Verbal and nonverbal interaction of mothers with their down's syndrome and nonretarded infants.

While it appears probable that parental expectancies due to early knowledge of the condition of Down's syndrome in infants affects parent-child interactions, little data are available showing how interactions are affected. In an observational, laboratory-based study, we compared verbal and nonverbal interactions between 10 mothers and their Down's syndrome infants and 10 mothers and their nonretarded infants. Although there was no difference between the groups in mothers' language complexity, mothers of Down's syndrome children spoke at a significantly faster rate. Observational measures of infants showed that Down's syndrome babies smiled and vocalized less, but mothers in the two groups failed to differ significantly on the nonverbal interactional behavior observed. The results were discussed in relation to the conclusions of other investigators who have speculated that language delays in Down's syndrome children may be due in part to differences in the environment provided by caregivers.