Is it time to distance ourselves from Polyvagal Theory?

If you've worked with me, taken one of my courses, or used my workbooks, you've probably heard me mention Polyvagal Theory. This theory helped me in my personal health recovery and in my professional work with trauma-responsive legal practice. I want to share an update to how I discuss nervous system concepts as a lawyer and educator, and why I've decided to distance myself from that term as an umbrella framework.

What Just Happened in the Research World

A few weeks ago, an academic paper signed by 39 internationally recognized experts in neurophysiology, vagal physiology, and vertebrate evolution was published in Clinical Neuropsychiatry under the provocative title "Why the Polyvagal Theory Is Untenable." 

The paper targets the physiological underpinnings of Polyvagal Theory ("PVT"), a theory developed by psychologist Stephen Porges in the 1990s regarding human autonomic nervous system organization and functioning. 

The lead author of the new paper is Dr. Paul Grossman, Emeritus Research Director of Psychosomatic Medicine at the University Hospital Basel in Switzerland, and this paper is the culmination of nearly two decades of his published critiques of PVT. He challenged specific premises of PVT in a 2007 paper with evolutionary biologist Edwin Taylor, sharpened that critique in a 2023 paper declaring each of PVT's five basic physiological premises to be "untenable or highly implausible," and has now assembled 38 co-signatories from institutions across the world to make the case in full. This has been a long time coming!

Porges was invited to submit a rebuttal to the Grossman paper in the same journal issue this time. Spicy. In his response, Porges states that the group of scientists are misunderstanding his point of view regarding vagal functioning, because of their different perspective that is focused more on anatomy, and that their points don’t actually disprove his core theory. Porges also says that Grossman misrepresents PVT by attributing to it claims it never held or no longer holds, since modifications were made to it in various papers throughout the years. Essentially, Porges says Grossman is creating a strawman to take down. There is clearly years of animosity between these two. The debate about PVT is ongoing and unresolved at this time. 

The scope and specifics of the challenge are worth engaging with honestly.

What the New Paper Actually Argues

It's worth being precise because the online conversation has already simplified this into either "PVT is debunked" or "ignore the critics." Neither is quite accurate.

The new paper targets three specific neurophysiological claims at the foundation of PVT. Understanding what those claims are, and what the critics are actually saying matters.

The critics argue three main things. First, they say the two brainstem vagal nuclei (what many would refer to as vagus nerve pathways), the ventral vagal nucleus and the dorsal vagal nucleus, are not anatomically set up to function the way Porges describes. Their evidence does not support the idea that the ventral pathway uniquely mediates social engagement, or that the dorsal pathway drives the kind of significant freeze response PVT describes in humans. 

The authors argue that the experimental evidence does not support these functional distinctions. In mammals studied to date, including rats, cats, dogs and sheep, the dorsal nucleus has only modest or negligible effects on heart rate. The authors also cite research showing that in humans, neither emotional freezing nor psychological dissociation typically produces the significant heart rate deceleration that PVT's dorsal vagal model predicts (I will say that I have personally experienced this, but I wasn’t part of the study!). 

Meanwhile, the ventral vagal nucleus appears to be involved in both social and defensive responses, not in social engagement alone. The tidy separation in PVT between these two vagal pathways is, according to the authors, not supported by the evidence.

In his rebuttal, Porges says his PVT does not claim that when dorsal nuclei shifts to conservation (in adaptation to threats) that it results in complete cessation of ventral vagal activity and shutdown, rather, that this idea got popularized by others. 

The second critique concerns respiratory sinus arrhythmia, or RSA. RSA is the rhythmic fluctuation of heart rate in coordination with breathing, and it serves as the primary physiological measure PVT uses to index vagal tone. PVT treats RSA as a window into central vagal output from the ventral vagal pathway. The authors argue that it is not the reliable window into nervous system state that PVT claims it is.

RSA is shaped by a large constellation of factors beyond central vagal drive, including breathing rate and depth, blood pressure, sympathetic nervous system activity, age, and the heart itself.

In Porges’ response, he does not argue against those points, but says that Grossman misunderstood his viewpoint which was focused on the dynamic and observable whole-body interactions when it comes to the heart and vagus nerve. 

Third, they dispute the evolutionary story PVT tells about the vagus nerve, arguing that the anatomical features Porges describes as uniquely mammalian are actually present across many vertebrate species, including reptiles. Reptiles, far from being limited to primitive defensive responses, also exhibit complex social behaviors including long-term pair bonding, cooperative hunting, communal parenting, and social learning. The evolutionary story PVT tells is, in the authors' view, contradicted by decades of comparative physiology.

Porges’ response is that PVT claims that the vagus fibres interact with cranial motor circuits in mammals in a unique way, not that reptiles don’t have anything comparable. 

To me, it seems like Grossman and Porges are having two separate arguments, not a conversation. They are each focused on their own perspective and area of study and do not appear to be listening to what the other is actually saying, probably because they essentially speak different scientific languages. There is very little shared ground between these two, and the debate may never resolve. I would love to see them in the same room and see what happens to their nervous systems! 

What the Paper Does Not Challenge

Here is what I think is equally important: none of this critique touches the psychological and somatic concepts that most practitioners are actually relying on when they say they are using Polyvagal Theory as a lens to understand clients in their practice. 

The ideas of co-regulation, neuroception (the body's below-conscious sensing of safety and threat), the hierarchy of defensive responses, and the value of social connection for nervous system supports are not what is being challenged. Those concepts draw on decades of prior work in attachment theory, developmental psychology, trauma research, and community knowledge that predate PVT. This latest critique simply means those ideas need to stand on their own foundations, which they already do. They are empirical understandings that also have their own evidence-based backing. 

This Is Not New Knowledge

The core insight that PVT popularized in the 1990s, that our nervous systems operate in more than just two states (relaxed or fight or flight), and that connection, safety, and co-regulation are biological needs, not just psychological preferences, is an important building block in understanding human behaviour. Many communities around the world have understood for centuries that we are relational beings whose bodies respond to safety and threat, that we co-regulate one another, that healing happens in community, and that the body holds wisdom worth attending to. 

PVT gave those ideas a Western scientific framework and a clinical vocabulary that expanded their reach in many professional circles. But the knowledge itself is much older and more widely known than PVT's popularity might suggest. It is worth naming that the way this theory was packaged and promoted carries the marks of a colonial epistemology: presenting community and ancestral wisdom as though it required scientific validation to be legitimate, and crediting one main theorist with various insights that belong to many traditions and perspectives. 

The Version I Have Taught

I have never taught or promoted an uncritical version of PVT, because the popular presentation of the theory has significant problems. The mainstream presentation of PVT is quite simplified and without nuance. Many versions of PVT are ableist. The hierarchy of states is often presented as a ladder from dysfunction to health in ways that pathologize entirely reasonable responses to genuinely unsafe environments, and that do not properly account for neurodivergent nervous systems or the chronic stress responses that marginalized communities navigate as a matter of daily life. 

That framing has never reflected how I understand this material, so I reworked it in a way that actually made sense (with deep self-directed study and course work), and made a new map to understand it. My Nervous System map integrates well with other practices like somatics, Parts work, cultural practices, and spirituality. I chose not to focus on the neurophysiological or anatomical underpinnings as much, in part because prior critiques had already given me reason for caution, and I leaned on empirical experience instead. 

What I have found genuinely useful, and what the 2026 paper does not challenge, is the recognition that our nervous systems are more complex than a simple binary of relaxed versus fight-or-flight. The expansion to three primary states, and several mixed states in between, each with their own adaptive function, gave many people a more honest and compassionate map of their own experiences. I never liked the language of “dysregulated” and “regulated”, but was more interested in supporting our various nervous system states and what they ask of us. That expansion and focus on flexibility and capacity remains valuable regardless of the current arguments.  

I made a directory of resources that I found helpful in my own health recovery journey, which includes books from authors such as Deb Dana, who worked with Stephen Porges, but has a different and more accessible framework for understanding the nervous system. 

What I Am Changing

The physiological underpinnings of PVT are in dispute (and not resolved) in academia and thus many people no longer trust the theory as a whole. The human insights at its core, that our bodies seek safety, that we co-regulate each other, that our adaptive responses make sense in context, are not in dispute at all. They predate PVT and will outlast this debate.

I don’t think I need to anchor my teaching to a theory whose specific scientific claims are under challenge when the underlying wisdom stands perfectly well on its own. Maybe I never needed to focus so much on PVT, but it was what I found helpful at the time of my own health recovery. 

What I am actually discussing in my trauma-responsive lawyering work could simply be described as Nervous System Theory and Frameworks, and that is what I will focus on. It will continue to include references to PVT, and other theories, modalities, and evidence as well. I have updated my workbooks and teaching aids, such as my Nervous System Map to reflect this change. 

How I discuss the nervous system with students and in my work with lawyers and other professionals will change somewhat, to acknowledge the broader lens I am using. I'm sure it will keep changing, especially as I lean into more land-based teachings. 

This is not a crisis. We will keep discussing PVT. Theories are supposed to be revised when evidence challenges them. The map was always imperfect. I am just giving it an update. 

If you have questions about what this means for resources you've received from me (the new ones are available for download via your email!), or how it changes the frameworks I work with, I'm happy to talk through it.

 

Thanks for reading! I'm Alanna Carlson, a Saskatchewan-based lawyer, consultant, educator and investigator who does workplace assessments, investigations, trainings and neuro-inclusive professional coaching! I teach a law school seminar and professional courses on trauma-responsive legal practice. I also design helpful wellbeing resources that I used to recover from chronic illness; visit my shop!

Sources: 

Grossman, P., et al. (2026). Why the polyvagal theory is untenable: An international expert evaluation of the polyvagal theory. Clinical Neuropsychiatry, 23(1), 100–112. https://doi.org/10.36131/cnfioritieditore20260110

Grossman, P. (2023). Fundamental challenges and likely refutations of the five basic premises of the polyvagal theory. Biological Psychology, 180, Article 108589. https://doi.org/10.1016/j.biopsycho.2023.108589

Grossman, P. (2024). Respiratory sinus arrhythmia (RSA), vagal tone and biobehavioral integration: Beyond parasympathetic function. Biological Psychology, 186, Article 108739. https://doi.org/10.1016/j.biopsycho.2024.108739

Grossman, P., & Taylor, E. W. (2007). Toward understanding respiratory sinus arrhythmia: Relations to cardiac vagal tone, evolution and biobehavioral functions. Biological Psychology, 74(2), 263–285. https://doi.org/10.1016/j.biopsycho.2005.11.014

Menuet, C., et al. (2025). Redefining respiratory sinus arrhythmia as respiratory heart rate variability: An international expert recommendation for terminological clarity. Nature Reviews Cardiology, 22, 978–984. https://doi.org/10.1038/s41569-025-01160-z

Porges, S. W. (2025). Polyvagal theory: Current status, clinical applications, and future directions. Clinical Neuropsychiatry, 22(3), 169–184. https://doi.org/10.36131/cnfioritieditore20250301

Porges, S. W. (2026). When a critique becomes untenable: A scholarly response to Grossman et al.'s evaluation of Polyvagal Theory. Clinical Neuropsychiatry, 23(1), 113–128. https://doi.org/10.36131/cnfioritieditore20260111