Evolution of a Theory: Polyvagal is Not Dead

A measured response to the debate between Porges and Grossman

I’ve been studying Polyvagal Theory (PVT) from primary sources and secondary summaries for about 5 years. This framework has allowed me to make sense of my own trauma symptoms and befriend my nervous system instead of working against it. I use PVT daily in my self-care strategies and in my relationships and community.

I’ve tracked criticisms of Polyvagal Theory, including Grossman’s opposing viewpoint on ResearchGate, since I first became aware of PVT. Over the last year or so, I’ve seen the online debate around Porges and Grossman and their ideas grow into a heated argument, with the end result being that many have dismissed PVT out of hand rather than examining the arguments for truth.

It’s taken me many months to organize my ideas on this topic, but I’m finally ready to share my perspective. This is not a perspective developed in isolation, but through conversations with researchers, clinicians, and trauma survivors. I especially want to thank psychotherapist Sarah Schlote for contributing to my understanding of this topic.

First, Polyvagal Theory is not just a theory. PVT is a working model of the Autonomic Nervous System. It’s not the only model that exists, but it is the most well known. There are 4 other current working models of the nervous system: the Neurovisceral Integration model, the Biological Behavioral model, the Resonance Frequency model, and the Psychophysiological Coherence model. In my opinion, these models are complementary rather than competing explanations. These models of the nervous system are used as maps to understand the terrain of the human nervous system.

Second, Polyvagal Theory has not been debunked. Grossman has some legitimate criticisms of fringe elements of the theory, but the core of aspects of Polyvagal theory are proven in clinical practice daily. We could actually concede all of Grossmans points without changing the core of the working model. I’ll get to his points in a minute, but first let’s look at the actual core concepts of PVT: Hierarchy, Neuroception, and Co-regulation.

Hierarchy refers to the order in which our bodies activate the 3 neural circuits of the Autonomic Nervous System (the ventral vagus complex, the sympathetic adrenal system, and the dorsal vagus nerve complex). Neuroception is the body’s ability to sense danger or safety in our environment and cue the activation of the 3 neural circuits. Co-regulation is the ultimate safety signal wherein resonance with another nervous system allows us to engage the ventral vagus nerve complex.

Polyvagal theory is not dead yet. PVT is evolving from what Porges first conceptualized. Many pieces of the theory need to be updated to reflect new scientific understandings. Because PVT is a scientific model or map, it should be adjusted when we discover new facts. In response to this debate, Porges has pointed out that a scientific model cannot be discarded completely until a better working model is presented.

For those that are interested in the details, let’s look at the 3 aspects of Polyvagal Theory that have been criticized the most and how we can update them for a more accurate working model.

Premise 1. Respiratory sinus arrhythmia is regulated by the ventral branch and neurogenic bradycardia by the dorsal branch. These branches can operate independently of each other.
Update: The dorsal branch has been shown to have little effect on heart rate. These branches operate together in a rhythmic pattern rather than completely independently.

Premise 2. There is a phylogenetic hierarchy of the two main branches of the vagus, dorsal and ventral. The dorsal vagus is a vestigial relic of the reptilian brain and is responsible for neurogenic bradycardia.
Update: The hierarchy of mammalian nervous system responses is not based on phylogenetic evolution. We do not have a reptilian brain.

Premise 3. The ventral vagal branch is a uniquely mammalian adaptation that allows mammals to detect novelty, actively engage with the environment, and socially communicate.
Update: Some non-mammalian animals (lizards!) have a unmyelinated ventral vagus nerve. Myelination around the ventral vagus is a uniquely mammalian adaptation.

There are some other aspects of PVT that I believe are even more important to correct than these details.

• The concept of faulty neuroception is often taught in a pathologizing and potentially harmful way. Neuroception is only faulty when safety is perceived as dangerous. Highly attuned neuroception or sensitivity to real and perceived danger is not faulty, it is an adaptive neurodivergent trait that can be a strength if our neurological differences are well supported.
• Porges has hypothesized that fawn is a ventral vagus response to non-life-threatening danger, which demonstrates a lack of understanding of power dynamics. Fawn is more accurately explained by Nkem Ndfoe as a mixed sympathetic and dorsal state that occurs when social power dynamics invoke existential threat.
• Throughout the literature on PVT, you may encounter the false assumption that dorsal vagus over-activation is a symptom of being autistic or that sympathetic over-activation is a symptom of ADHD. These are actually symptoms of trauma in neurodivergent individuals, not inherent traits of our neurotype.

None of these changes alter the 3 core concepts of PVT: Hierarchy, Neuroception, and Co-regulation. If science reveals these 3 ideas to be incorrect, then Polyvagal Theory will be dead. I doubt that will happen, but I am very open to being surprised by new discoveries.

Finally, let’s look at the difference between PVT and a polyvagal framework. A polyvagal framework is more expansive than the theory itself. A polyvagal framework incorporates the core elements of Polyvagal Theory along with other tangential science about the nervous system.

In many cases, when a person says “polyvagal” they are not only referring to Porges theory as it was introduced in 1994, but also referencing a larger schematic which integrates PVT with attachment theory, research on emotional regulation, psychological stress models, and the other 4 models of the nervous system. (This is true for my blog The Polyvagal Neurodiversity Project.) The growing popularity of the polyvagal framework has been dismissed as “pop science,” but I believe it is popular with clinicians and survivors because of its implicit inclusion of other theories of neuroscience. In a polyvagal framework, PVT is an anchor concept that ties all these other theories together.

In conclusion, I want to consider our ways of knowing and how we verify truth. The polyvagal framework has been criticized as “only of value in the clinical practice,” as if this is a problem. But to me, if something is truly valuable in clinical practice, it is infinitely useful. Experiences in clinical practice ripple out to all of our relationships including our relationships with self, friends, family, and work. That is no “only” in my book.

In addition to being validated by current neuroscience, the core concepts of Polyvagal Theory can also be verified by lived experience. This way of knowing is often judged as inferior in western culture, but there are other cultures who value the deep wisdom of the body more than we do. When I first encountered these ideas, it was easy to recognize the truth in Hierarchy, Neuroception, and Co-regulation because I have experienced proof of these throughout my life.

I am not here to tell you what to do with Polyvagal Theory. It is up to you to decide if it’s useful for you or not. I for one will not be discarding it. I will simply keep updating it until the framework is no longer useful for me.

Trauma Geek, aka Janae Elisabeth, believes nervous system education will change the world. You can learn about polyvagal theory and the nervous system for free here: linktr.ee/TraumaGeek. This work is made possible by patron members at www.patreon.com/TraumaGeek. If you’d like to learn more 1-on-1, you can book a time to chat with Trauma Geek here: www.calendly.com/TraumaGeek.