Robertson & Robertson - PDD Model
Method: In a naturalistic observation, several children who experienced short seperations from their carers were observed and filmed. For example, a boy called John aged around 18 months stayed in residential nursery for nine days while his mother had another baby.
Results: John showed signs of passing through 'protest' for the first day or two. Then he showed despair - he tried to get attention from the nurses but they were busy with other children so he 'gave up' trying. Then he showed detachment - he was more active and content. However, when his mother came to collect him, he was reluctant to be affectionate.
Conclusion: The short-term seperation had very bad effects on John, including possible permanent damage to his attachment with his mother.
Evaluation: John's reaction might not have been due to seperation - it could have been down to his new environment or the fact that he was getting much less attention than he was used to. There will have been little control of variables, and it would be difficult to replicate each individual situation. However, as the study took place in a natural setting, the results will have ecological validity but will be less reliable.
Bowlby - The 44 Juvenile Thieves
Method: Case studies were compled on the backgrounds of 44 adolescents who had been referred to the clinic where Bowlby worked because they'd been stealing. There was a control group of 44 'emotionally disturbed' adolescents who didn't steal.
Results: 17 of the thievves had experiences frequent seperations from their mothers before the age of two, compared woth 2 in the control group. 14 of the thieves were diagnosed as 'affectionless psychopaths' (they didn't care about how their actions affected others). 12 of these 14 had experiences seperation from their mothers.
Conclusion: Deprivation of the child from its main carer early in life can have very harmful long-term consequences.
Evaluation: The results indicate a link between deprivation and criminal behaviour. However, it can't be said that one causes the other. There may be other factors that cause the criminal behaviour. Although case studies provide a lot of detailed information, the study relied on retrospective data, which may be unreliable.