Porges: Yes, but there are two vagal systems. The root of the Polyvagal Theory is the recognition that in the absence of the ability to fight or flee, the body’s only effective defense is to immobilize and shut down. This can be observed as fainting or nausea, both features of an ancient vagal circuit that reptiles use for defense. However, unlike the uniquely mammalian vagal pathway, these vagal pathways are unmyelinated, and are only effective as a defense system when the newer circuits, including the sympathetic nervous system, are no longer available for interaction and defense. Our reptilian ancestor was similar to a turtle, and the primary defense for a turtle is to immobilize, inhibit breathing, and lower metabolic demands. Although immobilization may be effective for reptiles, it can be life-threatening for mammals, and for humans it can lead to states of dissociation. The Polyvagal Theory provides a way of seeing how the organization of our nervous system can shape our understanding of clinical disorders and issues, enabling us to see symptoms like dissociation not as bad behaviors, but as adaptive reactions to cues in the environment that trigger our physiological responses to perceived dangers.
Think about it this way. When you want to calm a person down, you smile and talk to them in a soothing way. The nervous system detects these cues and down-regulates or inhibits the sympathetic nervous system. But when the sympathetic nervous system is activated as a defense system, it turns off all those social-engagement behaviors. Clinicians are aware of that. But what they often don’t understand is the role of the vagal system in shutting down as a defensive strategy in response to a life threat. When someone is immobilized, held down, or abused, the vagal system is triggered, and they may disassociate or pass out—or perhaps drop dead or defecate. It’s an adaptive response.
I often talk about immobilization with fear and contrast it to immobilization without fear. The mouse in the jaws of a cat is immobilized with fear. The mouse isn’t voluntarily playing dead; it’s fainted. But someone in the embrace of a lover, parent, child, or friend is immobilized without fear.
RH: We might call that stillness, or peace.
Porges: Right, you’re still, but you’re being present. For reptiles and more primitive vertebrates, the primary defense system was to disappear—to immobilize, stop breathing, and look like you’re dead. For mammals, immobilization is a risky business. We have to be selective about whom we can feel still, calm, and comfortable with.
Many clients have difficulty feeling comfortable in the arms of another. They can’t immobilize without fear. If you go through their clinical histories, you’ll find that many were severely abused and had experiences of being forcedly held down. These experiences of forced immobilization trigger fear responses and shutting down. Those who survive these experiences don’t want to be immobilized and find it difficult to be held and calmed, even by people who are trying to be helpful. This response is often expressed as anxiety and a need to keep moving, which is a functional defense to a fear of immobilization. Often individuals with a history of immobilization with fear will adaptively become anxious and go into panic states to avoid this immobilization state. This is a problem many therapists see in their practices.
RH: What are the practical implications of Polyvagal Theory for clinical work?
Porges: It heightens our appreciation of the role of creating safety in therapy. For example, our bodies, physiologically, are extraordinarily sensitive to low-frequency sounds. We, like other mammals, interpret these low-frequency sounds as predatory. If your clinical office is bombarded with sounds from ventilation systems, elevators, or traffic sounds, your client’s physiology is going to be in this more hypervigilant defense mode. Likewise, if you sit some people in the middle of the room away from a wall, they may become hypervigilant and concerned with what’s going on behind them. If we’re not safe, we’re going to assume that neutral faces are angry faces. We’re going to assume the worst because that’s what our nervous system tells us to do. As vertebrates evolved into mammals, they had to interact with other mammals for survival. They needed to detect the social cues and identify when it was safe to be with another mammal. Thus, vocalizations in social contexts are less about syntax and language and more about the intonation conveying emotional state. Again, this is critical in therapy because the intonation of voice conveys more information about the physiology of the client than the syntax.
RH: In other words, how you’re saying something means more than what you’re saying.