A weakness of Bowlby's maternal deprivation hypothesis?

-Lack of consistent support for long-term effects as most attempts to replicate the 44 thieves study failed to produce similar results -Lewis (1954) looked at 500 young people and found no association between early separation and later psychopathy. -Barrett (1997) found that securely attached children are more resistant to negative effects of maternal deprivation in compariosn to insecurely attached children. -Casts doubt on Bowlby's theory as it suggests that other facts, like individual differences and attachment types, may be implicated in the mediation of the consequences of maternal deprivation