Objective: To compare the physical, cognitive, and motor development of infants adopted from foster care with infants adopted from institutions.
Method: Forty-two formerly fostered and 50 post-institutionalized girls adopted from China, aged between 11 and 16 months on arrival, were visited 2 and 6 months after adoption. Children's height, weight, and head circumference were measured. Stress regulation was assessed by diurnal salivary cortisol levels, and cognitive and motor development were assessed using the Bayley Scales of Infant Development-second edition.
Results: At both assessments, the (modest) physical growth delays were similar for formerly fostered and post-institutionalized children. For weight and head circumference (but not for height) a catch-up over time was found, with a significant interaction between time and age at arrival, showing a more rapid catch-up for earlier adopted children. The daily cortisol curves of the formerly fostered and post-institutionalized children were similar and did not change over time. At both assessments, the former foster children outperformed the post-institutionalized children on mental and motor skills. Both groups showed a similar catch-up for mental development. For motor development, no catch-up was found.
Conclusions: The influence of pre-adoption foster versus institutional rearing seems more pronounced for cognitive and motor development than for physical development and hormonal stress regulation. Our outcomes suggest that pre-adoption foster care is less detrimental to children's cognitive and motor development than institutional rearing.