Stephen W. Porges, PhD Photo Courtesy of Indiana University

Early humans stalked by brutal killers had a limited choice: Gird for battle or run to safety — as in “fight-or-flight.” A bit further down the evolutionary road, we added “tend and befriend” to our danger response repertoire, which may have allowed particularly the females among us to protect children and cultivate a social group for mutual defense and support.

And that was that — until Stephen Porges, PhD, the Distinguished University Scientist at Indiana University in Bloomington, introduced a third option: freeze or faint.

His widely-cited polyvagal theory contends that living creatures facing or sensing mortal danger will immobilize, even “play dead,” as a last resort. This strategy occurs instinctively — without conscious thought and at the behest of a nervous system quickly deciding whether the environment is dangerous or safe. It can be quite confusing to 21st century humans who find themselves triggered into immobility by, for example, a nasty boss, combative spouse, or alcoholic parent, rather than a raging tiger. Baffled by feelings of disengagement, dissociation, depression, and numbness, we may diagnose other causes — and adopt inappropriate solutions.

The only cure, Dr. Porges says, is to send signals of soothing safeness that bypass the conscious to reach the most inaccessible part of the brain, reassuring it that the environment is, in fact, safe. For Porges, the best vehicle to reach that destination is music. Music therapy provides a key that can unlock the numbed, deeply embedded ancient brain, allowing an individual to engage and interact with people, experiencing results that can be breathtaking.

Porges shared his theory, his therapy, and his respect for the body’s longest nerve, with Everyday Health.

Everyday Health: How would you describe yourself and your work?

Stephen Porges: I’m a neuroscientist working at the intersection of behavioral neuroscience, clinical issues, and bioengineering. As a “deconstructor” of complex biobehavioral systems involved in human behavior and health, I try to decipher, explain, and disseminate knowledge about the nervous system’s innate abilities to create and maintain feelings of protection, support, and social connectedness.

I developed the polyvagal theory in 1994 to explain how humans, in seeking safety and survival, monitor and mediate their reactions to the world. To describe how the nervous system — and I focus on the vagus nerve — decides whether the environment is dangerous or safe, I developed a novel concept that I labeled “neuroception.”

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While perception implies a conscious effort to detect risk through sensory input, neuroception optimizes survival by circumventing those sluggish cognitive processes, so that we can rapidly detect danger. When risk or danger cues are detected, the body cascades protective biobehavioral reactions that we frequently and simplistically call “stress.” Meanwhile, safety cues — such as the melodic voice of a mother calming her infant or singing a lullaby — elicit biobehavioral responses that support health, growth, and mental and physical healing.

EH: Focusing on the biobehavioral reactions to detecting risk or danger, do you mean the fight-or-flight response?

SP: Not just fight-or-flight. Our protective defense reactions can lead to behavioral strategies that also include immobilization. When threatened, we might reflexively lose the capacity to mobilize our bodies for fight-or-flight and instead shut down. It causes a total loss of motor tone, as when mammals reflexively pass out and feign death to avoid a predator. In other situations, the immobilization defense might seem like an inability to voluntarily move. Imagine Edvard Munch’s painting The Scream, where the central figure produces no sound when trying to scream.

EH: What about our biobehavioral reactions to detecting safety — that is no risk, no danger?

SP: If our neuroception detects that a person, situation, or environment is low or no risk, calming responses damp down the defensive reactions we associate with chronic stress. That’s why having access to calming cues — soothing voices, therapeutic music, facial expressions that are friendly and reassuring, social engagement of some kind — enable us to buffer the disruptions and damage of stress and enhance our resilience to daily challenges.

We may reflexively mobilize, but absent any fear or danger factor, we can use that energy to play, not fight. We may reflexively immobilize, but without the fear or danger factor we can feel safe lying still in the arms of a loved one, for example, or awaiting the helping hands of a friend. Those interactions promote social engagement, not dissociation and disconnectedness.

EH: How does all this relate to our understanding of chronic or acute stress?

SP: I view these biobehavioral responses, driven by neuroception, as missing links in understanding why and how specific events stress out some people and not others.

Since I developed the theory, I’ve expanded it to apply to trauma, autism, and other mental disorders whose common stress-related core involves our ability to connect and feel safe with others.

EH: How does the polyvagal theory account for what we call stress?

SP: I don’t like the word “stress,” because it’s treated as a negative experience, despite the fact that some neurophysiological responses are adaptive and support normal or everyday biologically appropriate behaviors. For example, you can mimic many of the neurophysiological characteristics of stress by shifting your posture or walking up a staircase. Waking up in the morning is another example of an action that, internally, has the hallmarks of stress. In all these situations, your body’s physiological changes are doing what they’re supposed to do — supporting the metabolic demands of performing those actions.

Polyvagal theory encourages us to go beyond the physiological shifts alone to consider them in context. This means determining whether some physiological reactions are the direct consequences of movement, and whether the adaptive function of the movement is for defense, such as fight-or-flight behaviors, or prosocial interactions, such as play, or even self-calming strategies, such as exercising or listening to and making music.

The theory also enables us to consider a second defense system. Unlike the metabolically costly fight-or-flight mobilization, which diverts many bodily systems to confront danger or escape, this second defense system is metabolically conservative. It reduces physiological demands by putting the body into a freeze or “play dead” mode, one we share with many other mammals (for example, a mouse in the jaws of a cat).

In this state — which is, again, brought on without conscious thought — an individual may lose awareness or even consciousness, become numb, and dissociate.

Just as movement or mobilization can be positive when used for social interactions like play and dance, immobilization also has prosocial potential. In situations deemed safe (yes, through neuroception), immobilization can foster intimacy and trust. When we feel totally safe in the arms of another, the nervous system optimizes the neural pathways necessary for health, growth, and physical and mental healing.

EH: You mentioned earlier that you see all these reactions and the behaviors they engender — social interaction, mobilization, and immobilization — as an adaptive part of human evolution, is that right?

SP: Yes. The cues that elicit these different reactions are embedded in the evolution of the vertebrate autonomic nervous system. Through evolution, a hierarchy emerged where the autonomic nervous system’s adaptive biobehavioral circuits optimized survival through trust as well as through the defensive strategies of fight-or-flight and feigning death.

The body is amazingly efficient at assessing risks and responding with defensive strategies that can be effective for some kinds of peril. But it pays a price for maintaining these defenses too long by creating chronic stress. One of the reasons chronic stress is so toxic is that it both diverts the body’s resources to support an ongoing danger-defense response and, by essentially hijacking the autonomic nervous system, it reduces our capacity to regulate the health-producing physiological states that depend on the autonomic nervous system.

We can’t handle life’s challenges until we recruit and reset the nervous system for optimized function. And we can’t do that until we fully understand the body’s ancient and more recent evolutionary responses to peril.

Understanding those responses begins with recognizing that we categorize events not as stressful or relaxing, but as threatening or safe. The three neural circuits that regulate the autonomic nervous system, which evolved sequentially, are organized from the most ancient to the newest. Together, they serve as a road map of the sequence neuroception takes in assessing threats and safety.

EH: What are these three circuits?

SP: To begin with they are integral to the vagus, the longest of the nerves originating in the brain. The vagus — the name is a Greek word for "wandering" — meanders through the body communicating sensory and motor impulses to our organs. It’s the vagus that, for example, is involved in controlling breathing and heart rate, both of which occur unconsciously.

Now, the newest of the three neural circuits, the ventral vagal complex (named for that part of the brain stem), is unique to mammals. It evolved to soothe and socially calm the animal. This circuit, or pathway, is coated with fatty myelin, which speeds and sharpens communications between the brain stem and the structures regulating the face and head muscles.

Adaptively, we see this pathway working when the infant mammal depends on maternal caregiving. The pathways that sooth the newborn (for example, sucking, vocalizing, and listening) become the means for us to connect and to trust as we mature. The coordination of sucking, swallowing, and breathing transform during our development into a proactive and responsive social engagement system. This system also coordinates with the pathways that regulate and integrate breathing and heart rate with facial muscles that control expression, ingestion, and listening.

The second circuit evolved to support the resources needed to mobilize. That’s where we find the autonomic flight-or-fight features we’ve historically associated with chronic stress. These systems flood the body with adrenaline when immediate action is required, raising the levels of cortisol when prolonged movement, such as fighting or running, is needed.

The third and oldest circuit, a relic of our ancient ancestors, shuts down metabolic demands in life-threating situations. Since this involuntary reflex slows the heart, it can cause a terrified person to faint, or it can completely immobilize the person who suddenly freezes or “plays dead.” Or it can cause a loss of awareness and bodily feelings.

The evolutionary purpose of freezing or fainting was to help guard against severe injury or death, as long as it didn’t result in organ damage from oxygen deprivation. For humans, there are different positive and negative consequences. It may help protect us from lethal injury, but the nervous system — once triggered — doesn’t easily transition out of a freeze or faint state. And remaining in that vigilant state increases our vulnerability to conditions like irritable bowel syndrome, fibromyalgia, blood pressure instability, and migraine.

There’s another downside, too. Because humans seek to explain our reactions, we use words to describe our emotions (such as anger or fear) or our affective state (anxiety or stress, for example) without knowing the context of primitive automatic defenses that are in play. And when we misinterpret our unconscious physiological reactions and assume they were caused by the intentions of another, we remove the opportunity to be calmed by that person. We can feel withdrawn and disconnected from the outside world long after the source of danger vanishes.

EH: That’s what you believe is happening in those people you mentioned who have been abused or faced extreme danger and experience continuing dissociation, a feeling of detachment from reality?

SP: Yes, I believe that when faced with a life threat, the nervous system may “retune” and bias neuroception towards detecting danger cues, even when the cues are actually neutral.

I also believe this defensive bias can be modified through informed use of safety cues, which is where music therapy may be useful. When neuroception perceives cues of safety through specially modulated vocal music, it creates a situation that allows for intimacy, playfulness, and pleasure.

EH: How does music therapy — or, perhaps more accurately, therapeutic music — provide safety, and calming cues?

SP: Music therapy bypasses the conscious, directly accessing the preconscious brain areas we share with other mammals; regions that instinctively evaluate and react to risk or safety.

The earliest suggestions of safety are the vocalizations of “mother-ese”; the modulated, high-pitched sounds parents adopt when communicating with an infant. Infants are instinctively programmed to learn intentionality through intonation. It’s not what the parent says, but how he or she says it.

Music therapy attempts to mimic this. By using specially engineered music and adopting a meter or timing suggestive of the human heartbeat, it conveys a sense of safety. Or, through a recreation of “mother-ese,” it communicates comfort, soothing, calmness, and safety and dampens flight-or-fight mobilization, increasing the parasympathetic nervous system responsiveness. We start with music that emphasizes the mother engaging her infant and then process it through algorithms that further modulate the frequency.

When I first used this filtered music with autistic children who couldn’t previously engage, many suddenly and spontaneously turned, looked, articulated, and interacted in socially appropriate ways. The music had fired up previously dormant neural circuits for self-regulation and social connection. Previously trapped in a chronic flight-or-fight state, these children began to let people into their world. Whether they were dealing with chronic stress or post-traumatic stress disorder (PTSD) or autism, patients became more receptive to spontaneous social engagement and began to return to health, growth, and restoration.

I’ve seen lives changed after actively listening to vocal music altered to amplify the cues of safety. Drugs and medication and dietary changes can’t and don’t accomplish the same result.

This process, of modulating and applying vocal intonations in a clinical setting, was awarded a United States patent that also covers technology that acts as an acoustic vagal nerve stimulator, calming the body and increasing the vagal influence on the heart. The patent has been licensed by Integrated Listening System, which markets a program of computer-altered vocal music to therapists called the Safe and Sound Protocol.

EH: How do you transform that revelation regarding the acoustic features of vocal music into actual treatment?

SP: The initial treatments focused on autism spectrum children with hypersensitivities to sound or difficulties in auditory processing. Clients spent one hour a day for five days listening to the music. We found improvements in social communication and auditory processing, and reduced auditory hypersensitivities.

Recently, therapists began testing it with trauma survivors, and found it accelerates therapeutic progress. There are several clinical trials evaluating the Safe and Sound Protocol for autism, Prader Willi syndrome, chronic pain, and attention deficits. Therapists have found it effective in diminishing symptoms of PTSD and anxiety, for example, when they retune the nervous system for acceptance and trust rather than defensiveness.

EH: How can this advance help people cope with chronic stress?

SP: When we understand how the nervous system encodes previous violations of trust, we realize that some behaviors are simply physiological reactions to prevent us from shutting down. That knowledge makes us better able to accept unexplainable behaviors as automatic, unconscious responses.

I believe it also may make us more aware of our interpretations of things around us; the way our instinctive reactions change the stories we tell ourselves to explain and justify our feelings and behaviors. There’s never been a greater need for this awareness. As our relationships move further away from the cues of safety — the sound of a soothing voice or the sight of an expressive, expansive face — we’re less secure. It happens physiologically.

Polyvagal theory’s explanation of the evolutionary origin of the neural circuits can help us better understand the price we pay for minimizing our nervous system’s mandate to trust and to be “safe” in proximity with others. Violating this mandate can disrupt the homeostatic function of our autonomic nervous system and undermine our mental and physical health, contributing to the disorders we associate with chronic stress.

EH: What hope can you offer us, via the polyvagal theory, that the increasing incidence of dissociation and depression can be overcome?

SP: First, a neurophysiological understanding of dissociation and depression — and the cascade of effects that trigger body numbness, loss of time-sense, and a diminished ability to interact and connect — trains us to reinterpret our reactions as valiant attempts to survive, rather than failures to adapt to tough situations.

Second, we can forgive ourselves for certain behaviors when we’re dealing with reflexive reactions. You can’t think yourself or talk yourself out of an automatic reaction. You have to reach into your personal resources, accept your defensive response, and seek cues of safety and trust.

We also need to find more opportunities to exercise the social engagement system’s neural circuits by using warm, inviting facial expressions; by producing and listening to melodic voices like a mother’s lullaby; and by seeking direct face-to-face interactions in real time through collaborative play, dancing, or other activities.

We don’t need proximity and face-to-face interactions all the time, but we do need a daily dose. Without it, our body shifts to a physiological state where we support defensive strategies not prosocial ones. And that sacrifices not only our mental health, but also our physical health. That doesn’t have to happen if we listen to our body and respect its needs.