Aims: Study the effects of late adoption
Procedure: In a longitudinal study using interviews and questionnaires, two groups of children were followed. All of these children had been taken into care before they were six months old and had stayed there until they were at least two years old. One of the groups was made up of children who had subsequently been adopted, the other group consisted of children who had been returned to their natural families. Both groups were compared against a "control" group of children, who had been brought up in a normal family environment.
Findings: At age sixteen, the "adopted" children showed similar family relationships to the control group. However, the group of children who had been returned to their parents showed poor family relationships and characteristics of "affectionless psychopathy".
Conclusion: Maternal deprivation during the critical period of development is not in itself a cause of long-term problems for children.
Strength: This study provides evidence that challenges Bowlby's hypotheses that maternal deprivation during the critical period inevitably leads to long-term damage and also that the most important attachment figure for a child is its natural mother.
Weakness 1: The research findings rely on the answers given by interviewees, which may not always be reliable.
Weakness 2: It has been shown ("Genie") that the effects of maternal deprivation can be mitigated: the researchers in this study may have acted unethically by allowing it to carry on until the children reached age sixteen, in spite of the fact that they would have realised before then that the "returned" children were at a disadvantage.