Porges developed the Polyvagal Theory, which explains how the autonomic nervous system (ANS) is involved in regulating visceral functions, social interaction, attachment, and emotions.
His research proposes that the ANS consists of two primary branches:
The sympathetic branch (related to alertness: sweating, flushing, tension, etc.)
The parasympathetic branch (promoting relaxation and calm)
These function like a car’s accelerator and brake. Porges’ key contribution is that the parasympathetic branch is further divided into two distinct pathways.
Through evolution, nature has developed three neural systems that regulate behavioral and physiological adaptation to:
Social situations
Threats
Life-threatening dangers
Activates visceral responses (e.g., increased heart rate, rapid breathing).
Triggers fight-or-flight reactions.
Supports social communication and safe immobilization (e.g., during intimacy or sleep).
Promotes physiological calm after sympathetic activation.
Linked to immobilization, dissociation, or collapse.
Activates in overwhelming threats or life-danger situations.
While adaptive for reptiles (e.g., oxygen conservation, thermoregulation), this response is highly traumatic for mammals.
Polyvagal Theory is transformative for therapy because it explains:
Why extreme stress/fear triggers body paralysis and traumatic dissociation (mental & somatic).
How a person’s sense of safety—whether a child with caregivers or a patient with their therapist—is foundational. Without safety, effective therapy cannot occur.
