This book has devoted more than the usual amount of space Lo processes underlying the formation of beliefs, attitudes, and intentions, as well as to the prediction of behavior. Part Ill demonstrates the relevance of these processes for an understanding of the problems associated with attempts to bring about change Chapter 9 develops some fundamental principles of change. We shall see that attempts to bring about change invariably involve exposure to new informalion about some object, behavior, issue, or event, Changes in beliefs resulting from such exposure to new information provide the foundation on which rests the ultimate effectiveness of any influence attempt. We will try to show that attempts to induce change in a given belief, attitude, intention, or behavior must take into account the relation between the variable that is to be changed and the beliefs that are affected most immediately by the influence attempt. Studies attempting to produce change in a given variable can only lead to inconsistent findings if the beliefs underlying that variable are not well understood, In Chapter 10 we shall active participation on the part of the subject as a for providing