**2.2. Social interdependence theory**

A second theory underlying cooperative learning is social interdependence theory [10]. In the early 1900s Kurt Koffka, proposed that groups were dynamic wholes in which the interdependence among members could vary. In the 1930s Kurt Lewin stated that the interdependence among members created by common goals is the essence of a group. The goal interdependence unites members into a "dynamic whole," so that changes in the state of a member or subgroup modify the state of other members or subgroups. In addition, motivation to accomplish the common goals results from an intrinsic state of tension within each group member. For interdependence to exist, there must be more than one person or entity involved, and the persons or entities must have dynamic impact on each other. In the late 1940s, Morton Deutsch, one of Lewin's graduate students, extended Lewin's reasoning about interdependence and formulated a theory of cooperation and competition [14, 15]. The authors of this chapter, David (who was a doctoral student of Deutsch) and Roger Johnson, extended and expanded Deutsch's theory [10, 13, 16–19]. It should be noted that the authors of this chapter (David and Roger Johnson) coined the term social interdependence theory to describe their expanded version of the theory of cooperative, competitive, and individualistic efforts. Deutsch believed that social interdependence theory included more than cooperative, competitive, and individualistic processes, so he reserved the term for a future yet undefined theory.

In his theory of cooperation and competition, Deutsch posits that cooperation is created by *positive goal interdependence*, which exists when group members perceive that they can reach their goals if and only if the other group members also reach their goals [14, 15]. Competition is created by *negative goal interdependence*, which exists when group members perceive that they can obtain their goals if and only if the other group members fail to obtain their goals. Individualistic efforts are creative by *no goal interdependence*, which exists when individuals perceive that reaching their goal is independent from other individuals attaining their goals.

Positive goal interdependence tends to result in promotive interaction, negative goal interdependence tends to result in oppositional interaction, and no goal interdependence results in an absence of interaction. The relationship between the cooperation and competition and the interaction pattern each elicits tends to be bidirectional. Each may cause the other.
