The Link Between Polyvagal Theory and Trauma

Polyvagal theory explains our responses to certain traumatic events. Find out more here.

Written and verified by the psychologist Gorka Jiménez Pajares.

Last update: 05 September, 2023

Stephen Porges claims that the polyvagal theory and trauma are indivisible. His theory gives an explanation of how our bodies react to traumatic events. It emphasizes that the nervous system has more than one defense strategy against danger, not only the classic fight/flight strategy. In fact, it claims that, without being aware of it, our brains are constantly evaluating risks in the environment, minute after minute, day after day.

For some people, it’s the physical characteristics of what they see, hear, or smell that trigger fight/flight behavior. Others may not respond to the stimulus in the same way. Thus, the crucial factor isn’t the traumatic event, it’s the individual’s response to it.

Trauma from the polyvagal theory perspective

The polyvagal theory tries to explain how our autonomic nervous system (ANS), the way we regulate and express emotions, and the way we behave socially are related and mutually influence each other. It identifies three levels or hierarchical systems:

• First level. It contains the biologically oldest defense system, the immobilization response. The dorsal motor nucleus of the brainstem controls this level. It’s found in animals with a less evolved nervous system, such as reptiles.
• Second level. It contains a somewhat more refined defense system: fight or flight. The sympathetic nervous system controls this level. It originally appeared in mammals.
• Third level. It contains the most sophisticated system: the response or social hook. This system is responsible for cooperative interpersonal behavior. The nucleus ambiguus of the brainstem controls this level. It’s a recent structure in evolutionary terms. It’s highly developed in higher primates and humans.

What’s traumatic for some isn’t for others

For some individuals, what others would consider a traumatic event is just one more situation. However, for others, it’s a threatening event that directly endangers their lives. Therefore, they activate responses in their body to deal with it. In fact, they respond as if they were going to die.

Currently, it’s unknown how our circuits decide which situations are safe or not. We might conclude that, in the face of threats from our environment, if we’re protected with the third level, the newest level, we do well.

For example, in the face of an experience of sexual abuse, the oldest vagal circuit would be activated: immobilization. We don’t have conscious control of this circuit and can ‘tune out’ or pass out.

In therapy, people who talk about abuse, especially sexual abuse, often experience the feeling of having been physically subdued. They usually describe feeling as if they weren’t really there at the time. In reality, they passed out or dissociated themselves from the experience.

Neuroception: a key concept of polyvagal theory in relation to trauma

Neuroception is detection without awareness. While perception requires awareness of what’s being perceived, neuroception doesn’t. It means detecting something without us being aware of it. Our brain levels monitor, evaluate, and detect the degree of threat that each of the elements we perceive might pose to us. Neuroception highlights the third system: that of engagement or social cooperation.

The work of the third system can influence our more primitive defenses. However, when the risk increases, the first two systems take over. Indeed, in response to potential or actual danger, the first and second systems trigger a cascade of metabolic, hormonal, and neural reactions so that we can either fight or take flight.

The same traumatic event can trigger different neuroceptive reactions. We know that traumatic events produce dissociation. To dissociate is to separate or break something. Often, the account of the traumatic event and the sensory characteristics are separated. For example, acoustic signals, smells, colors, and tastes.

Today, we know that one of the most powerful triggers of neuroception (unconscious detection) is acoustic characteristics.

The listening project

The listening project is an intervention project. It investigates whether training the muscles of the middle ear can help people who’ve suffered trauma.

The polyvagal theory supports the hypothesis that, if we start tapping into our third system, the social cooperation system, and train the muscles of the middle ear – important for detecting acoustic features – we’ll be more adept at distinguishing the human voice from the rest of the stimuli. This will help the individual to be more spontaneously social.

The goal is to create auditory hypersensitivity. The idea is that by increasing our sensitivity to human voices, we become more sociable. In effect, our third response system is activated more. This makes the possibility of experiencing an event as traumatic more unlikely.

Adaptability

As a rule, as human beings, we’re extremely adaptable to the circumstances in which we find ourselves immersed. For instance, if we come from a family where our parents were depressed or chaotic, we adapt not to get involved. We downregulate or turn off our third system: that of social cooperation.

This theory could also shed more light on certain psychiatric diseases and disorders that are related to failures in the regulation of the three systems. For example, trauma, dissociative identity disorder, and borderline personality disorder.