There are some memories you wish you could forget. I wish I could forget the time in high school when, during the finals of a debate tournament, I accidentally spent an entire speech in front of an auditorium packed with people making arguments in favor of the opposing team’s side. While the loss of this debate competition was quite embarrassing, there are other, much more serious memories that may be beneficial for people to forget. For instance, a clinician might have a patient working to overcome a debilitating fear of dogs who may benefit from treatments that extinguish their fear-related memories. The idea of erasing memories may seem like fiction—the premise of a movie like Eternal Sunshine of the Spotless Mind or TV show like Black Mirror. But researchers have given serious focus to examining ways of inducing forgetting.

One approach that scientists have recently examined is “reminder-dependent amnesia.” Essentially, people are shown a cue to get them to retrieve a memory and then receive a manipulation, like a shock or drugs (e.g., midazolam). Ideally, this manipulation results in the just-remembered memory being less likely to be expressed later. Given its potential to help patients with PTSD, anxieties, and phobias, this basic phenomenon has recently sparked considerable interest among clinicians. However, the evidence about the efficacy of reminder-dependent amnesia for treating psychopathology has been mixed and contradictory findings have gone unexplained. In other words, in practice, there’s been little success in applying it to mental health patients.

In a recent Psychonomic Bulletin & Review paper, researchers Natalie Schroyens, Tom Beckers, and Laura Luyten (pictured below) identify foundational issues with reminder-dependent amnesia that should be addressed before this research can be practically applied in clinical settings.

Their key argument is that current research on reminder-dependent amnesia has focused too heavily on one underlying psychological mechanism: reconsolidation. The diagram below shows how it works. When people retrieve a memory, it becomes more malleable and can be modified by clinical treatments. This modified memory can then “reconsolidate,” or turn into a more stable state over time. By this explanation, reminder-dependent amnesia occurs because the memory itself is changed by the manipulation accompanying the reminder. This modified memory is weaker and less likely to affect peoples’ behavior later. It sounds like a perfectly reasonable explanation for data from experiments on the topic.

But this isn’t the only possible explanation. It’s entirely possible that when people retrieve a memory, they also form a new memory, instead of modifying the original one. This newly formed memory could compete with the old one, making the original memory less likely to be expressed at a later time. This alternate explanation would just as easily explain the data from a typical experiment on reminder-dependent amnesia, but it would suggest a different underlying mechanism—with different constraints and clinical implications.

Researchers studying reminder-dependent amnesia typically don’t search for alternate mechanisms, and instead tend to infer that when reminder-dependent amnesia is observed, it is due to reconsolidation. As the authors of the featured paper noted, this inference is problematic for a few reasons:

• Faulty conclusions: Researchers may make an inference about one psychological mechanism – reconsolidation – based on data from an experiment in which another mechanism was really occurring because they didn’t explicitly check for this.
• Discouraging research: Since one theory dominates the field, researchers may be less inclined to examine other possible explanations.
• Explaining away: When an experiment fails to show evidence of reconsolidation, researchers can make post-hoc rationalizations or add extra, conflicting assumptions to make sense of the data in light of the existing theories—rather than refining the theories.

These different factors may have all contributed to the difficulty clinical researchers have faced in implementing reminder-dependent amnesia to treat psychopathology.

So, where should future research on this topic go? The authors suggest a number of directions that might help improve the state of the field, including building more precise, falsifiable theories that may help avoid any one perspective from gaining undue influence in the field. Additionally, they recommended taking various measures to improve the reliability and generalizability of empirical findings. The last recommendation is that researchers should be more careful before presuming that an empirical observation necessarily implies a specific, unobservable underlying mechanism.

This final point is perhaps the most critical, as it is a lesson all researchers in cognitive science may benefit from. In the words of the authors:

“In general – and this is by no means unique to the reconsolidation field, but is basically true for any science built on observation – we should be cautious when inferring the involvement of an unobservable process from an observed effect.”

Overall, the authors of the featured paper note that there is plenty of evidence of reminder-dependent amnesia. But to translate this research into clinical settings, there needs to be more clarity about what mechanisms explain the effect and what conditions make the effects less likely. So, can reminder-dependent amnesia help clinicians’ patients reliably erase unwanted memories about their fears and anxieties? Not yet, but perhaps in the future, with more time and research.

Featured Psychonomic Society Article

Schroyens, N., Beckers, T. & Luyten, L. (2022). Appraising reconsolidation theory and its empirical validation. Psychonomic Bulletin & Review, https://doi.org/10.3758/s13423-022-02173-2