Group cognition, membership change, and performance: Investigating the benefits and detriments of collective knowledge

This study analyzes the effects of group membership change on group cognition and performance to determine how groups can simultaneously leverage oldtimers' collective knowledge and a newcomer's expertise. Our analysis focuses specifically on the interrelated effects of the two components of a transactive memory system (TMS)-TMS structure and TMS processes-to explain the cognitive mechanisms through which membership change affects group performance. Results from a laboratory study show that groups that experience partial membership change tend to rely on the TMS structure that oldtimers developed in their original group, and that doing so is ultimately detrimental to performance because it creates inefficient TMS processes. Results from a supplemental study indicate that these TMS process inefficiencies can be avoided when oldtimers are instructed to reflect upon their collective knowledge prior to task execution. We discuss the implications for managing group cognition in organizations where membership change is prevalent. (c) 2007 Elsevier Inc. All rights reserved.