The Strange Situation procedure was formulated to observe attachment relationships between a caregiver and children between the age of nine and 18 months. It was developed by Mary Ainsworth, a developmental psychologist. Originally it was devised to enable children to be classified into the attachment styles known as secure, anxious-avoidant and anxious-ambivalent. As research accumulated and atypical patterns of attachment became more apparent it was further developed by Main and Solomon in 1986 and 1990 to include the new category of disorganized/disoriented attachment.
In this procedure the child is observed playing for 20 minutes while caregivers and strangers enter and leave the room, recreating the flow of the familiar and unfamiliar presence in most children's lives. The situation varies in stressfulness and the child's responses are observed. The child experiences the following situations:
Mother (or other familiar caregiver) and baby enter room.
Mother sits quietly on a chair, responding if the infant seeks attention.
A stranger enters, talks to the mother then gradually approaches infant with a toy. The mother leaves the room.
The stranger leaves the infant playing unless he/she is inactive and then tries to interest the infant in toys. If the infant becomes distressed this episode is ended.
Mother enters and waits to see how the infant greets her. The stranger leaves quietly and the mother waits until the baby settles, and then she leaves again.
The infant is alone. This episode is curtailed if the infant appears to be distressed.
The stranger comes back and repeats episode 3.
The mother returns and the stranger goes. Reunion behaviour is noted and then the situation is ended.
Two aspects of the child's behaviour are observed:
The amount of exploration (e.g. playing with new toys) the child engages in throughout, and
The child's reactions to the departure and return of its caregiver.