You have now read about the major approaches developed by psychologists to study attitudes and persuasion. Each of these approaches was at one time or another thought possibly to provide a very general explanation for why peoples' attitudes change. Because proponents of each approach attempted to explain a wide variety of phenomena, the different approaches often provided competing interpretations for the results of a particular experiment. Interestingly, research designed to allow a choice between two different ways to explain some data (crucial experiments) has not led to any of the approaches being abandoned. Instead, the domains of the different approaches have been narrowed. We now know, for example, that rewards do not always increase persuasion and that all changes in attitudes are not based on a consistency motive but that each of these processes applies in some situations.
Fortunately, the failure of one generally accepted approach to attitudes and persuasion to emerge over the last several decades has not inhibited the growth of a significant body of knowledge about attitude change processes. All of the approaches that we have described in this book have contributed significantly to this body of knowledge. Our goal in this chapter is to outline a general framework for thinking about attitude change processes that incorporates many of the major concepts discussed in the previous chapters of this book. As such, the framework takes one step toward a general theory of attitude change.
Even though all of the different approaches discussed in the previous chapters have different names, different postulates, and particular "effects" that they specialize in explaining, these different approaches can really be thought of as emphasizing two distinct routes to attitude change. The first route, which we call the central route, emphasizes the information that a person has about the attitude object or issue under consideration. Some of these central approaches focus on how the arguments in a persuasive message are comprehended and learned (see chap. 3); other central approaches focus on the information that people generate