Maternal and infant behaviors of 30 American and 52 Japanese mother/infant dyads from middle-class homes were compared. The major differences in caretaker behavior were (1) the Japanese mothers spent more time with or in the presence of their babies than did the American mothers, and (2) the American mothers were more active in positioning the bodies of their infants. Infant behaviors between the two cultures were strikingly similiar. Significant differences were found in sucking behavior, with the American babies displaying more sucking behavior than the Japanese babies. Male babies of both cultures were awake more and received more rocking than did females. Several culture by sex interactions were found. Japanese males displayed significantly higher unhappy and total vocal behavior than Japanese females, but the American males displayed significantly lower total vocal behavior than the American females. Comparisons were made with findings from a study conducted in 1969. The findings highlight the importance of cultural context in investigating early behaviors. (Author/RH)