Attachment theory is an approach to studying relationships between people, which focuses on the nature of the bonds which children establish with caregivers. The theory was proposed by English psychiatrist John Bowlby in 1951, based on evidence that parental care seems to be an important factor for a person’s mental health as an adult (1).
Additional empirical support for the attachment theory approach was later provided by Bowlby’s collaborator Mary Ainsworth, in part from the development of a study procedure called the strange situation. In this procedure, infants interacted with their caregiver within a given environment, and their reactions to the caregiver leaving the room and re-entering were observed, as well as an alternative scenario in which an adult stranger was present in the room. Based on distinctive behaviour patterns observed in the procedure as well as observations of the same infants in their home environment, a classification system for styles of attachment was devised (2). Ainsworth identified three main attachment styles: secure attachment, insecure avoidant attachment and insecure ambivalent/resistant attachment, and concluded that the category in which a child fell, was the result of early interactions with the caregiver (3).
Sources:
1. Bowlby, J. (1951). Maternal care and mental health. World Health Organization Monograph Series, 2, 179.
2. Bretherton, I. (1992). The origins of attachment theory: John Bowlby and Mary Ainsworth. Developmental Psychology, 28(5), 759-775.
3. Ainsworth MD, Blehar M, Waters E, Wall S (1978). Patterns of Attachment: A Psychological Study of the Strange Situation. Hillsdale NJ: Lawrence Erlbaum Associates, 59-63
See lecture on attachment: What We All Need to Know About Attachment, Jon G. Allen
Further Reading:
http://internal.psychology.illinois.edu/~rcfraley/attachment.htm