How the Brain Creates Alters: The Neuroscience of DID
(Summary) What exactly is an “alter” in dissociative identity disorder (DID)? Alters aren’t random inventions—they’re rooted in how the brain develops neural networks in response to repeated experiences. In everyday life, everyone builds different “parts” of themselves to handle different roles, like being a parent, worker, or friend. The difference in DID is that early trauma interrupts the integration of these neural networks, leaving some disconnected from each other. Instead of all being experienced as one “me,” these parts can feel and function like distinct identities, each with their own memories, skills, and perspectives. Understanding alters this way—through neuroscience and lived experience—shows that DID isn’t mysterious or imaginary. It’s the brain adapting to survive.
Have you ever wondered what an alter is? Or why you have alters and most other people don’t? I’m going to share my understanding of this with the caveat that I am not a neuroscientist, and this is my interpretation of the studies I’ve read.
In neuroscience, there is a famous statement: “neurons that fire together wire together.” A group of neurons are repeatedly activated together, these cells become more connected and form a neural circuit. More complex wiring of more neurons leads to a neural network. And very large groups of neurons wired together are called large scale brain networks. You have, for example, a neural network for tying shoes. If you practice and develop the skill of juggling, you will have a neural network for juggling.
It’s possible that a neuroscientist would correct me and tell me that these are actually large scale brain networks rather than neural networks. The point is when you learn, rehearse, or repeat something over and over, it creates a group of connected neurons, and the more neurons that are involved, more complicated it becomes. So that the connected neurons grow from a neural circuit to a neural network to a large scale brain network.
The brain creates these networks because it assumes that things we do repeatedly are important, and creating this network for this task makes it easier perform the task. That’s why when you’re learning to play the piano, it’s so much slower and harder than after years of practice. Then you can play songs by memory with your eyes closed. Practice has created neurons wired together to carry out a particular task.
I’m sure you’ve heard people talk about different roles they play in life as wearing different hats. Someone says they’re putting on their worker hat. As they go to work. Or their parent hat when they come home from work. Someone might put on their coaching hat they go coach Little League baseball. Of course, we don’t mean they are literally putting on or changing the hats they wear. It’s the mindset of a role.
The expectations a person has to meet at work are really different from the expectations of a youth coach or a parent, for example. People tend to develop parts of ourselves to kind of specialize in these different roles. They are all parts of ourselves, not separate parts. But it would be pretty awkward to bring your romantic partner self to work. Right? Or if your partner flirts with you to respond with your youth coaching role.
These hats or parts are ourselves optimized to meet various situations, expectations, and needs. It’s like putting on a different tool belt for each role. If I wear my parenting tool belt to work, I might not have everything I need for dealing with work easily at hand. So we get the skills and viewpoints we need prepared for the situation we’ll be in.
Now let’s consider DID. It happens early in childhood. Generally no later than age five or six. DID is the result of an interruption of integration of various experiences because of trauma. It is the same child experiencing a variety of experiences, good and bad. But they begin to develop parts that can specialize particular situations or emotions. That’s no different from what I’ve just described about having a parent part a worker part, a coaching part, or a romantic part.
Here’s where it gets different: If we think of these parts that specialize in various roles or situations or emotions, as neural networks or large scale brain networks, in a person who does not have DID, the many neural networks are connected to each other. So that the person experiences all of these different parts as “myself.” But with ongoing trauma for a child, they are not able to make the connections between each network. Some networks are connected a little bit. These are alters that may be aware of each other, and maybe they can communicate. Some alters are very much separated and may not be known by others. In DID, the parts of consciousness are not connected enough to feel like they are all different expressions of the same person. And over time, these neural networks may become even more independent and more developed through experiences so that they feel like entirely separate entity with their own memories and skills and their own likes and dislikes within that person.
Studies looking at the brain with fMRI, functional MRI, have been able to distinguish between alters based on the neural networks that light up each one. And importantly, when the brains of actors who have been tasked with doing their best to simulate DID are studied by the fMRI, these different networks are not seen. That’s because they aren’t there.
I want to say that I hope this doesn’t feel reductionistic. It’s certainly a simplification an incredibly complex set of interactions. The brain is amazing and the most complex thing in the universe. We are all collections of neural networks and large scale brain networks, when you get right down to it. But that is a description that really doesn’t do justice to our experiences of ourselves and our lives. So I hope if you have DID, you don’t hear me saying you’re just a neural network as that as if I’m minimizing. You might be. But so are we all. Personally, I find that it helps me to understand so much better what is happening not only with my clients, but with myself. Since I too am a collection of neural networks. It explains why, at the same time, I can feel like part of me wants to go out to some event. And part of me wants to get cozy on the couch with a bowl of popcorn and a movie. In a person with DID, these would be experienced as separate alters. For someone without DID, these parts are both experienced as “me” ven though they’re very different feelings or urges or wants. So I hope this helps you understand a little better what an alter is and how they happen.
Frequently Asked Questions
What is an alter in DID?
An alter is a distinct part of self in Dissociative Identity Disorder, with its own memories, emotions, and roles, formed in childhood as a survival response to trauma.
How are alters different from normal life (non-DID) roles?
Unlike everyday roles (parent, worker, partner), alters in DID are separate neural networks that aren’t fully connected, making them feel like distinct identities rather than one unified self.
When does DID usually develop?
DID typically develops before age six, during early brain development, when repeated trauma interrupts the normal integration of experiences.
How does trauma cause alters to form?
Chronic childhood trauma prevents different neural networks from connecting. Instead of integrating, these separate networks develop into alters that hold specific roles and memories.
Is there scientific evidence for DID?
Yes. Brain scans (fMRI) show that alters activate distinct neural networks. People simulating DID do not show these patterns, proving DID is neurologically real.
How is DID different from acting or pretending?
Actors may role-play, but their brains remain integrated. In DID, separate alters activate unique brain networks, showing the difference is genuine, not performance.
Does describing alters as neural networks minimize their reality?
No. The neural network explanation shows how DID develops in the brain, but alters remain real, lived experiences that affect memory, behavior, and healing.