Developmental psychology
Attachment theory, originally developed by John Bowlby, focuses on the importance of open, intimate, emotionally meaningful relationships. Attachment is described as a biological system or powerful survival impulse that evolved to ensure the survival of the infant. A child who is threatened or stressed will move toward caregivers who create a sense of physical, emotional and psychological safety for the individual. Attachment feeds on body contact and familiarity. Later Mary Ainsworth developed the Strange Situation protocol and the concept of the secure base.
Attachment in adults
Mary Ainsworth and John Bowlby founded modern attachment theory on studies of children and their caregivers. Children and caregivers remained the primary focus of attachment theory for many years. Then, in the late 1980s, Cindy Hazan and Phillip Shaver applied attachment theory to adult relationships. Hazan and Shaver noticed that interactions between adults shared similarities to interactions between children and caregivers. For example, romantic or platonic partners desire to be close to one another. Adults feel comforted when their attachments are present and anxious or lonely when they are absent. Romantic relationships, for example, serve as a secure base that help people face the surprises, opportunities, and challenges life presents. Similarities such as these led Hazan and Shaver to extend attachment theory to adult relationships.