Text manipulations influence children's understanding of class inclusion hierarchies.

Second, fourth, and sixth grade children were presented with a passage which could be represented as a four-level class inclusion hierarchy. Top-down or bottom-up presentation of material and repetition or no repetition of category labels were manipulated in a 2 x 2 design. Children were requested to construct an external representation for the passage and to respond to questions requiring them to reason about its contents. Quality of representation and performance on the question task were related to grade level and to the text manipulations. Implications of the results, particularly as related to education, are discussed.