||Consumers often compare two products on the basis of verbal descriptions of their features. Some features may be mentioned in both descriptions, whereas others may be mentioned in one description but not the other. This thesis is concerned with how people use common and unique features of product descriptions both to choose between products and to evaluate each product individually. It also examines the extent to which the effects of these different types of features on product evaluations persist over time. Finally, it considers the effects of different types of features on product evaluations under conditions in which consumers are not explicitly asked to compare the products at the time they receive the product information. Results from two studies showed that the cancellation effects and the direction-of-comparison effects were replicated when participants were explicitly told to compare the products at the time they received product information. However, when they were not told to compare at the time of product presentation, the cancellation effects were reduced, whereas the direction-of-comparison effects were unaffected. Moreover, the cancellation effects reduced substantially over time, suggesting that common features gain more influence as time goes on.