Origins and Core Concepts of Attachment Theory
Attachment theory was systematised by the British psychiatrist John Bowlby (1907-1990) over the period running from the 1950s to the 1980s. Observing children in orphanages in the aftermath of the Second World War, Bowlby concluded that the emotional bond between an infant and a caregiver, which he called attachment, is indispensable to healthy development. The central function of attachment is to provide a secure base: the child uses the caregiver as a base from which to explore the surrounding world, returning to the caregiver for reassurance whenever something feels threatening. Drawing on evolutionary reasoning, Bowlby argued that the attachment behavioural system is an adaptive mechanism naturally selected for its contribution to survival. Through repeated interaction with the caregiver, the child builds up an internal working model, a cognitive representation of the self and of others that encodes such basic beliefs as "am I worthy of being loved?" and "can other people be trusted?"
Ainsworth's Strange Situation Procedure and the Attachment Styles
To test Bowlby's theory empirically, Mary Ainsworth (1913-1999) developed the Strange Situation Procedure. In this experiment an infant aged between 12 and 18 months is brought into a laboratory with the mother, and the infant's reactions are observed as a stranger enters and as the mother leaves and later returns. From these observations Ainsworth identified three attachment styles. The secure infant uses the mother as a base for exploration, shows distress on separation, and settles quickly once she comes back. The anxious-resistant infant is extremely reluctant to be parted from the mother and, on reunion, alternates between anger and approach. The avoidant infant appears indifferent to the mother's presence and shows no distress at separation. A fourth category, disorganised attachment, was added later by Main and Solomon (1986).
Adult Attachment and Its Application to Romantic Relationships
In 1987 Cindy Hazan and Phillip Shaver published a landmark paper extending Bowlby's attachment theory to adult romantic relationships. They showed that adult romantic bonds rest on attachment processes of the same kind found in the infant-caregiver relationship, and demonstrated empirically that secure, anxious, and avoidant attachment styles can all be identified in adults. Bartholomew and Horowitz (1991) subsequently proposed a model defining four attachment styles along two dimensions, the model of self (positive or negative) and the model of others (positive or negative). Research on adult attachment makes it fairly concrete what a given pairing tends to run into. Couples in which both partners are secure report the highest relationship satisfaction, while the pairing of an anxious partner with an avoidant one falls readily into the pursue-withdraw pattern. What matters most is that attachment style is not fixed: it can change through the experience of a stable relationship. What a combination of attachment styles describes is the present state of what the two partners expect from each other. The internal working model was assembled out of repeated exchanges with a caregiver, and it goes on being rewritten by whether the person now beside you responds the way that model predicts. Even in an anxious-avoidant pairing, the pursue-withdraw loop breaks on the spot once the pursuing partner stops treating a slow reply as a sign of being abandoned and the withdrawing partner can explain distance as a way of settling rather than an act of hostility. The capacity for change noted above shows up as those breaks, accumulated.