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 measures
Developed by Carol George and Malcolm West in 1999, this is a free response task that involved telling stories in response to eight picture stimuli (1 warm-up & 7 attachment scenes). A good description can be found in George and West's 1999 paper in the journal Attachment and Human Development. A book describing the measure is forthcoming from Guilford Press in spring 2011.