The best sci-fi thriller on HBO Max reveals a controversial scientific debate

What do our memories mean to us? Everything.

Memory defines who we are and connects us to the people we love, even when they’re no longer in our lives.

But as time marches on, our memories naturally fade into the recesses of our minds. And once we lose our memories, their absence tends to haunt us.

“Truth is, nothing is more addictive than the past,” Nick Bannister (Hugh Jackman) tells his trusted assistant, Watts (Thandiwe Newton), in Reminiscence, Warner Bros.’ latest sci-fi blockbuster (now in theaters and on HBO Max).

Nick’s clients come into his place of business seeking “reminiscence,” or the ability to re-experience crucial memories that have become faded or lost. To deliver this immersive experience, Nick submerges clients in a pod-like bath, letting them access memories through a combination of guided hypnosis, electrodes, and drugs that “relax the neural pathways,” as he puts it.

“We all have the experience that our memories for events from our lives — so-called ‘episodic memories,’ which refers to episodes that happened at a particular time and place — seem to get foggier with each passing year,” Jesse Rissman, an associate professor of psychology at the University of California, Los Angeles, tells Inverse.

For his part, Nick is more caught up in his memories of lost love than whatever his clients seek to recall, setting up the audience for a thrilling ride as Nick uses “reminiscence” to figure out what happened to the sweetheart who ghosted him.

But as it turns out, Nick’s “reminiscence” business isn’t just pseudoscience conjured up by writer-director Lisa Joy — at least, not entirely.

Real cognitive and behavioral science is rooted in the film’s central concept, and it’s comparable to actual techniques psychologists and neuroscientists use to help patients retrieve memories. However, the science at the core of real-life “reminiscence” is hotly debated and controversial.

How does the human brain store and retrieve memories?

Three components of the brain deal with storing general information and episodic memories. These are:

• Hippocampus
• Neocortex
• Amygdala

Out of these sections, the first plays a particularly essential role in storing episodic memories “The hippocampus is thought to be critical for storing the blueprints — for keeping a record of how different parts of the brain were interconnected as an event was experienced,” explains Elizabeth Kensinger, a professor of psychology at Boston College who has extensively studied memory retrieval.

“We can then think of memory storage as creating a set of blueprints that allow you to ‘rebuild’ that event when you later retrieve it,” Kensinger tells Inverse.

But the hippocampus doesn’t operate alone. The content of our memories is “stored in other portions of the brain and must be reconnected at the moment of retrieval for us to be able to recollect an event,” she adds.

“Memory doesn't just live somewhere permanently in the brain, waiting to be pulled out from storage.”

In Reminiscence, Nick helps clients retrieve long-lost memories. But the process of recovering memories from this part of our brain isn’t as simple as Reminiscence would have you believe. “It's important to recognize that a memory doesn't just live somewhere permanently in the brain, waiting to be pulled out from storage,” says Kensinger. “Retrieval is an active process.”

Rissman adds, rather than bringing back precise visual details of our memories, the scientific process of memory retrieval “involves our best attempt to reconstruct a plausible account of what happened at a specific time and place — given the fragments that we’re able to recall.”

Can we recall memories long after we’ve forgotten them?

Yes, say the experts. But you don’t need to be a neuroscientist to understand this concept. We’ve all experienced the sensation of suddenly recalling a long-lost memory.

Perhaps you walk through a park, and the sight of roses reminds you of when you planted flowers in a garden bed as a child. Maybe you step into an elevator, and the scent of a fellow rider’s perfume reminds you of an ex-lover’s signature scent.

We often associate memories with specific cues related to our five senses — touch, sight, hearing, smell, and taste — which can help us recall these memories later on. “Sensory cues often seem to allow us to bypass more complicated search processes,” says Kensinger.

But instead of using such cues, Reminiscence sees Nick deliver verbal prompts to bring clients back into their memories, a process not unlike hypnosis.

Using guided hypnosis as a strategy to recall memories became popular during the ‘80s and ‘90s, as psychologists began to support the view that individuals who’ve experienced traumatic events can repress memories. One argument for hypnosis is that such techniques can help victims of child abuse and those experiencing post-traumatic stress disorder (PTSD) to recover repressed memories years later.

“Proponents of this view adduced studies to support the claim that many survivors encode trauma memories yet become incapable of recalling them, except under special circumstances such as hypnosis,” wrote the authors of one 2019 study. Yet, other psychologists dispute theories of memory repression, and some argue that techniques associated with it can generate false memories instead of retrieving real ones.

In 1995, UC Irvine professor Elizabeth Loftus and now-University of Washington professor Jacqueline Pickrell published a study supporting the concept of “false memories.” Loftus and Pickrell suggested to participants that they’d become lost in a mall when they were five years old. Roughly a quarter of participants believed the false memory and began recalling specific details about the experience, though Loftus and Pickrell had invented the scenario.

“Memory repression would result in a complete loss of access to the memory.”

“Memory ‘repression’ would be something that happens with effort or awareness and that would result in a complete loss of access to the memory,” says Kensinger, adding that “there is not convincing evidence of this phenomenon.”

But “memory suppression,” which Kensinger likens to snuffing out a candle flame, is real. She calls it “an effortful process by which memories become less and less accessible” over time.

“You might think of suppression as making it less likely that you pull up the blueprints for a particular event,” adds Kensinger. “The blueprints still exist... but the event is less likely to spring to mind at undesired times.”

Memory suppression plays a crucial role in Reminiscence; it’s because clients have lost access to their memories — and desperately want them back — that Nick has a business.

Can we use brain science to retrieve memories in the future?

According to Rissman, the reason most people forget memories isn’t necessarily linked to the degradation of brain neurons, as in the case of people experiencing Alzheimer’s disease.

Instead, the emergence of new memories can interfere with retaining older ones. “The similarity between our past event memories creates competition, which our brain needs to resolve when attempting to retrieve a specific memory,” Rissman explains.

And there’s no guarantee that our brains will accurately recall any one distinct memory that bears similarities to another. “Each time we recall a memory, we have the potential to change it,” he adds. This phenomenon is known as “reconsolidation.”

Scientists can use electrical impulses to improve memory recall by stimulating “parts of the brain that support our retrieval strategies, such as the lateral prefrontal cortex,” Rissman further explains. In a 2019 study, Rissman himself used electrical stimulation to “boost people's ability to use cues in their present environment — like a word or a photograph or a sound — to help search their memory and access past associations they were struggling to recall,” he says.

In Reminiscence, Nick places electrodes on his clients, submerging them in a sensory deprivation tank. It’s unclear whether these electrodes deliver electrical stimulation or merely help Nick monitor the client’s brain activity.

But Rissman suggests using electrical stimuli to bring back precise memories will forever be the stuff of science fiction. Simply put, this technique wouldn’t match up with the imprecise ways our brains can retrieve memories.

“It is unrealistic that we would ever be able to create a technology that could stimulate specific parts of the brain and bring back detailed and accurate memories that were seemingly lost,” Rissman argues.

That’s because our memories in real life are more fluid and changeable than those seen in Reminiscence, which finds Nick helping his clients recall the precise details of a forgotten moment, then projecting those memories on a holographic screen.

“Our brain does not maintain a pure record of what happened in each moment of our lives,” adds Rissman. “Memory is not like a video camera.”

Reminiscence is now in theaters and streaming on HBO Max through September 19.