The vagus nerve between image and mechanism: Why the polyvagal theory can provide guidance in trauma, even though it has been refuted by scientific criticism

Introduction to the series

The regulation of our autonomic nervous system is at the centre of many modern health debates – but there is often a huge gap between viral biohacks and sound science. This new blog series is dedicated to closing that gap. Step by step, chapter by chapter, we will show you how the nervous system, self-regulation and neuromodulation really work together – based on evidence-based research, not marketing promises.

These articles pave the way for a larger project to be published at the end of the year: a practical guide for people with post-viral syndromes, chronic fatigue, attention problems or psychosomatic complaints – and for anyone who wants to learn to trust their nervous system.

What it's about:

Each article in this series focuses on a chapter of the upcoming book. We shed light on the basics of the autonomic nervous system, debunk common myths, present scientifically proven methods for neuromodulation, and show how to implement practical strategies in everyday life. Whether you are new to the topic or already have experience with topics such as vagus nerve stimulation, HRV measurement or polyvagal theory, this series offers guidance, clarification and concrete steps for action.

The following chapters await you:

1. Changing the nervous system? A critical introduction to the topic of self-regulation.

2. How your nervous system really works.

3. Why many theories are more hypothesis than help.

4. What scientifically validated neuromodulation can achieve today.

5. Misconceptions about HRV, the vagus nerve and biohacking revealed.

6. Practical strategies for better regulation in everyday life.

7. How to develop your own individual self-regulation concept.

Future special chapters:

• The science of neuromodulation – A deeper insight into taVNS and related methods. • Exercise as therapy – How targeted training strengthens the brain.

• Syndrome-specific strategies – Long COVID, ADHD, CPTSD, chronic pain & cognitive decline.

Stay tuned – because knowledge is the best foundation for trust in your own body. And trust is the first step towards healing.

Why many theories are more hypothesis than help.

Many people breathe a sigh of relief when they first hear terms such as ‘dorsal shutdown’, ‘ventral vagus’ or ‘social engagement system’. Finally, there seems to be a language for experiences that previously felt chaotic or shameful. The so-called polyvagal theory offers a memorable explanation of how our nervous system responds to stress, connection or danger. But as helpful as this theory may be, it is not a diagnosis, proof or a mechanical law. And it does not replace a deeper understanding of complex physical and psychological relationships.

In this article, we show why popular models such as polyvagal theory provide important guidance, where they are empirically questionable, and how they can be used without being taken over by them.

Criticism of polyvagal theory: What is the hype about the vagus nerve?

The so-called polyvagal theory is very popular in therapy, coaching and social media. It promises to explain many psychological states – from trauma to anxiety to dissociation – through a new view of the autonomic nervous system. But what can this model really achieve? What is scientifically sound – and what is more hypothesis than help? This article questions central assumptions of Stephen Porges' polyvagal theory and highlights why its popularity should be critically reflected upon.

What does Stephen Porges' polyvagal theory actually say?

The polyvagal theory, developed by Stephen Porges, aims to re-explain the regulation of the autonomic nervous system. Instead of a binary model (sympathetic vs. parasympathetic), it proposes a hierarchically ordered structure:

• According to Porges, the ventral vagal branch stands for social security, connection and regulation.

• The sympathetic branch reacts with flight or fight mechanisms.

• The dorsal vagal branch is responsible for breakdown, dissociation or collapse.

This theory is often used to explain symptoms such as panic, trauma or emotional shutdown – so it promises a comprehensive, psychologically and physiologically integrated model.

Who is Stephen Porges – and how did his polyvagal theory come about?

Stephen Porges is a psychologist and neuroscientist. His work is based on heart rate analysis and the role of the vagal system. He published the first version of his polyvagal theory in 1994. His central thesis is that the vagus nerve evolved phylogenetically in mammals and enables social communication. Porges bases this on the assumption that a new branch of the vagus – the ventral branch from the nucleus ambiguus – developed exclusively in mammals and is responsible for social engagement.

What role does the vagus nerve play in polyvagal theory?

The vagus nerve is the tenth cranial nerve and part of the parasympathetic nervous system. Among other things, it controls heart rate, digestion, facial muscles and other homeostatic functions of health. According to Porges, the ventral vagal branchis directly connected to the striated muscles of the face, the middle ear and the nucleus ambiguus – and thus forms the basis for social interaction. But here we already encounter a problem: the connections between the anatomical structures are controversial, in some cases not measurable, and many assumptions of the polyvagal theory are not empirically proven.

What is the actual anatomical structure of the mammalian autonomic nervous system?

The autonomic nervous system involuntarily regulates vital functions – from heart rhythm to breathing. In mammals, there are three main axes:

• The sympathetic nervous system (activation, defensive response)

• The parasympathetic nervous system (rest, vagal regulation)

• The enteric nervous system

The polyvagal theory claims that the mammalian autonomic nervous system has changed evolutionarily and that the ventral vagus nerve has a social function. However, anatomical studies show that the evolutionary development of the vagal system is not clearly divided into three parts – many functions are functionally redundant and not linearly hierarchical.

Which assumptions of the polyvagal theory are problematic?

It is functionally understandable that social closeness can regulate the nervous system. However, many of the structural statements – for example, on the role of the motor nucleus of the vagus, the nucleus ambiguus, or the exclusive role of the ventral vagal pathway – are not clearly proven anatomically. Terms such as ‘ventral state’ or ‘dorsal shutdown’ also sound precise, but are not directly measurable – neither through imaging nor heart rate analysis. The assumption that a simple slowing of the heart rate is specifically attributable to a ventral state was critically questioned in 2021 by Paul Grossman.

What do researchers such as Paul Grossman criticise about the theory?

Paul Grossman, a clinical researcher in psychophysiology, is one of the most prominent critics of polyvagal theory. In several publications, he has described the theory as ‘largely disproved’, at least in its core anatomical and functional claims. According to Grossman, the physiological reality is more complex than the theory suggests. In addition, terms such as ‘social engagement’ or ‘ventral vagal activity’ are therapeutically exaggerated – even though they are not operationalised in scientific studies.

How plausible is the concept of neuroception?

A central concept in polyvagal theory is neuroception – an unconscious scan of the body for safety or danger. But here, too, the problem becomes apparent: there are no clear physiological correlates, no imaging techniques, no HRV data that unequivocally prove the existence of ‘neuroception’. The concept remains a metaphorical assumptionthat is clinically difficult to use.

Why is the theory being hyped?

Many therapy and coaching services today work with statements such as:

• ‘You must first enter the ventral state in order to heal.’

• ‘Dorsal shutdown prevents your social interaction.’

• ‘Regulation begins with the activation of the ventral system.’

The problem: These statements claim to describe objectively measurable states, but are often based on symbolic models. This can lead to blame among clients whose symptoms do not improve: ‘You are blocking your healing.’

What alternatives are there for regulating the autonomic nervous system?

Instead of relying on a single model, a comparative approach is worthwhile. Evidence-based approaches include:

• HRV biofeedback to promote vagal flexibility

• Breathing training with a focus on slow exhalation

• Exercise with a rhythmic component

• Clinically validated neuromodulation such as taVNS

• Therapeutically accompanied bodywork

These methods are not based on myths, but on what is scientifically proven to support the autonomic nervous system of mammals.

Important takeaways

• The polyvagal theory is a fascinating model – but not proof.

• Many of its assumptions are anatomically, functionally and psychologically controversial.

• The theory provides helpful metaphors, but it is no substitute for physiological diagnostics.

• Statements about ‘ventral states’ or ‘neuroception’ are not measurable.

• Therapy needs models – but not ideologies.

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When theories become new ideologies

As powerful as the language of polyvagal theory is, it can also be limiting. Namely, when it becomes a closed system of explanation:

• ‘I am not regulated, so I am not in a ventral state.’

• My anxiety shows that I unconsciously perceive danger.

• ‘This exercise doesn't work for me, so I'm blocking healing.’

The problem with this is that it creates shame instead of context. The complex reality of sleep deprivation, inflammation, hormonal changes, post-viral stress or psychosocial stress is reduced to a state model.

What helps: model pluralism instead of monoculture

One theory can explain. Multiple models can open up new possibilities.

• The polyvagal theory offers a narrative for social security.

• The concept of allostasis explains how chronic stress exhausts physiological systems.

• Neuroimmunology describes how inflammation influences mood and thinking.

• Cognitive neuroscience sheds light on attention, memory and self-perception.

A pluralistic approach allows symptoms to be understood not only as a condition, but also as a signal. And that is precisely what working with the autonomic nervous system is all about: orientation, not labelling.

Conclusion: Distinguishing between relief and simplification

The polyvagal theory has achieved a lot. It has helped people to view themselves with more compassion. But it remains a model. And models are tools – not truths.

Use this language when it serves you. Set it aside when it limits you. And always ask yourself:

Does this theory help me see myself more clearly – or does it blind me to other explanations?

In the next article: Which neuromodulatory methods are truly evidence-based – and how can they be used safely?

FAQ – Frequently asked questions about criticism of polyvagal theory

What is polyvagal theory and who developed it?

The polyvagal theory was developed in the 1990s by American psychologist and neuroscientist Stephen Porges. It describes three states of the autonomic nervous system that are organised hierarchically: social safety (ventral vagal), mobilisation (sympathetic) and shutdown (dorsal vagal).

What are the central tenets of the polyvagal theory?

According to Porges, the vagus nerve is not only a biological mechanism, but also central to our social behaviour. The ventral vagus enables emotional closeness and social interaction, while the dorsal vagus leads to withdrawal, collapse or dissociation when we are overwhelmed.

What is controversial about the polyvagal theory?

Critics complain that many of the assumptions – such as the anatomical separation between the ventral and dorsal vagus – have not yet been empirically proven. Terms such as ‘neuroception’ and ‘ventral state’ are also not scientifically operationalised and are more metaphorical in nature.

What are the disadvantages of polyvagal theory?

The theory tempts people to simplify complex symptoms. In practice, this can lead to problematic attributions such as: ‘You are not yet regulated’ or ‘You are in shutdown and blocking your healing.’ This often reinforces feelings of shame instead of contributing to genuine regulation.

Is polyvagal therapy effective?

There is no clinically validated ‘polyvagal therapy.’ Elements of the theory are used in various therapeutic schools, such as somatic coaching and trauma therapy. However, its effectiveness depends heavily on how thoughtfully the underlying model is used.

Is there evidence for the central premises of polyvagal theory?

In 2021, researcher Paul Grossman criticised that even after 20 years, there is no direct evidence for the three central premises of Porges – in particular for the physiological separation of the vagal branches as presented in the theory.

How should the functional anatomy of the vagus nerve be assessed?

Classical neuroanatomy shows that the vagus nerve performs numerous functions in the body, including heart rate regulation, digestion and voice production. However, there is no evidence of a clear division into ventral and dorsal branches.

What about phenomena such as ‘vagus tapping’ or ‘tapping as the key to resolution’?

Many of these methods do not originate from evidence-based medicine, but from self-help or wellness culture. For example, there is no evidence that vagus tapping leads to immediate activation of the parasympathetic nervous system. The effect could be more attributable to movement, attention or breathing – not specifically to the vagus.

What is the significance of movement in comparison to polyvagal theory?

Exercise strongly influences the autonomic nervous system – by activating the sympathetic nervous system, but also through the subsequent vagal rest. Many physiological effects attributed to the vagus could also be explained by metabolic processes – e.g. a natural slowing of the heart rate after exercise.

What does ‘Polyvagal Academy’ mean – science or wellness?

With the increasing success of the theory, an entire ecosystem has emerged: online courses, certifications, books (e.g. Carl-Auer Verlag), apps, breathing exercises and even electrical stimulation of the vagus nerve. Although these formats often aim to provide sound further training, it remains difficult to draw a line between evidence-based practice and esoteric wellness. Transcutaneous vagus nerve stimulation (taVNS) is often linked to the theory, even though its effects have been researched independently of Porges' model.