A landmark study by O'Neill (1996), in which 2-year-old children were found to be more likely to point toward a hidden object to help an adult who was unsighted during the hiding event than to point helpfully for an adult who had been sighted, seems to undermine the conventional assumption that children this young do not understand the relationship between seeing/not seeing and knowing/not knowing. Concerns remain, however, as to whether the children's success was mentalistic or behavioral. In two experiments, 2-year-old children received first-person experience with two kinds of glasses of different colors but with apparently identical opaque lenses, one of which blocked their vision and the other of which they could see through. When the parent was wearing these glasses, the children were able to use their own first-person experience of the glasses to infer whether the adult could see or not. Despite this, they did not understand the causal relationship between visual perception and knowledge formation, as demonstrated by their indiscriminate pointing behavior in response to an ignorant or a knowledgeable parent. However, in a third experiment, we examined the relationship between experience of the adult's behavioral incompetence when wearing glasses of a certain color and the children's pointing behavior. Here they tended to point appropriately. We conclude that the phenomenon reported by O'Neill (1996) yields to an account in terms of the 2-year-olds' assumptions about behavioral competence/incompetence rather than about knowledge/ignorance. (Contains 3 tables, 2 footnotes, and 4 figures.)