Early attachment security, subsequent maternal sensitivity, and later child development: does continuity in development depend upon continuity of caregiving?

In order to test the hypothesis (1) that the most competent 3-year-olds would be those with histories of secure attachment (at 15 months) who subsequently experienced (relatively) high-sensitive mothering (at 24 months), (2) that the least competent children would be those with histories of insecure attachment who subsequently experienced (relatively) low-sensitive mothering, and (3) that those with mixed or inconsistent attachment-sensitivity histories would fall in between, data gathered as part of the NICHD Study of Early Child Care were examined. A-priori tests supported the hypothesis in the case of all five developmental outcomes examined (problem behavior, social competence, expressive language, receptive language, school readiness), though group means did not always rank in the predicted direction. Further planned comparisons of children with mixed attachment-sensitivity histories revealed that, in the case of all outcomes, insecurely attached children who subsequently experienced high-sensitive mothering significantly outperformed secure children who subsequently experienced low-sensitive mothering. Follow-up analyses highlighted the role of maternal and family stress in accounting for why some infants who were classified as secure at 15 months experienced low-sensitive mothering at 24 months and why some infants classified as insecure subsequently experienced high-sensitive mothering. Results are discussed with regard to the role of early experience in shaping development.