Polyvagal Theory, Scientific Dialogue, and the Integrative Path of Interpersonal Neurobiology

Polyvagal Theory, Scientific Dialogue, and the Integrative Path of Interpersonal Neurobiology

In recent months, two papers published in 2026 have generated renewed discussion about Polyvagal Theory. A large group of researchers led by Paul Grossman presented a critique arguing that several aspects of the theory are inconsistent with current findings in autonomic physiology and comparative neurobiology. In the same issue, Stephen Porges responded that the critique mischaracterizes key elements of the theory and therefore does not adequately address the framework he originally proposed.

Moments like this are not unusual in the history of science. In fact, they are often signs that a field is maturing. When ideas become influential, they naturally invite deeper scrutiny, refinement, and debate.

Polyvagal Theory has had an undeniable impact on how many clinicians and researchers think about the relationship between physiology, emotion, and social connection. It helped bring attention to the idea that the nervous system organizes patterns of regulation that shape how we move between states of safety, defense, and connection. For many practitioners working with trauma, attachment, and development, these ideas offered an accessible language for linking body and mind.

At the same time, neuroscience continues to evolve rapidly. Questions about the evolutionary narrative of vagal pathways, the interpretation of physiological measures such as respiratory sinus arrhythmia, and the specific functional organization of brainstem circuits remain active areas of investigation. As methods improve and data accumulate, some aspects of any theory may be revised or reframed. This is a normal and healthy process in science.

From the perspective of interpersonal neurobiology (IPNB), these conversations are best understood within a broader integrative framework. IPNB was founded on the principle that understanding the mind requires linking multiple levels of analysis: brain, body, relationships, and culture. Rather than reducing human experience to a single mechanism or pathway, the field seeks patterns of integration across systems.

Polyvagal Theory can be seen as one influential contribution within that larger landscape. Its emphasis on the biological foundations of social engagement resonates with the IPNB view that relationships are not separate from biology but are deeply embedded within it. At the same time, IPNB does not depend on any single explanatory model of autonomic regulation. Our understanding continues to evolve as neuroscience, developmental science, and systems theory expand.

What is most valuable in moments like this is the opportunity for deeper integration. Scientific dialogue invites us to clarify concepts, test assumptions, and refine the models that guide research and clinical practice. The goal is not to defend or dismiss a particular theory, but to allow our collective understanding to grow more precise and more comprehensive.

In this spirit, the current debate around Polyvagal Theory reflects the vitality of the field. The conversation encourages us to continue exploring how physiological regulation, relational experience, and the development of the mind are interconnected.

As interpersonal neurobiology continues to develop, the task remains the same as it has always been: to cultivate an integrative science of the mind that welcomes new evidence, honors useful insights, and remains open to revision as our understanding deepens.

Reference

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 Stephen W. Porges (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), 113–128. https://doi.org/10.36131/cnfioritieditore20260111

Siegel, D. J., & Drulis, C. (2023). An interpersonal neurobiology perspective on the mind and mental health: Personal, public, and planetary well-being. Annals of General Psychiatry, 22(1), Article 5. https://doi.org/10.1186/s12991-023-00434-5

Siegel, D. J. (2020). The developing mind: How relationships and the brain interact to shape who we are (3rd ed.). Guilford Press.