According to the Polyvagal Theory, when a person is feeling safe—not threatened or in danger—and if her body is healthy and functioning well, she can enjoy a physiological state that supports spontaneous social engagement behaviors. Social engagement, neurologically speaking, is a state based on the activity of five cranial nerves: the ventral branch of the vagus nerve (cranial nerve X), and pathways within cranial nerves V, VII, IX, and XI.
