maternal deprivation

• The theory of maternal deprivation is supported by Bowlby's (1944) 44 Thieves study as the findings support the idea that maternal deprivation can have long term emotional consequences such as affectionless psychopathy.

  Therefore, the theory has real-life application as it can help us to understand why many psychopathic criminals lack empathy for their victims and can help to create research interventions for children who experience separation.
• However, a limitation of the study is the methodological flaws since Bowlby designed and conducted the self-reports himself and so his presence and interpretation may have influenced the outcome of the research (researcher bias).

  This decreases the internal validity of the findings as the results may not be an accurate representation of the long term effects of maternal deprivation.
• Lewis et al (1954) partially replicated the 44 thieves study on a larger scale by including 500 young participants. In her sample, a history of maternal deprivation did not predict criminality or difficulty forming close relationships.

  This is a limitation of Bowlby's theory as it suggests that other factors may affect the outcome of early maternal deprivation.
• Later research has found that the effects of maternal deprivation are not inevitable as Bowlby suggested. For example, Koluchova found that a case of twin boys who were isolated for more than five years, appeared to recover fully when they were looked after by two loving adults.

  This conflicting evidence suggests that the critical period is more of a sensitive period and that damage may not be irreversible and inevitable as Bowlby claimed.