The Science Under Therapy: What the Polyvagal Theory debate means for your healing

A perspective from a mental health counselor who loves Gossip Girl and did not expect to spend this much time reading neuroscience papers

If you've spent any time in trauma-informed therapy over the last decade or two, you've probably heard something like this: "When you feel frozen and can't move or speak, that's your nervous system going into shutdown mode. It's a survival response, not a character flaw."

That explanation, the one that helped so many people stop blaming themselves for their trauma responses, comes largely from something called Polyvagal Theory.

Currently, Polyvagal Theory is under heavy scrutiny by exactly 39 scientists who recently published a paper in an academic journal, citing detailed reasons for why this theory isn’t entirely accurate. For a nerdy therapist like me, this is better than reality tv. It’s incredible, and here’s why you should find it incredible too. 

Wait, Back Up. What Even Is Polyvagal Theory?

In 1994, neuroscientist Dr. Stephen Porges proposed a new way of understanding the vagus nerve, a long nerve that connects your brain to your heart, lungs, and gut and plays a huge role in how your body physically responds to and manages stress. 

Before Porges came along, we understood the nervous system like a pretty basic video game controller: one button for "GO" (fight-or-flight) and one button for "STOP" (rest and calm). Porges said, actually, there's a third button: a social engagement system, unique to mammals, that helps us connect with other people, feel safe, and regulate our emotions through our relationships.

He also proposed that these systems evolved in layers, like a geological core sample of your nervous system. When danger hits, you move through them in reverse order. Mild threat? Fight-or-flight kicks in. Completely overwhelming, inescapable terror? Your most ancient layer takes over and you go into freeze. 

Trauma therapists ran with this. And honestly? It made sense. It gave therapists and clients a common, biological language for the most confusing and shame-soaked experiences of their lives. You didn't freeze because you were weak. Your nervous system made an ancient, involuntary calculation. In an individualistic society that values productivity over wellbeing, this message was a comfort.

It spread through trauma treatment, yoga studios, somatic therapy, breathwork retreats, and eventually every wellness podcast that has ever existed. Which, as we will see, is where things got a little complicated.

So what's the Tea?

Earlier this month, a group of 39 researchers consisting of neuroanatomists, physiologists, and evolutionary biologists  published a paper titled, "Why the Polyvagal Theory is Untenable."  Thirty-nine experts. Signing their names. On a paper that is essentially a very long, very footnoted way of saying "-XOXO, Gossip Girl”

Their main issues come down to a few things:

1. The anatomy doesn't check out. Polyvagal Theory depends on two branches of the vagus nerve doing very distinct, separate jobs, one handling your ancient freeze response, one handling your social connection system. The critics say the actual wiring of the human body doesn't support this clean division. They went looking for the neat anatomical architecture the theory requires and found, unsurprisingly, that similar to the human experience, our anatomy doesn’t fit into a perfect shape in a perfect box. 

2. The measurement tool is shaky. A lot of polyvagal research leans on something called Heart Rate Variability (HRV), or the rhythmic fluctuation in your heartbeat as you breathe. Higher HRV supposedly signals that your "social engagement" system is humming along. But critics say this is like apples and oranges. They're related, but you're not measuring what you think you're measuring. Slow your breathing down and your HRV goes up, not because your nervous system transformed, but because you slowed your breathing down.

3. The evolutionary story has some plot holes. The theory positions social behavior as a uniquely mammalian superpower, made possible by this evolved ventral vagal system. Unfortunately for Porges’s theory, mammals are not the main characters that we like to believe they are. It turns out reptiles do engage in complex social behaviors. Evolutionary biologists in the paper compare crocodile’s pair bonding and cooperative parenting to that of mammals. 

4. Porges mostly only cites himself in his research findings. When you look at his theory and its supporting data, he refers to his own research papers that he previously published. Instead of using a broad range of evidence from different angles, he basically says, “Because I said so.” The few papers that he does cite are misrepresented or misquoted- a major red flag in the scientific community.

Okay, But What Does Porges Say?

He responded. At length. In the same journal. Which, honestly, respect.

Porges argued that his critics fundamentally misread the theory. He says that it was never meant to be a rigid anatomical blueprint, but a systems-level framework for understanding how our physiological states shape our behavior and experience. He also pointed to newer research he says supports the functional distinctions he's been describing all along.

He also made a point that I think deserves its own moment: a lot of what's being criticized is not actually his theory. It's the simplified, telephone-game version that spread through the popular wellness world, shedding nuance at every stop along the way until it became a kind of nervous system mythology. He's being held accountable for things that happened to his ideas after they left his hands, which, if you've ever watched someone misquote you on the internet, you know is a specific kind of frustrating.

HOWEVER. As Dr. Birthe Macdonald points out in her substack, the 39 writers of Porges’s critique use direct quotes from his studies. It does make me wonder... if his own direct quotes can be so severely misunderstood by the leading experts in the field, how are the non-academics of the world supposed to understand them? It seems suspicious that the only person able to decipher the theory is the theorist himself. In addition, if the theory is just a framework and not a biological explanation, then Porges ideas on trauma and stress response are nothing new. So why is he treating it like a scientific breathrough?

So Should You Be Spiraling Right Now?

No. Please don't. 

Here is the part that genuinely matters: even the 39 scientists who called the theory "untenable" acknowledged, near the end of their paper, that the clinical concepts at the heart of polyvagal-informed therapy don't actually depend on the neuroscience being perfectly correct.

The importance of feeling safe in your body. The power of connection and co-regulation. The understanding that trauma responses are involuntary survival mechanisms and not personal failures. Those ideas have deep roots in decades of attachment research, trauma psychology, and relational neuroscience that predate Polyvagal Theory entirely.

What this debate probably should change is how therapist's value evidence-based treatment in our clinical practice. Books like The Body Keeps the Score have their place, but not in a "this is life changing truth" sort of way (maybe one day I'll write a post on all the reasons I hate that book and the guy who wrote it). We need to be more critical of what theory really is- an idea. For the case of Polyvagal Theory, there's a difference between using it as a flexible, humanizing metaphor to help people make sense of their nervous system, which it does genuinely well, and treating it as established, precise neuroscience, which it is not. Your therapist telling you "that freeze response makes sense, your nervous system was trying to protect you" is still true and still helpful.

What this debate should not change is the actual work of healing. Helping trauma survivors feel safe in their bodies. Slowing down. Using breath and movement and relationship to build capacity. Learning to tolerate difficult feelings without being swamped by them. None of that loses its value because some scientists are having a Very Intense Academic Disagreement.

Here's the Part Where I Tell You That Science Being Messy Is Normal

I know it's unsettling when a framework that helped you feel understood turns out to be contested. We want the foundations of our treatment to feel reliable and consistent.

But this is actually science working exactly the way it's supposed to. Researchers challenge each other. Theories get stress-tested. The parts that hold up survive; the parts that don't get revised. The fact that 39 scientists felt compelled to put their names on a critique, and that Porges came back swinging with detailed rebuttals, means the field is taking itself seriously.

Polyvagal Theory may not survive in its current form. It will probably be significantly revised over the next decade. Something more anatomically precise may emerge to replace or refine it. That's not a crisis, that's the scientific process.

What I'm confident will survive is the thing that mattered most all along: the recognition that people who experience trauma are not broken, that their bodies responded exactly as bodies do under impossible circumstances, and that healing happens, messily and imperfectly, through safety and relationship. 

That truth isn't going anywhere. Not even 39 scientists can touch it. -XOXO, your local mental health counselor. 

Questions about how this affects your own therapy? Bring them to your next session. Uncertainty is actually a pretty great thing to explore together.

Special acknowledgments to Dr. Berthe MacDonald and her Journal Club- you make complicated neurological research accessible to this author. Thank you.