Does a memory coming up mean something is wrong?

No. In this research, a memory returning to an active state was the very thing that made it possible to change. A memory surfacing in a session is common, and it can be an opening rather than a warning. If it feels overwhelming, reach out to your care team.

Can old memories actually be changed once they surface?

The study suggests a reactivated memory can enter a state where it is open to updating, at least for a simple learned fear in the lab. That does not mean a memory is erased. It means the feeling attached to it may be reshaped when it is met with a new experience.

Immersion

Why do old memories come up during a session?

Q: Why is it not enough to just remember something to change it?

This study found that simply calling a memory back to mind did not update it. The memory only softened when the moment carried a surprise, a mismatch between what the person expected and what happened. In plain terms, meeting a memory in a new way matters more than replaying it.

Short answer

Old memories often surface during a session because a session reactivates them, and a reactivated memory can become open to change rather than just replay. A 2012 fear-memory study found that retrieval alone does not update a memory. It is the surprise of a new experience during retrieval that opens the door.

The research

Sevenster, D., Beckers, T., & Kindt, M. (2012). Retrieval per se is not sufficient to trigger reconsolidation of human fear memory. Neurobiology of Learning and Memory, volume 97, issue 3, pages 338 to 345.

Sample Healthy adult volunteers in a laboratory fear-conditioning experiment, measured with the eyeblink startle response. This was a study of a simple learned fear in the lab, not of the personal memories that surface in a therapy or psychedelic session.

Published 2012

Journal Neurobiology of Learning and Memory

In 2012, Dieuwke Sevenster, Tom Beckers, and Merel Kindt set out to test a simple but important idea about memory. When a memory comes back to mind, does it automatically become open to change? To find out, they first taught healthy volunteers to fear a harmless image by pairing it with a mild electric shock, a standard laboratory method. The next day, they brought that memory back in different ways. Sometimes they showed the image and nothing happened, which broke the person's expectation of a shock. Other times they arranged things so there was no surprise at all. They tracked fear with the eyeblink startle response, a quick automatic flinch that rises when a person is on edge. The result was clear. Simply calling the memory back to mind was not enough to change it. The memory only became open to updating when the moment carried a surprise, a mismatch between what the person expected and what actually happened. The researchers called this mismatch a prediction error. Without it, the old fear stayed locked in place. With it, the memory softened and could be reshaped.

Read the paper

What does this mean for you?

If an old memory rose up during a session, this research offers a way to understand why it might matter. A memory that surfaces is a memory that has been reactivated, brought back into an active state. And a reactivated memory is not fixed in stone. In this study, that active state was the moment when the old learning could be changed. So a memory coming up is not just the past repeating itself. It can be the point where the past becomes workable.

It is worth being honest about what this study can and cannot say. It looked at a simple fear learned in a laboratory, not at the rich personal memories that come up in therapy or a deeper session. It measured an automatic flinch, not the felt weight of a memory. And it was small. So treat it as a clear look at one mechanism, how a reactivated memory can open to change, rather than a full account of why any particular memory surfaced for you.

Still, the direction is useful. The study points to why what happens around a resurfacing memory matters so much. The memory alone changes little. It is the new experience laid alongside it, the surprise of meeting it differently, with support and in a safer place, that gives the old memory a chance to shift. That is why a memory coming up in a session, rather than being pushed back down, can be an opening instead of a setback.

The takeaway

A memory surfacing in a session is that memory being reactivated, which can be the moment it becomes open to change.
The memory on its own changes little. What matters is the new, different experience you meet it with.
If hard memories come up, that is not a sign the work is failing. Bring them to your care team so you meet them with support.

Terms in this page

Window of neuroplasticity Integration Grounding

This is the work Asendar™ was built for: staying with you after a memory surfaces, so what came up in a session gets met with reflection and support in the days that follow, rather than pushed back down. If you want a simple read on where your head is today, take your Mental Readiness Score.

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