PDD Model- Robertson and Bowlby (1952)
Children separated from their mother sometimes showed a behaviour pattern that could be characterised in the following three stages:
1) Protest; crying, along with panic. The child would cling to the parent and struggle to escape from others that attempt to pick them up.
2) Despair; loss of hope and child is apathetic. They show little interest in their surroundings and show self comforting behaviours, appearing withdrawn and uninterested.
3) Detachment; child calms down. They seem less distressed compared to before and does not respond to the caregiver when they are re-united. Robertson and Bowlby thought the lack of distress was a disguise of true feelings.