This article describes part of the common ground on which behavior analysts and social psychologists can meet for fruitful discussions to further their research: Both groups of investigators share an interest in rule-governed behavior. I describe four lively research areas of mainstream social psychology to illustrate that shared interest-time horizons , optimism and pessimism, attribution, and equity theory. Numerous experiments in each area are designed to (a) discover individuals' self-rules and (b) analyze their implications for various activities in daily life.For some time now, behavior analysts have been admonished to cooperate with researchers in other fields (e.g., Czubaroff, 1993;Glenn, 1993). If such efforts are to be successful , it is essential to find common grounds for mutually useful dialogues. In this article I outline a shared interest that can bring behavior analysts and social psychologists together. Because researchers in different fields belong to separate verbal communities, shared interests are often obscured by specialized concepts and procedures. But when we pierce the verbal thickets, we discover an excellent example of common ground: rule-governed behavior.In recent years, behavior analysts have paid increasing attention to rule-governed behavior, and by now the analysis of rule-governed behavior is as useful as the study of contingency-shaped behavior has always been (e.g. , Baum, 1995;Hayes, 1989;Malott, 1989; Zettle, 1990). On the following pages, I suggest that a considerable portion of experimental and theoretical work in contemporary mainstream social psychology is also concerned with rule-governed behavior, even though that term is not used. I intend to show that effective cooperation of behavior analysts and social psychologists is made possible by their shared interest in rule-governed behavior, and that together they contribute to a better understanding of the activities that constitute daily life.