In the studies presented here, infants' understanding of others' attention was assessed when gaze direction cues were not diagnostic. Fourteen-, 18- and 24-month-olds witnessed an adult look to the side of an object and express excitement. In 1 experimental condition this object was new for the adult because she was not present while the child and someone else played with it earlier. Children responded to this as if they assumed that the adult was excited about this new object as a whole. In the other condition the object was one with which the infant and this adult had just previously played for a minute. In this case children appeared to assume that the adult could not be excited about this object in itself. They responded either by attending to a specific part of the object or, more frequently, by looking around the room for another object. These results suggest that 1-year-olds can determine what others are attending to based on a pragmatic assessment of what is new and what is old for them combined with a form of reasoning by exclusion. (Contains 3 figures and 1 footnote.)