Abstract

This chapter presents the attachment system as the biological substrate of close relationships, beginning in the complete dependence of infants on caregivers. The attachment system operates to keep young children close to their parents for protection, nurturance, and learning. Attachments are particularly profound in humans because of the lengthy juvenile period of dependency. Complementary to the infant’s attachment system, caregivers have a caregiving system that guides their behavior. The biology of the attachment system is discussed in terms of localization, brain chemistry, and neural circuits. Separation from an attachment figure induces fear and activates the hypothalamus–pituitary–adrenal axis. Attachment behaviors (cuddling, kissing, and mutual gaze) sooth attachment distress. Adult attachments, including friendships, are exapted from the infant attachment system, but differ from it in mutuality. This chapter concludes with a critique of the instrumentalism built into attachment theory and a description of a constitutive alternative.