Cultural variation in relations and moment-to-moment contingencies of infant-mother person-oriented and object-oriented interactions were compared in 118 Japanese, Japanese American immigrant, and European American dyads with 5.5-month-olds. Infant and mother person-oriented behaviors were related in all cultural groups, but infant and mother object-oriented behaviors were related only among European Americans. Infant and mother behaviors within each modality were mutually contingent in all groups. Culture moderated lead-lag relations: Japanese infants were more likely than their mothers to respond in object-oriented interactions; European American mothers were more likely than their infants to respond in person-oriented interactions. Japanese American dyads behaved like European American dyads. Interactions, infant effects, and parent socialization findings are set in cultural and accultural models of infant-mother transactions. (Contains 2 tables.)