Vulnerability to emotional disorders is thought to lie in memory representations (e.g. negative self-schemas) that are activated by triggering events and maintain negative mood. There has been considerable uncertainty about how the influence of these representations can be altered, prompted in part by the development of new metacognitive therapies. This article reviews research suggesting there are multiple memories involving the self that compete to be retrieved. It is proposed that CBT does not directly modify negative information in memory, but produces changes in the relative activation of positive and negative representations such that the positive ones are assisted to win the retrieval competition. This account is related to the treatment of common symptoms typical of emotional disorders, such as phobic reactions, rumination, and intrusive images and memories. It is shown to provide a parsimonious set of principles that have the potential to unify traditional and more modern variants of CBT.