Before revision: First Edition (1969 - 1993) In 1983, 25 low-risk mother-infant pairs participated in a research project to predict the performance of 21 month olds on the Mental Scale of the Bayley Scale of Infant Development (BSID-1) from characteristics of infants and mothers.
After revision: First Edition (1969 – 1993) In 1983, 25 low-risk mother-infant pairs participated in a research project to predict the performance of 21 month olds on the Mental Scale of the Bayley Scale of Infant Development (BSID-1) from characteristics of infants and mothers.