The present study investigated whether infants of mothers who were depressed postpartum would behave like infants of non-depressed mothers who simulated depression. A total of 24 mothers and their 3-month-old infants were videotaped during face-to-face interactions. All mothers were given the Beck Depression Inventory (BDI) and the State-Trait Anxiety Inventory. Mothers receiving scores of 16 or above on the BDI were recruited for the depressed group; non-depressed mothers with BDI scores of 4 or less were selected from the random sample to match depressed subjects on age, parity, socioeconomic status, and education. Interactions were recorded in which mothers were instructed to behave spontaneously, to simulate depression, and to again behave naturally. Recordings for each type of behavior were 3 minutes long. Infant behaviors coded were frequency of vocalizations, positive and negative facial expressions, and duration of looking away, protesting, and looking wary. Tapes were separately coded for similar behaviors of the mother. Additionally recorded were infants' and mothers' baseline and interaction heart rates and infants' activity levels. Results suggest that the infant is able to detect the affective quality of the mother's displays and appropriately modify affective displays in response to them; depression in the mother may be transmitted to her offspring during their very early interactions. (RH)