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.
History of attachment theory
In his 1951 monograph for the World Health Organization, "Maternal Care and Mental Health", Bowlby put forward the hypothesis that "the infant and young child should experience a warm, intimate, and continuous relationship with his mother (or permanent mother substitute) in which both find satisfaction and enjoyment" and that not to do so may have significant and irreversible mental health consequences. This proposition was both influential in terms of the effect on the institutional care of children, and highly controversial. There was limited empirical data at the time and no comprehensive theory to account for such a conclusion.