separation - the child is not in the presence of the primary caregiver, brief separations, particularly when the child is with a substitute caregiver, don't have a significant impact on development
deprivation - the child loses an element of the primary attachment figure's emotional care/love, this then becomes an issue for development
extended separations can lead to deprivation, which causes harm
Bowlby's maternal deprivation hypothesis
the crucial time for a child's psychological development is 30 months
if a child is deprived from their mother during this time, it can lead to serious psychological harm
44 thieves - procedure
Bowlby selected a sample of cases from the many children he had worked with at his clinic in London
he identified 44 thieves (14 of which were classed as psychopaths) and 44 non-thieves for comparison
he recorded the number who had experienced frequent sepearations from their mother before aged 2
44 thieves - findings
86% of affectionless thieves experienced frequent separations before age 2, compared with 17% of other theives and 4% of controls
44 theives - conclusions
maternal deprivation is linked to criminality and perhaps to emotionless psychopathy
evaluation
generalisable as it supports his maternal deprivation theory
could hinder his results as it is his own research supporting his own theory so it may be bias as he may have interpreted his results differently (researcher bias) - lacks internal validity
Levy et al supported this as he found that when baby rats were separated from their mothers for even just a day, this had a permanent impact on the social development - supporting Bowlby (external validity)
Bowlby's study had a positive impact on how people thought about childrearing post war - Robertson filmed a two year old girl during her 9 day stay in a hospital and found that she was frequently distressed and begging for her mother - high external validity