"The ventral vagal system is involved with most aspects of social contact and pleasure. It guides eye contact, hearing, eating, speech, singing, nursing, kissing, smiling, and some would say, direct heart to heart contact. Because of its role in making contact between different people favorable, the ventral-vagal system is a way of achieving personal safety, but it requires a moderate amount of actual safety to develop or stay employed. That is why prolonged danger or stress, or stress or danger early in life, tends to atrophy or impair the development of, the ventral vagal system."
https://reichandlowentherapy.org/Content/Vegetative/ventral_shift.html
