We examined the effects of knowledge, motivation, and the type of message on ad processing and on product judgments. The data suggest that, regardless of subjects' prior knowledge, they could be motivated to process message information in detail. However, experts and novices differed in the types of information that prompted detailed message processing. Experts are more likely to process a message in detail when given only attribute information, while novices are more likely to do so when given benefit (or benefit and attribute) information. Experts and novices also differed in how they processed messages; experts' detailed message processing was evaluative, while novices' was more literal.