Social engagement and attachment: a phylogenetic perspective

Ann N Y Acad Sci. 2003 Dec;1008:31-47. doi: 10.1196/annals.1301.004.


This article focuses on the importance of social engagement and the behavioral and neurophysiological mechanisms that allow individuals to reduce psychological and physical distance. A model of social engagement derived from the Polyvagal Theory is presented. The model emphasizes phylogeny as an organizing principle and includes the following points: (1) there are well-defined neural circuits to support social engagement behaviors and the defensive strategies of fight, flight, and freeze; (2) these neural circuits form a phylogenetically organized hierarchy; (3) without being dependent on conscious awareness, the nervous system evaluates risk in the environment and regulates the expression of adaptive behavior to match the neuroception of a safe, dangerous, or life-threatening environment; (4) social engagement behaviors and the benefits of the physiological states associated with social support require a neuroception of safety; (5) social behaviors associated with nursing, reproduction, and the formation of strong pair bonds require immobilization without fear; and (6) immobilization without fear is mediated by a co-opting of the neural circuit regulating defensive freezing behaviors through the involvement of oxytocin, a neuropeptide in mammals involved in the formation of social bonds. The model provides a phylogenetic interpretation of the neural mechanisms mediating the behavioral and physiological features associated with stress and several psychiatric disorders.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Adaptation, Psychological
  • Autonomic Nervous System / physiology
  • Awareness / physiology
  • Child
  • Defense Mechanisms
  • Environment
  • Fear
  • Humans
  • Interpersonal Relations
  • Nerve Net / physiology
  • Object Attachment*
  • Oxytocin / physiology
  • Phylogeny*
  • Psychological Theory*
  • Social Behavior*
  • Vagus Nerve / physiology*


  • Oxytocin