In Apple TV+’s new series Severance, Adam Scott plays Mark, an employee of Lumon Industries that has a unique approach to work-life balance. When you’re at work, the company blocks all memories of your home life and vice versa. That way you’re never distracted by any intrusive thoughts and can devote your full energy to each phase of your life. Of course, things go wildly wrong, with employees’ personalities splintering into “Innies” and “Outies” with very different priorities.
It’s a cool and creepy premise, but it got us thinking: How close is modern science to being able to selectively edit our memories? We delve deep into the latest research to see whether it’s possible.
In the Wires
The actual process of how memories are formed and stored in the brain is a topic of much discussion. The general consensus is that the frontal cortex and the hippocampus encode your sensory input into “experience,” which is then encoded into specific groups of neurons in the brain. These memories take multiple forms—sensory memories, the ability to recall impressions from your sense organs; short-term memories, which are used for brief spans of time and typically have low emotional content; and long-term memories, which can be further split into implicit and explicit memories. It’s the latter that scientists are working on.
Not being able to physically pinpoint the location of a memory makes it difficult to intervene in their operations. But what’s fascinating is how our brains operate in an almost quantum-mechanical manner when we bring those memories back to the surface. The technical term is “reconsolidation,” where the act of recovering and revisiting a past experience alters the memory itself. This is a pretty big shift in how we understand the process to work, and it’s still being explored. But it opens the door to multiple methods of altering and removing memories after they’re created.
Plugging In
The most successful memory experiments that have been performed to date revolve around implantation—making people believe something happened that didn’t. It’s a lot easier to put something in than take something out. Think Inception, but without the effects budget.
One of the most notable names in the field is Elizabeth Loftus, a cognitive psychologist who has been conducting experiments around false memories for decades. In the 1970s, she began exploring “misinformation effect,” the theory of determining how the presentation of an event shapes how memories of it are created. She spun that out into the notorious “Lost in the Mall” experiment, where she implanted a false recollection of being abandoned in a shopping center and found by parents into over 25% of the study’s subjects.
Her process involved using close friends or relatives of the subjects and having them share the false story along with several real anecdotes from their past. The contextual framing, along with the information coming from trusted confidantes, was enough for a significant portion of the subjects to not only identify the false memory as a real one, but also consider it more believable than events that actually happened to them.
There is some criticism of the methodology used in the study, but it’s illustrative that memories are fluid and can be manipulated through decisively low-tech means.
Cutting Out
Removing a memory is a different story entirely. Because of the complex biological mechanisms in the brain, it’s difficult to pinpoint specific individual memories. But research has proven that types of memories can be targeted by a variety of means. A 2009 study focused specifically on neurons in the lateral amygdala that were activated by the processing of fear memories. Dissection of the tissue found that these neurons were uniformly higher in cyclic adenosine monophosphate response element-binding protein (CREB).
The next step was to take a group of mice, create a fear memory in them using auditory cues and negative stimuli, and then scan their brains to find the CERB-expressing neurons. Finally, using an engineered diphtheria toxin, the researchers were able to destroy those neurons. The result? The audio cue that previously provoked a fear response no longer did. Memory erased.
Of course, a mouse’s brain is orders of magnitude simpler than a human’s, and there’s no real way of knowing what collateral damage was done as a result of the procedure. This is just the first small step that illustrates that the central idea of memory removal is possible on a biochemical basis. Further experiments will work with more precise and targeted technologies, including lasers that can ionize neurons on the individual level.
Splitting the Difference
Finally, let’s tackle the technological conundrum posted by Severance, in which a person has selective access to their memories depending on their location. While this may seem impossible, there is actually precedent in the world of psychology. Dissociative identity disorder (DID), previously known as multiple personality disorder, is an uncommon condition in which individuals perceive themselves as distinct persons inhabiting a single body. Memory loss is a common associated symptom, with patients often lacking conscious recall of actions taken by other personalities.
This “interpersonality amnesia” commonly affects explicit long-term memories—your conscious recollection of events, conversations, and emotions around a specific moment. Studies of DID patients show that they are often unable to access these when a personality that did not form them was in control. Experiments on subjects with this disorder have been inconclusive, but in general, it was found that implicit memories—skills and unconscious connections—were more likely to be transferred between personalities. While the biochemical causes of DID are still unknown, it provides an entry point into “gating” the memory process.
In 2014, scientists at MIT performed the most advanced experiment to date with this process. They marked neurons in the brains of mice with a light-sensitive protein and used fiberoptic cables to send pulses of protons through and activate or deactivate them. This was used to trigger positive or negative memories and determine how they affected the mice’s response to their current situations.
In the case of negative memories, which were created by giving the mice mild electrical shocks from a panel on the floor, the scientists were able to lessen the fear response from the panel after “replaying” that memory in a positive situation—where the mouse was surrounded by females. The opposite was also true—positive memories could be diminished by replaying them in negative situations.
So while it doesn’t look like your job will be able to make you forget it when you clock out quite yet, the field of memory study is making steady progress on being able to manipulate your recollections. Whether that’s a positive or a negative is still up in the air, but are there really bad side effects if you can’t remember them?
