ORGANIZATIONAL BEHAVIOR AND HUMAN DECISION PROCESSES Vol. 73, Nos. 2/3, February/March, pp. 142–162, 1998 ARTICLE NO. OB982759 Group Dynamics in Janis’s Theory of Groupthink: Backward and Forward Clark McCauley Bryn Mawr College Janis’s groupthink theory is an appealing explanation of how group process can get in the way of optimal decision making. Unfortunately, Janis was selective and not always consistent in his application of research in group dynamics. This paper traces groupthink to its theoretical roots in order to suggest how a broader and more consistent use of research in group dynamics can advance understanding of decision-making problems. In par- ticular, the paper explores and reinterprets the groupthink pre- diction that poor decision making is most likely when group cohe- sion is based on the personal attractiveness of group members.  1998 Academic Press Groupthink (Janis, 1972, 1982) is a theory of how group dynamics can get in the way of effective decision making. The success of the groupthink formulation seems to have turned attention away from its origins in group dynamics re- search, and in this paper I look backward to clarify these origins and forward to highlight more recent research that may help improve group decision making. I begin with a brief summary of groupthink predictions and the normative model of decision making implied by these predictions. Then I examine the origins and limitations of Janis’s use of group dynamics research and try to show how a broader and updated view of group dynamics can amplify our understanding of how group decisions go awry. Finally, I offer my own opinion about why groupthink has been so popular a conception, despite its problems, and about how Janis’s work should inspire future research. I acknowledge at the outset my own parochial limitations as a social psycholo- gist; I am not able to integrate in this paper the burgeoning literature on group performance in relation to issues of management and organization (e.g., I owe thanks for comments and suggestions toward improving this paper to Albert Pepitone, Marlene Turner, Anthony Pratkanis, and four expert but anonymous reviewers. Address reprint requests and correspondence to ClarkMcCauley, Psychology, Bryn Mawr College, Bryn Mawr, PA 19010. Fax: (610) 526-7476. E-mail: cmccaule@brynmawr.edu. 142 0749-5978/98 $25.00 Copyright  1998 by Academic Press All rights of reproduction in any form reserved.