Bowlby’s maternal deprivation hypothesis suggests that bond disruption between the infant and caregiver in the early years can have detrimental and irreversible effects on the intellectual, social, and emotional development of the child. He carried out the study on 44 juvenile thieves (that were transferred to his institution), whom he compared to a group of 44 controls. It was a retrospective study using interviews and questionnaires. He diagnosed the participants by whether or not they were affectionless psychopaths – disorder resulting in lack of remorse or guilt. He found that 32% of the thieves and none of the controls were affectionless psychopaths. Of the affectionless psychopaths, 86% had experienced early separation. In contrast, only 17% of the controls had been deprived in their early days. Firstly, his results showed that maternal deprivation can have serious negative effects [i.e. affectionless psychopathy] that can be lasting and observable even several years later. Secondly, his findings led to many other researchers to study the link between deprivation and emotional development, of which they found strong links. Although Bowlby’s findings show that maternal deprivation has serious consequences, other research has shown that this is not always true. Bowlby defined a critical period during which he suggested that attachment bonds were most important. However, research has shown that although there may be just a sensitive period during which attachments are important but not essential.
The twins studied by Koluchova (1991) are a clear example of the idea that the effects of deprivation can be reversed. When found, the twins were barely able to talk, and lacked immensely on social skills because they had spent the past 9 years of their life locked in a cellar. However, by the age of 20, they were of above average intelligence, and had brilliant inter-social skills.