In sum, the best way in which to change attitudes that serve the knowledge function is to focus on facts and arguments and to anticipate how consumers will use these facts and arguments while thinking and reasoning about an ad. Promotion-focused knowledge ads rely on strong arguments in the form of factual, logical, and comparative ads to encourage consumers to form favorable brand attitudes that are held with a high degree of certainty and confidence. In contrast, prevention-focused knowledge ads use mystery, surprise, and confusion to reduce certainty and, thereby, to encourage consumers to be more open-minded. Open-minded consumers are more likely to try new brands that they have never used before. Knowledge appeals work best for complex products with a large number of attributes.