This study examined how consumer evaluations of products are influenced by two factors: the degree of congruity between products and their associated category schema and the level of consumers' involvement with the evaluation task. It was hypothesized that when product information is congruent with category schema, category-based processing occurs, resulting in assimilation effects; when it is incongruent, contrast or piecemeal processes are used, depending on the level of consumers' involvement. The results generally supported the prediction. Theoretical and managerial implications of the results are discussed.