This link goes to an interview with Dr. Stephen Porges about his polyvagal theory. This is a way of looking at the parasympathetic nervous system that helps to explain a lot about how people respond to traumatizing events or situations.
The old story was that we have two pathways in our involuntary nervous sytem, the sympathetic, or the arousing system, and the parasympathetic, or the calming system. The sympathetic was activated by a sabre-toothed tiger leaping at us (or someone stomping on the brakes ahead of us on the bridge) and we were inspired to fight or run away. The parasympathetic went into action in opposition, calming our bodies down when the tiger was gone or we had outrun him. Turns out that this “either-or” model probably doesn’t really describe how things actually happen in the nervous system. The model worked pretty well clinically; people who were stressed had over-active sympathetic systems and needed to do relaxation exercises to activate their calming system. When Herbert Benson labeled this the Relaxation Response in the 1960’s, it was a breakthrough and it still works pretty well when we are simply talking about external overstress and calming the body.
However, the realities of life in a body that has PTSD (post-traumatic stress disorder) were not really accounted for by this model. For example, people who have been traumatized will often experience hyper arousal and hyper-vigilance. That’s consistent with the opposition model. But on the other hand, PTSD victims will also often be numbed, hypo-aroused, emotionally empty or frozen. This can happen with or without being dissociated or depersonalized. The old model just cannot account for how a person could have TOO MUCH activity in the parasympathetic system.
So Porges’ polyvagal theory is hierarchical rather than simply oppositional. He posits that there are three distinct aspects to the vagus nerve, the tenth cranial nerve, and that these developed in the mammalian nervous system concurrently with our social and emotional behaviour. That is, the physiology of the nervous system develops as a cause and an effect of behaviour. The three parts are responsible for different aspects of functioning; communication, mobilization, and immobilization. Social connection requires visual and auditory attention and expression; this part of the system ennervates the face, mobilizing the mouth and eyes, making it possible to listen and to speak, and to make eye contact. The mobilization system makes fight or flight possible, while the immobilization system enables the organism to “play dead’ or to feign death or syncope to the degree that a potential aggressor will lose interest.
The most interesting (to me) part of this model is that the social interaction system is connected to our sympathetic nervous system. Look here at what Stephen Porges said in the interview when asked about how this works:
I’ve heard the human mind described as a paranoid instrument. The premise is that when we are living in our senses, in the here and now, we usually feel safe, but our thinking mind often throws scary impressions in front of us, as if it’s anticipating some threat.
SP: I’ll address that by describing to you a part of our nervous system that is entirely focused on responding to other people, even other mammals like dogs and cats. This is not the same part of the nervous system that can put us into states of enlightenment or ecstasy. In a sense, this is a very grounded component of our nervous system. It engages contact with certain levels of senses that are not the ones that you’re describing. It’s where we are feeling our bodily information from inside our organs. This information from the body actually travels through nerves up through the brain stem and radiates upward to our cortex. This part of the nervous system provides a contact with reality; it regulates our bodily state, so we become alert and engaged. That does not include all of human experience, but it does include most of what we call social interactions. We can say that the social interactions are a very important component of our psychological experience as human beings. And this system, the social engagement system, is what determines the quality of those interactions—the features that we show other people, the facial expression, the intonation of our voice, the head nods, even the hand movements, are part of this. And if I turn my head away while I’m talking to you, if I talk in a monotone without any intonation, or if I drop my eyes, will you have a visceral response? How do you feel when I do that?
RD: It feels like you’re not very present, like you’re withdrawing or you’re disconnected.
SP: Disconnected, which may be interpreted by the other person as evaluative, not liking, not being motivated to engage, condescending or suspicious. So these facial gestures, which for some people are purely physiological responses, are now interpreted with a moral or, at least, a motivational overlay. This may or may not be true. Social engagement is a unique and very powerful component of our interactions.
As a therapist, I am very interested in how to make “safety” for my clients. As a person, I am interested in how to help myself feel connected and comfortable in my world. When I can see a person looking away, unable or unwilling to connect socially, I can now think of this as a function of the autonomic nervous system, not just voluntary behaviour. If a person has a trauma history, then these elements of their social interaction may be a manifestation of their struggle….and imagine how it can keep on influencing relationships! Plus this model has a lot to tell us about how our awareness of our bodies influences our sense of safety and the ability to soften into our lives and connect with others.
Hmm, lots to ponder…..if you want more, I suggest http://www.wisebrain.org/Polyvagal_Theory.pdf