Polyvagal theory is a theory of emotional regulation and social behavior that was developed by Stephen Porges, a neuroscientist. The theory suggests that the human autonomic nervous system (ANS) has evolved in three stages, each with its own set of adaptive responses to threat and safety.
The theory describes two branches of the ANS, the sympathetic nervous system (SNS) and the parasympathetic nervous system (PNS), and a third system, the ventral vagal complex, which regulates social engagement and emotional expression.
- The sympathetic nervous system (SNS) is activated in response to perceived threat, it increases heart rate, blood pressure and glucose levels, preparing the body for a fight or flight response.
- The parasympathetic nervous system (PNS) is activated when the body is in a safe environment, it regulates digestion, rest, and repair.
- The ventral vagal complex is activated in social engagement, it allows for the expression of emotions, such as joy, and the ability to connect with others.
According to polyvagal theory, when the body experiences threat, the ventral vagal complex is deactivated, and the SNS or PNS takes over. When the body is in a safe environment, the ventral vagal complex is activated, and emotional expression, social engagement and connection are possible.
Polyvagal theory suggests that individuals with certain mental health conditions, such as PTSD or borderline personality disorder, may have difficulty in regulating their autonomic nervous system, which can lead to emotional dysregulation and difficulties in social interactions.
Therapies that aim to activate the ventral vagal complex, such as yoga, mindfulness, and other somatic therapies, can be beneficial for those individuals to improve emotional regulation and social interactions.