The nervous system asks one question
Polyvagal Theory (PVT), introduced by Stephen W. Porges in 1994, reframes the autonomic nervous system as the neural platform on which social behavior and psychological experience are built. The system is always asking a single question ~ Am I safe? ~ and it answers not with thoughts but with the body.
The three autonomic states
Recruited in reverse evolutionary order under threat: ventral first, then sympathetic, then dorsal. Open each state for its physiology, felt experience, and clinical note.
The newest branch, unique to mammals. When it is dominant we feel safe, connected, and capable of social engagement. The myelinated 'smart vagus' acts as a vagal brake ~ modulating heart rate without recruiting the sympathetic system, supporting prosody, facial expression, and attunement.
- Myelinated vagus nerve (cranial nerve X) ~ the 'smart vagus'
- Innervates muscles of the face, middle ear, larynx, pharynx
- Regulates heart rate via the vagal brake
- Supports vocal intonation, facial expression, and listening
- Feeling safe, calm, and present
- Capacity for curiosity, play, and intimacy
- Able to think clearly and make decisions
- Connected to self and others
Clinical note: This is the state we help clients access and sustain ~ not being calm all the time, but having the flexibility to move through states and return to ventral regulation. Porges calls it the neural platform for social engagement.
Match the intervention to the state
Release breathing and long out-breaths calm sympathetic mobilization ~ but in dorsal vagal shutdown they deepen the collapse. For shutdown, use gentle activation and co-regulation, not down-regulation.
Core principles
Safety is not the removal of threat. Safety is a neuroception ~ an unconscious detection of features in the environment that signal the absence of danger and the presence of connection.
Session language
How to assess state, deliver cues of safety, name what's happening, and work with shutdown.
- Right now, as you sit here, what do you notice in your body?
- On a scale from 'completely shut down' to 'completely wired,' where would you put yourself right now?
- Do you feel more revved up, or more collapsed? Or somewhere in between?
- What does your body want to do right now ~ move, freeze, reach out, pull away?
- I'm right here. You're not alone with this.
- Take a moment to look around the room. Notice what you see.
- Can you hear my voice? Just let the sound of it land.
- There's no rush. We have time.
- It sounds like your system is in protection mode right now ~ that makes sense given what you've been through.
- That shutdown feeling? That's your dorsal vagal system doing its job. It's not weakness ~ it's survival.
- The racing heart and tight chest ~ your body is mobilizing to protect you. It learned to do that for good reason.
- Right now you seem more settled, more present. Your social engagement system is coming online.
- I notice you've gone quiet and still. Can you feel your feet on the floor?
- Let's not try to push through this. Your system needs gentleness right now.
- Can you wiggle your toes? Just a tiny movement to let your body know you're still here.
- I'm going to keep talking softly. You don't need to respond. Just let my voice be a tether.
A note on the scientific debate
Polyvagal Theory has been enormously influential in clinical practice, and its core metaphors ~ the autonomic hierarchy, neuroception, co-regulation ~ have given clinicians and clients a shared language for understanding trauma responses. At the same time, some of PVT's specific neuroanatomical claims have been challenged by comparative physiologists and neuroscientists.
A 2023 paper by Grossman and colleagues questioned whether the phylogenetic hierarchy is supported by comparative anatomy, and whether the myelinated/unmyelinated vagal distinction maps as cleanly onto mammalian evolution as originally proposed. Porges has responded to these critiques in subsequent publications (2025), arguing that the theory has been mischaracterized and that its core predictions remain supported. The exchange has continued: in early 2026, Grossman and an international group of researchers published a multi-author evaluation in Clinical Neuropsychiatry arguing the theory is untenable, and Porges replied in the same issue.
This is how science works. The clinical utility of PVT's framework ~ helping clients understand their nervous system responses as adaptive rather than pathological ~ is not diminished by ongoing refinement of its neuroanatomical claims. What matters for the clinician is whether the framework helps you help your clients. For most trauma therapists, the answer remains yes.
References
- Porges, S. W. (2011). The Polyvagal Theory: Neurophysiological Foundations of Emotions, Attachment, Communication, and Self-Regulation. Norton.
- Porges, S. W., & Dana, D. (Eds.). (2018). Clinical Applications of the Polyvagal Theory: The Emergence of Polyvagal-Informed Therapies. Norton.
- Dana, D. (2018). The Polyvagal Theory in Therapy: Engaging the Rhythm of Regulation. Norton.
- Dana, D. (2020). Polyvagal Exercises for Safety and Connection: 50 Client-Centered Practices. Norton.
- Porges, S. W. (2022). Polyvagal Theory: A science of safety. Frontiers in Integrative Neuroscience, 16, 871227.
- Grossman, P. (2023). Fundamental challenges and likely refutations of the five basic premises of the polyvagal theory. Biological Psychology, 180, 108589.
- Porges, S. W. (2025). Polyvagal theory: A journey from physiological observation to clinical application. Frontiers in Behavioral Neuroscience, 19, 1593935.
- Grossman, P., et al. (2026). Why the polyvagal theory is untenable. Clinical Neuropsychiatry, 23(1).
- 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).
This material is covered in The EMDR Deconstructed Workbook, Chapter 3: Foundations. See the workbook page.