Harlow’s study of the monkeys demonstrated attachment and the importance of attachment in relationships. The baby monkeys were removed from their mothers and offered two wire mothers instead. One was covered in soft towel and the other provided food but was hard. The monkey’s preferred to spend time gaining comfort from the towel monkey and were better adjusted physically and mentally if they chose to.
Robertson and Robertson carried out naturalistic observations in hospitals to discover the effects of deprivation when children were admitted. Spitz also studied children in hospitals and they both found that separation and deprivation were harmful.
His theory has changed views on child rearing and caused positive change in policy and practice – children are now better off in hospitals. For example, we use key workers in institutions and children are better cared for by society and we are less reluctant to separate children from their families.
Animal studies might not be generalisable to humans which affects the validity of Harlow and Lorenz’s findings when applied to human attachment.
The mother’s role is exaggerated by Bowlby – he lacks a focus on the importance of the father. Other research such as Schaffer and Emerson has shown that babies can form multiple attachments, not just one.
The theory suffers from both class and cultural bias – it promotes a British middle-classed ideal of what good parenting was.