A major goal for advertising is to have an enduring emotional impact on an audience by facilitating their creation of personally relevant understandings of an advertisement. This is achieved through a process of cocreation in which consumers integrate advertising content with their own attitudes, beliefs, and values to produce the meaning of an advertisement. This article proposes an approach to evaluating advertisements that builds on the reconstructive nature of memory, the dominant view of memory today. The reconstructive view of memory holds that the memory for the same event is different each time it is recalled and that the person doing the recalling is unaware of these changes. We present an experimental paradigm that assesses advertising's influence on consumers' own memory of their beliefs. We demonstrate that advertising can unconsciously alter consumers' beliefs as reflected by a change in how consumers recall their earlier reporting of these beliefs following an advertising exposure. That is, advertising that causes consumers to remember differently earlier (preadvertising exposure) reported beliefs and in which the change is in the direction of the advertisement's message is an advertisement that contains information the consumer has unconsciously adopted as their own and therefore is likely to be personally relevant and to have an enduring impact on their emotions.