Attachment and Health
John Bowlby and Mary Ainsworth developed attachment theory in the 1960s while investigating the effects of maternal separation on infant development. The development of the Strange Situation task in 1965 by Ainsworth and Wittig allowed researchers to systematically investigate the attachment system operating between children and their parents. The Strange Situation involves separating infant-parent dyads and observing infant behaviours upon reunion. Infant behaviour tended to follow patterns, leading to the development of three attachment categories: Secure, Anxious-Avoidant, and Anxious-Resistant. In 1990, Ainsworth added a new category, championed by Mary Main, called Disorganized/Disoriented attachment, characterized by its less reliable pattern of behaviour.
Attachment parenting
Stress has been surveyed and documented in many studies. The theoretical foundation was created in the 1960s by Richard Lazarus. In 1974, Hans Selye introduced the differentiation between distress and eustress, and in 1984, psychoanalyst Heinz Kohut proposed the concept of "optimal frustration"; Kohut postulated that the harmony between parents and child needs some well allotted disruption in order to empower the child to develop a healthy personality. In resilience psychology, too, there is broad agreement today that it harms children if their parents keep any stress away from them indiscriminately; by doing so, they suggest to the child that everyday problems are painful and overall to be avoided.