Attachment theory is the joint work of John Bowlby and Mary Ainsworth (Ainsworth & Bowlby, 1991 ). Drawing on concepts from ethology, cybernetics, information processing, developmental psychology, and psychoanalysts, John Bowlby formulated the basic tenets of the theory. He thereby revolutionized our thinking about a child’s tie to the mother and its disruption through separation, deprivation, and bereavement.

Mary Ainsworth’s innovative methodology not only made it possible to test some of Bowlby’s ideas empirically hut also helped expand the theory itself and is responsible for some of the new directions it is now taking. Ainsworth contributed the concept of the attachment figure as a secure base from which an infant can explore the world. In addition, she formulated the concept of maternal sensitivity to infant signals and its role in the development of infant-mother attachment patterns.