Have you ever thought that your memories are unchanging, permanent records of past events? Like facts that you can refer to when the moment strikes you? Or do they seem to change over time? A new study published in Neuroscience & Biobehavioral Reviews finds that each time we remember something, our brains actually reconstruct the memory. This is because we blend details from the original event with our current situation. In fact, this is why it seems that memories can shift, fade, and become less accurate over time.
Memories Aren’t Stored Like Files
The study comes from researchers at the University of Texas at Dallas and the University of East Anglia. It reviewed almost 200 journals across neuroscience, psychology, philosophy, and animal research to create a framework for episodic memory. This is a type of long-term memory that enables recall of past experiences in the context of place, time, emotions, and more.
Researchers aimed to define what qualifies as a memory, explore how the brain stores memory, and explain why remembers seems to alter it.
What they found is that memories aren’t stored like files. They’re not a mental archive that you can pull up when you need. Memories actually consist of several components. Some are easy to access, but others remain inactive until a cue triggers them – like a place, smell, or question.
To be an actual memory, researchers say it must be linked to a real event in the past. But even then, what we remember isn’t often an exact copy of the original experience.
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Why Memories Aren’t Always Reliable
Professor Louis Renoult, lead researcher at UEA’s School of Psychology, says memories can “include extra details from our general knowledge, past experiences, or even the situation we’re in when we remember it.”
The study explored a process called re-encoding or memory reconsolidation, in which older memories become updated each time they’re recalled. Researchers suggest that this process of updating is ongoing. This is why memories can become distorted, sometimes less clear, or confusing over time.
“This work helps us understand why our memories aren’t always reliable and how they can be influenced by time, context, and even our own imaginations,” Renoult said.
To explore how the brain processes memories, researchers examined the hippocampus–the part of the brain responsible for forming and organizing memories. What they found is that memory traces can remain unconscious and inactive until a cue in your environment activates them.
However, what our brains recall is a conscious representation of the experience combined with generic knowledge of the world around us, our current emotions, and any new information or context that may be relevant to the current situation.
The brain’s way of combining this information explains why episodic memory is a useful tool and also highly fragile. Because the brain stores memories in flexible ways, episodic memory becomes vulnerable to change over time.
The “Broken Telephone” Game Illustrates This Well
If you ever played the “Broken Telephone Game” as a kid, you probably already understand that a story changes with each retelling, becoming less accurate the more the memory is accessed. At the end of the game, the original phrase is not usually even close to where it began.
But why does this happen? That’s what researchers aimed to find out.
The research team looked at nearly 200 studies, ranging from human brain imaging and neuropsychological cases to philosophical analysis and animal models. Exploring the range of studies allowed researchers to better define memory representations and dive into the ways our brains change them.
Renault said, “The goal was to make sense of problems that haven’t been solved yet and spark fresh research.”
Memories are crucial to our daily lives. But this level of understanding of how memories are formed, stored, and reshaped later is crucial to things like decisions made in courtrooms, and even basic learning.
Just think about all the accounts of unreliable eyewitness testimony in court cases. The eyewitnesses aren’t trying to deceive anyone or show up with malicious intent. Their brains inadvertently add new information into an old memory, creating a false recollection that, to them, feels completely real.
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How a Better Understanding of Memory Creation May Improve Mental Health Treatment
But understanding how memories are malleable also holds crucial benefits for the mental health space. It comes with a great potential for the therapeutic treatment of things like phobias or post-traumatic stress disorder (PTSD), To treat these conditions, therapists can help their patients “rewrite” traumatic memories with calmer emotions.
So are our memories real? Can we trust them? Researchers found that true memories come from real-life experiences, but they also change every time our brains recall them.
Here’s how it works: The brain retrieves a memory, then enters an unstable state for six hours before it’s re-stored. This window is when the hippocampus updates, edits, or otherwise changes the memory before it stabilizes again.
This research shows that memory isn’t as accurate and reliable as we may have once thought.
“By revealing that memories are dynamic rather than fixed, this research helps us better understand why they can change and how that impacts the way we think, feel, and act,” Renault said.