This paper describes five experimental studies which explored the influence of fathers' home caregiving and interactional characteristics on their infant's laboratory behavior. Approximately 300 families with children ranging in age from 6 to 24 months were studied. Each infant's reactions were observed as a function of the manipulation of the presence and absence of the mother, the father, and a female stranger in the playroom. In one study, a direct attempt was made to increase the amount of father interaction at home in order to observe any effects on the infant's laboratory behavior. Problems of methodology are discussed, and father-caregiving patterns noted. While a relationship to the father was seen to be independent of the father's involvement in child care, some minimal level of interaction seemed necessary. Extensive paternal caregiving was related to the preferences for the father in the laboratory and shortened duration of separation protest. The final study demonstrated that manipulation of father-infant interaction at home directly influences infant-father interaction in a laboratory setting. (Author/BRT)