Information integration theory (IIT) seeks to develop a unified theory of judgment and behavior. This theory provides a conceptual framework that has been applied to a variety of research areas including personality impression formation and decision making. In these applications information integration theory has helped to resolve methodological and theoretical problems. The core of the IIT approach lies in the inductive analysis of multiple causation. IIT is applied in an inductive mode; generalizations emerge from experimental analysis. In nearly every area in which integration theory has been applied, this focus has led to significant restructuring of basic issues. This shift in thinking affects every aspect of research, from mundane details of methodology to the epistemological nature of theory. Moreover, the inductive perspective sees behavioral science not as a formalized knowledge structure, but as an ongoing inquiry system. For IIT, the ultimate unit of analysis is the individual. The IIT approach has implications for various types of generality and for nomothetic versus ideographic research strategies. (Author/ABL)