happened only once, high-plausibility events generated much higher false belief ratings than low-plausibility events. Up to 52 percent of people in the plausible single-event group held false beliefs.
In contrast, in the low-belief, one-time occurrence group, only 10 percent formed false beliefs. This suggests that plausibility plays a large role in belief formation when an event is presented as a discrete event. This difference disappeared when the researchers suggested that the event occurred repeatedly.
If the situation was repeated, the plausibility of the event had no statistically significant effect on how strongly people believed it happened. The rate of false beliefs was 38.5 percent in the plausible repetition group and 22.7 percent in the less plausible repetition group. The lowest rate of false beliefs, at 9.1 percent, occurred before in-group imaginative action, considering plausible events that seemed to occur repeatedly.
Researchers believe this interaction may be related to script theory, which concerns a person’s general knowledge of how typical events unfold. When an event is described as occurring repeatedly, existing knowledge about everyday events is activated and can make it seem familiar, regardless of its actual plausibility. On the other hand, if you lack a vivid memory of an event that is likely to repeat itself, you may reject the proposal outright.
Focusing on false memories that require actual sensory recall, the overall rate was lower than the rate of false beliefs. Before imagination, there were no significant differences in false memory ratings based on event plausibility or suggested frequency. False memory rates ranged between 9.1 percent and 16 percent across the various experimental groups.
After asking participants to imagine the event, an interaction emerged, but plausibility or frequency alone did not show strong independent effects on the formation of detailed false memories. These findings provide evidence that false beliefs are more likely to be instilled when an event appears likely to occur and is framed as a discrete event.
The results “highlight that memory is not a recording video camera. Although memory is generally reliable, it is malleable and prone to errors such as false beliefs (certainty that an event happened) and memories (vivid details that feel like reality),” the researchers said. “While these can have practical implications in everyday life, they are even more important in a legal context.”
“That doesn’t mean we should believe our memories or recollections. It just means that we need to consider factors such as context (e.g., suggestive questions) and the plausibility of events and frequency with which they are suggested, especially when assessing our memories in court.”
“This study is a single investigation into the (interactive) effects of plausibility and suggested frequency on false beliefs and false memories,” the researchers added. “Are the effects obtained large enough to have a clear on-the-scene impact? In false memory research, even a single change in a detail of testimony, such as believing the suspect was in a red car, can have practical consequences, such as starting a criminal investigation.”
“While we did find relevant effects (e.g., plausibility), this only meets one criterion for use in the field, such as expert witness reporting. Generalizability (across eras and paradigms) and reproducibility (direct replication) are still needed to achieve reliability. Therefore, this study advances the field, but cumulative evidence is needed.”
As with any research, this study has some limitations that should be considered. The final sample size of 103 people was smaller than the researchers had originally planned, so the study may not have had enough statistical power to detect small effects. It is also possible that some participants had actually experienced a significant event but forgot about it during the initial study. This means that they reported a truly recovered memory rather than a newly implanted false memory.
Future studies should replicate these findings in larger groups to make them broadly applicable to different populations. Scientists also plan to use events for which the absolute truth is known to better separate false memories from forgotten true ones. Identifying the boundary conditions for false memory formation remains an ongoing project that requires accumulating evidence before it can be firmly applied in a courtroom setting.
“This series of studies is part of a broader scientific community studying false memories,” the researchers explained. “The main goals are to identify the factors that influence the formation of false beliefs and memories and to develop ways to reduce false beliefs and memories and their potentially harmful consequences.”
“Another important aspect of this research is determining when its results can be confidently applied to real-world situations, such as courtrooms. This particular project is also relevant to research on self-deception, which can represent a form of motivated false belief. Several laboratories and researchers are investigating these timely topics.”
“For more about our and our colleagues’ work, visit our publications page: https://celleuven.wixsite.com/home/publications. You might also want to check out the work of a group of universities doing research on (false) memories and beliefs, including the University of Chicago, Cornell University, University College Dublin, and the University of Amsterdam.”
The study, “The Effects of Plausibility and Frequency of Suggested Events on the Implantation of False Beliefs and Memories,” was authored by Mara Georgiana Moldoveanu, Ahmad Shahvaroughi, Ivan Mangiulli, Javad Hatami, and Henry Otgaar.
