Children's cognizance of linguistic selectional rules was studied in a controlled sentence production task. Forty-five third grade and 45 sixth grade children wrote noun responses in active and passive sentence frames in which only verbs and function words were given. The verbs varied in how animate nouns were required as both logical subjects and objects. It was found from measures of response animateness that the selectional rules were followed for both subjects and objects, and verb classes defined for both together. Animate responses were favored in the noun position before verbs, indicating the presence of a response bias. (Author/FWB)