Effects of infant sociability and the caretaking environment on infant cognitive performance.

40 middle-class mothers and their 12-month-old infants participated in an examination of the extent to which infant sociability and infant home experiences were correlated with cognitive capacity. Results indicated that the measures of the home environment (including Caldwell's Home Observation for Measurement of the Environment [HOME] inventory) were not correlated with the measures of cognitive competence (Bayley Mental Development Index [MDI], Ordinal Scales of Psychological Development) except among firstborns. Measures of the home environment were, however, correlated with measures of infant sociability (assessed inside and outside the test situation): sociable infants had sociable mothers. The infants' reactions to strange adults clearly influenced their performance in testing situations. Strong relationships were found between both measures of sociability and both measures of cognitive competence. The sociable friendly infants received higher scores on both cognitive tests than the less sociable babies did.