A series of experiments investigated 5- to 17-month-olds' comprehension of adults' direction of gaze and manual pointing behaviors. Findings indicated that a change in the adult's direction of gaze and orientation of head does not seem sufficient to enable the infant to reliably localize a referent when the infant must choose between pairs of identical targets on the same side of the visual field. Strong evidence for comprehension of referential communication was obtained when the adult not only looked but also pointed at the correct target. Babies of 10 months and older accurately localized the target regardless of whether it was to the right or left of the visual field, even when a competing, identical target had to be ignored. Tentative evidence indicated that the ability to comprehend pointing may first arise for targets in the right side of the field of vision between 5 and 9 months of age, and may become bilateral toward the end of the first year. (Author/RH)