How We Rewrite Our Own Memories

Have you ever argued with a friend about what exactly happened at a party five years ago? You’re sure he offended you with a joke, but he swears it never happened. And you’re both sincere. This isn’t just about bad memory—it’s about how the brain constantly "edits" the past. The process is called memory reconsolidation, and it explains why eyewitness testimony in court sometimes falls apart, and why PTSD therapy works by literally rewriting trauma.

What Is Reconsolidation and Why Memories Aren’t Stone but Play-Doh

When you first experience an event, the brain encodes it into short-term memory. Then, if the memory is important or emotional, it moves to long-term storage through a process called consolidation. Scientists used to think: once a memory is "saved," it’s stable, like a file on a hard drive.

But in the 2000s, neuroscientists discovered something wild: every time you recall something, the memory is pulled from the archive, becomes vulnerable, and gets rewritten. That’s reconsolidation. In that moment, the brain can add new details, remove old ones, or shift the emotional tone.

In simple terms: a memory isn’t a video recording—it’s a draft you edit every time you open it.

The study that proved it: Karim Nader’s experiment at McGill University in 2000. Rats were trained to fear a tone because it was followed by a mild shock. Then researchers injected a drug that blocks protein synthesis in the brain—the exact process needed for "rewriting" a memory. Result: the rats effectively forgot the fear after hearing the tone again. Conclusion: memories can be erased or altered while they’re "open."

• Nader, K., Schafe, G. E., & LeDoux, J. E. (2000). Fear memories require protein synthesis in the amygdala for reconsolidation after retrieval. Nature, 406(6797), 722–726.

Why Witnesses Get It Wrong—And It’s Not Their Fault

In court, an eyewitness says: “I saw him pull the trigger.” A year later on cross-examination, details shift: “Maybe it was someone else.” Judges get frustrated, but science says: this is normal.

Elizabeth Loftus, one of the most famous memory researchers, ran an experiment. She showed people a video of a car crash, then asked: “How fast were the cars going when they smashed into each other?” or “...when they bumped?” Those who heard “smashed” estimated higher speeds and even “remembered” broken glass that wasn’t there.

Conclusion: one word during recall can insert a false detail into a memory. This is called the misinformation effect.

• Loftus, E. F., & Palmer, J. C. (1974). Reconstruction of automobile destruction: An example of the interaction between language and memory. Journal of Verbal Learning and Verbal Behavior, 13(5), 585–589.

How This Is Used in PTSD Therapy

Someone with PTSD relives an explosion or assault every time they remember it—with the same fear, racing heart, and sweat. Each recall is a chance for the brain to strengthen the trauma.

But there’s a flip side. Therapists deliberately activate the memory (e.g., asking for a detailed retelling), then introduce new, safe information: “You survived. You’re safe now. It’s in the past.” The brain rewrites the memory with less emotional intensity, decoupling the frightening event from the panic response.

This is the core of reconsolidation therapy and part of EMDR (Eye Movement Desensitization and Reprocessing). A 2017 review of research (referenced in Shapiro's book) found that after 6 EMDR sessions, PTSD symptoms disappeared or significantly weakened in 77% of veterans.

• Shapiro, F. (2017). Eye Movement Desensitization and Reprocessing (EMDR) Therapy: Basic Principles, Protocols, and Procedures (3rd ed.). Guilford Press.

A Wild Real-World Fact

In the U.S., studies of DNA exonerations (many involving cases from the 1980s and 1990s) revealed that eyewitness misidentification was a contributing factor in around 70% of wrongful convictions. DNA evidence freed people who had been jailed based on sincere, but incorrect, memories. Today, while eyewitness accounts are still permitted, U.S. courts are far more cautious, and defense teams often use expert testimony to explain the science of memory to juries.

What This Means for You

• Don’t trust your memories 100%. Especially emotional ones.
• Photos, videos, and journals are the best way to preserve the "original draft" of an event.
• If a memory hurts and interferes with your life—don’t avoid it, but don’t “replay” it endlessly either. See a trauma therapist who understands these mechanisms.
• Next time you argue with someone over a “memory,” remember: you might both be right, in a way. You just have different drafts.

In short: Every recall is a chance to change a memory. The brain doesn’t lie. It just updates the version to match who you are now. That’s not a weakness. It’s an evolutionary superpower—and the reason we sometimes live in different realities.