Why and how some individuals are more resilient and others more vulnerable, is a question that has perplexed me and other scientists who study trauma and the clinicians who work with the survivors. Coincident with my acknowledgment that there were variations in responses to stressful and traumatic events, Polyvagal Theory emerged. The theory was a product of a consolidation of the information I had gained from decades of questioning about how bodily state influenced our interactions with others and at times distorted our perspective.

Polyvagal Theory provided a conceptualization of how physiological state and the regulation of physiology were intertwined in both resilience and vulnerability. The theory helped fill a gap in our understanding of human behavior and provided an understanding of the mechanisms that determine vulnerability to traumatic events.