Past research on the development of referential communication abilities in children does not provide a basis for explaining precisely why communicative effectiveness increases. The common assumption is that developments in role-taking facilitate the child's ability to adapt to hearers. A reasonable alternative explanation is that a child's referential messages become clearer as the child's perceptual skills improve and language becomes increasingly socialized. To assess the alternatives, a common set of referent materials was used in two separate tasks given to first and third grade children. One group described referents in a context where no intent was specified, and the other group described referents in a context where an interpersonal communicative purpose was specified. Referential messages were assessed for their clarity, and it was concluded that both age and a specified communication purpose affect the clarity of children's referential messages, but both older and younger children construct clearer messages when their purpose is specified as interpersonally communicative. In addition, females became clearer while males became less clear, on the second trial of the task. (Author/MAI)