Theo Tobel (TT): Professor Schacter, thank you for taking the time to speak with me today. In your book The Seven Sins of Memory, you determined that errors in memory often reflect the operation of adaptive processes in human evolution. Could you please explain and expand on this idea?

Daniel Schacter (DS): When I first started writing about the seven sins—transience, absent-mindedness, blocking, misattribution, suggestibility, bias, and persistence—and was attempting to organize memory errors, I realized that memory errors can have huge consequences in everyday life. For example, mistaken eyewitness identification, which is due to the sin of “misattribution,” is a major cause of wrongful convictions. So then I wondered, why do we still have such an error-prone memory system? There must be some evolutionary advantage to these memory errors. 

The sin of misattribution—when you correctly remember aspects of an event or experience but misremember the source of the event—illustrates these evolutionary advantages. As in the case of wrongful convictions, a witness may claim that they saw a certain individual committing a crime, when in fact this is a mistaken testimony: the person they recognize was at the crime scene but was not committing the crime. This memory error helps us in most cases because it allows us to remember the gist of the event. Most of the time, the source of the event is not all that important—instead, we internalize the general sense of what happened in the situation. 

The usefulness of memory’s sins can be further exemplified by the very first sin of memory, “transience,” which is a gradual loss of information over time. How does this sin assist us? If we recorded everything that happened and constantly had access to it, that would be potentially impossible to manage—we’d be overwhelmed with trivial details. So transience allows us to selectively retain only the most evolutionarily-important information. This same logic can be applied to the six other sins, and thus I arrived at the conclusion that these sins may in fact be beneficial. 

TT: In the process of selectively encoding and reconstructing memories, are memories with positive and negative valence retained differently?

DS: Generally, we know that emotionally-arousing experiences—either positive or negative—are retained over time more so than neutral experiences. There’s some evidence that supports the hypothesis that negative events can be retained more specifically and with a greater recall of particular details. 

TT: If the negatively charged memories are more specific, would you say the brain has adapted to avoid pain rather than seek pleasure?
 
DS: I’m not sure if I’d go that far, but this definitely relates to the seven sins and specifically the seventh sin, which I call “persistence.” This is the idea that experiences—especially traumatic ones—can persist in the mind in vivid detail. They may become so intrusive that they interfere with psychological functioning, which can result in depression and other debilitating conditions. We must ask again, why is that so? I go back to the adaptive perspective, which holds that remembering negative experiences may allow us to avoid something in the future that could threaten our survival, and yet we have a negative side effect that I call persistence.

TT: The concept of false memories and the formation of memories that are completely fabricated is particularly intriguing to me. How can people distinguish between “deep fakes” and real sources so that they can avoid the formation of these false memories?

DS: There have been many brain imaging studies on this, and most find that true memories activate areas of the visual and auditory cortices more than false memories, but that’s not always the case. People also tend to believe fake news that aligns with their pre-existing beliefs—this is a type of confirmation bias, so it’s important to be aware of the role bias plays in the formation of these memories. I also think that deep fakes are so widely publicized that everyone is aware of this possibility when reading the news. Therefore, we must be careful critics of our sources and use our judgment to determine the validity of information online.

TT: Is it possible to “expel” false information from your memory and rid yourself of those biases?

It's difficult. In the 1990s, Elizabeth Loftus showed this with the “lost in a shopping mall” study. Loftus found that it was possible to implant memories of events that never occurred—that participants had been lost in a shopping mall as a child—merely through suggestion. When most participants were first asked to remember this event, they said, “No, that never happened to me.” However, when participants were repeatedly questioned, more than a quarter of them “remembered” the false event. Even more so, after these participants were debriefed and told that the event in question never occurred, some remained steadfast in their beliefs that this fabricated memory was real (Loftus & Pickrell, 1995).

TT: I think this is especially relevant now, as we have seen increasing rates of fake news and misinformation appearing in news coverage and in our everyday lives. 

Since your 20-year update of The Seven Sins in 2021, there have been drastic technological advancements, such as the public release of large language models like ChatGPT. Do you think that these advancements will have an impact on memory errors? If so, how?

DS: It’s hard to say—ChatGPT hasn’t even been publicly available for a year, yet it is so prevalent in every field. One of my graduate students, Will Orwig, is studying the relationship between memory and creativity, which I have been fascinated with for many years. This connection is based on the principle that our episodic memories (memories of personal experiences) allow us to generate creative ideas because memories themselves are reconstructions of the past. ChatGPT does the same thing: it is an intelligent program that uses diverse and detailed ideas to create new, nuanced ideas. We must ask ourselves if our ideas are more creative than this model’s, and in Will's study of creative writing, we find that ChatGPT writes stories that are just as creative as those written by human participants. I can’t say for certain how these advancements will impact memory errors because there haven’t been enough studies on this question yet.
 
TT: How have scientific advancements affected your work and your research?

DS: The emergence of neuroimaging technologies such as PET scans and fMRI transformed memory research—these tools allowed researchers such as myself to observe brain activity and the specific brain regions that “light up” during certain cognitive processes and memory tasks. At the time, it was almost like something out of your favorite science fiction novel—just unimaginable a decade earlier. 

Scientific advancements have also affected and possibly impaired humans’ memories. There is a ubiquitous concern that technological innovations, such as GPS, may have a negative impact on a person’s overall spatial memory, not just their ability to remember the route to the dentist’s office that the navigation system is now providing them. 

Psychological experiments indicate that a device such as GPS can impair memory of specific routes, something we’d call a task-specific effect. On the bright side, there’s very little evidence that GPS has a general impact on memory impairment—it is difficult to ascertain correlation from causation (i.e. people who use GPS are more likely to have a worse memory in the first place). 

TT: Where do you think there are still gaps in our understanding of memory, and what types of research can be done to address these gaps in knowledge, either for memory or in psychology in general?

DS: Wow, that's a big question. There is still a pretty substantial gap between the “systems” level of neuroscience—which encompasses the study of memory—and the cellular or molecular levels (i.e. looking at neurons and genes). Very recently, there’s been exciting progress in mapping neural connectivity and generating ultra-sharp scans of the entire mouse brain (Johnson et al., 2023). In general, though, there’s still a lot of research and innovation to be done to narrow that gap. 

TT: As a renowned memory researcher, do you have any recommendations for students looking to avoid succumbing to the sin of transience? Is there a special trick for remembering material for midterms or final exams? 

DS: Well, there are a number of them, and they're pretty well documented, but I think probably the best one is retrieval practice or self-testing. In my update of The Seven Sins, I wrote about the testing effect, which shows that active recall not only helps you strengthen your knowledge of the material but specifically helps with retaining information over time. The effort to retrieve information through quizzing yourself and making concept maps and flashcards instead of reading the material over and over again is sure to boost your memory. 

TT: I have a math midterm next week, so I'll be sure to use that technique. That's all the questions I have—I'm really so thankful and so honored to speak to you about memory and its implications and unknowns. Thank you so much for your time.

This interview has been edited for clarity.