I am not a neuroscientist. My formal research training concluded more than three decades ago when I completed my Master’s thesis. I do not run a laboratory, record vagal nerve activity, or publish in autonomic physiology journals.
What I bring instead is clinical exposure: more than 57,000 hours in government practice — where I have been employed as a Psychologist, Clinical Psychologist, and Senior Specialist Psychologist — and over 12,000 hours in private practice, spent sitting with distressed nervous systems in all their forms. Across these decades, I have worked with traumatised children, overwhelmed parents, dissociated adults, hypervigilant veterans, and families caught in cycles of rupture and repair.
My perspective is therefore clinical rather than anatomical.
Recent scholarly critiques, most prominently the commentary by Grossman and colleagues, argue that Polyvagal Theory (PVT) is “untenable” on neurophysiological and evolutionary grounds (Grossman et al., 2026). Their objections focus on the interpretation of respiratory sinus arrhythmia (RSA), the functional differentiation of brainstem vagal nuclei, and the precision of certain evolutionary formulations. These are legitimate scientific questions.
Measurement validity and anatomical specificity matter within laboratory science. However, the central clinical question is different.
Before encountering Polyvagal Theory, my work was largely organized through cognitive, behavioural, and attachment-informed paradigms. Dysregulated behaviour was conceptualised in terms of distorted thinking, maladaptive learning, personality structure, or insecure attachment. Interventions focused on reframing, exposure, behavioural shaping, and narrative processing.
Much of this work was helpful.
Yet there were recurring moments — particularly with trauma survivors and highly reactive children — when cognitive strategies did not land. Insight was present. Motivation was genuine, and yet regulation was absent. The body remained braced; the nervous system remained on guard.
In those states, individuals do not reliably access the very cognitive tools they have learned. When defensive physiology dominates, higher-order cortical processes become functionally constrained. This is not a failure of insight or willpower. It is state-dependent neural availability.
Polyvagal Theory did not provide me with a new technique so much as a new organising lens. The central clinical proposition — that autonomic state functions as an intervening
platform shaping perception, emotion, and behaviour (Porges, 2026) — reorganised how I practised.
I began asking different questions:
What autonomic state is organizing this person’s experience right now?
Is this behaviour emerging from mobilised defence or protective shutdown?
Are we attempting cognitive engagement in a nervous system that is physiologically unavailable?
What adaptive function might this response be serving within a broader defensive hierarchy?
Intervention shifted accordingly. Regulation preceded reflection, and relational safety became the primary focus. My own capacity for co-regulation became central to the work.
Clinical engagement then changed. Parents became less punitive, more curious, and shame diminished. Traumatised clients developed language for physiological shifts previously interpreted as personal failure. Children described as “oppositional” were more accurately understood as frightened and mobilised. Dissociation was reframed as adaptive protection rather than a sign of weakness.
The recent critique devotes considerable attention to limitations of RSA as a precise index of central vagal outflow (Grossman et al., 2026). From a physiological measurement standpoint, this discussion is important. In clinical practice, however, therapeutic shifts do not depend on biomarker precision. They depend on recognising that physiological state organizes relational and behavioural capacity.
Importantly, what is clinically central in Polyvagal Theory — that shifts in autonomic state shape how we perceive, feel, and relate — was not empirically falsified in the critique. The primary debate concerns the interpretation of specific physiological mechanisms and evolutionary framing. Those distinctions matter.
Readers interested in a detailed scholarly response are encouraged to review Porges’ rebuttal (Porges, 2026) and the Polyvagal Institute’s critical discussion page, which provides context and clarification regarding the foundational science of the theory (Polyvagal Institute, 2026).
I have observed similar patterns of scientific debate across my professional lifetime. In the early 1990s, when I trained in EMDR under Shapiro, the method was widely questioned and its mechanisms poorly understood. Scepticism was strong, yet in clinical practice, meaningful shifts were observable. Over time, research refined the underlying explanations and the method became integrated into mainstream trauma treatment. Mindfulness-based interventions and attachment theory underwent comparable periods of scrutiny before achieving broader scientific consolidation. In each instance, clinical utility and mechanistic clarification progressed in parallel rather than in opposition.
It may be helpful to distinguish levels of explanation.
At one level are observable clinical patterns: humans shift between connection, mobilisation, and collapse, and these shifts are visible, repeatable, and therapeutically consequential.
At another level lies the organising systems model: autonomic state functions as a regulatory platform shaping perception and relational capacity (Porges, 2026).
At a third level are the anatomical mechanisms — the specific nuclei, fibre types, and evolutionary pathways that generate these states.
The current controversy operates largely at the third level. Clinicians necessarily work primarily at the first and second. Refinement at the anatomical level does not negate the observable and therapeutically relevant reality that state organizes behaviour.
Clinical frameworks often precede full mechanistic clarity. Mechanistic refinement does not invalidate clinically observable patterns; it sharpens understanding over time.
I am not claiming that every anatomical assertion within Polyvagal Theory is beyond revision. Nor am I dismissing the importance of physiological precision. I am claiming that organizing therapeutic work around autonomic state has consistently deepened clinical engagement and improved regulatory access across decades of practice.
The debate over mechanism will continue, as it should. Meanwhile, frightened nervous systems still calm in the presence of safety. Parents still soften when dysregulation is reframed as protection rather than defiance. Trauma treatment still benefits when regulation precedes reflection.
Scientific models evolve through refinement, and clinical practice proceeds in parallel. These domains need not be in opposition.
Paul North,
Psychologist|Author, Polyvagal Parenting
References
Grossman, P., Ackland, G. L., Allen, A. M., Berntson, G. G., Booth, L. C., Burghardt, G. M., Buron, J., Dinets, V., Doody, J. S., Dutschmann, M., Farmer, D. G. S., Fisher, J. P., Gourine, A. V., Joyner, M. J., Karemaker, J. M., Khalsa, S. S., Lakatta, E. G., Leite, C. A. C., Macefield, V. G., … Zucker, I. H. (2026). Why the polyvagal theory is untenable: An international expert evaluation of the polyvagal theory and commentary upon Porges, S. W. (2025). Polyvagal theory: Current status, clinical applications, and future directions. Clinical Neuropsychiatry, 23(1), 100–112. https://doi.org/10.36131/cnfioritieditore20260110
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–
- https://doi.org/10.36131/cnfioritieditore20260111
Polyvagal Institute. (2026). Critical discussion of polyvagal theory.https://www.polyvagalinstitute.org/criticaldiscussionofpolyvagaltheory