The general long term objectives of the research program are to study how the need for cognitive closure affects major aspects of group process in ways reflecting the evolution of a conservative attitude among the group members. More specifically, the following issues of interest will be investigated: I. Whether group members' need for closure affects the preferred type of leadership and decision-making rules. II. Whether group members' need for closure affects the status-allocation processes within the group. III. Whether group members' need for closure affects how it deals with change (in specific reference to membership-shifts and variation in group- tasks). IV. Whether group members' need for closure affects intra-group relations, in particular those between a minority and the-majority. V. Whether group members' need for closure affects inter-group relations, in particular those with outgroup vs. ingroup members. All the above issues bear on major ways in which individuals function in groups. Understanding those matters may have important health consequences both in terms of improving individuals' adjustment to groups, their ability to optimally function in groups and the ability of groups to optimally contribute to individuals' welfare. Altogether fifteen studies are proposed designed to allow convergent validation of the central theoretical notions through multiple operationalizations of the need for closure.