How does group size affect group member trust and cohesion? In unstructured task groups, cohesion and performance begin to decline when the group has taken on too many members. Yet group size can also be an advantage, because it adds diverse skill sets to groups working on shared tasks. As group size increases, the problem of coordination often results in bureaucracy, which in turn can create new problems for effective collaboration. Investigating the maximum number of members for effective, unstructured task groups is important for understanding both how teams work together to achieve goals and how bureaucracy becomes attractive as a strategy for solving problems of collaboration.

This project examines how the maximum effective size of unstructured task groups is affected by the degree to which individual contributions are central to task completion, a phenomenon known as "task jointness." The study involves a set of laboratory experiments involving face-to-face groups, in which group size and task jointness are systematically varied. The following hypotheses derived from social psychological theory are tested: 1) Members of groups working on joint tasks will report higher trust than members of groups working on additive tasks and members of groups having a purely social interaction. 2) Groups with seven and eight persons working on joint tasks will report higher trust and cohesion than similar groups working on additive tasks, or than groups engaging in purely social interaction. 3) Members of groups working on joint tasks will be less likely to choose to leave their group as group size increases than members of additive task groups or purely social groups.

Broader Impacts The results of this study on the determinants of effective team work are of interest to people in business and complex organizations, both in the profit and non-profit and governmental sectors. Results seek to inform organizational design, as well as workflow and related workplace activities. Research will be conducted at a nationally known center for small-group research. The study will generate experimental and qualitative data that can serve as the basis for future research, theory development, and graduate student training in data analysis. The P.I.s will train undergraduate researchers in experimental methods, data collection, and analysis. Results will be disseminated at a multi-disciplinary conference on small-group research and prepared for publication in an appropriate academic journal.

Project Report

INTELLECTUAL MERIT: This research investigated the relationship between group size and the process of trust, cohesion, and commitment formation in joint-task groups. Specifically, the theory proposes that groups with greater six members will produce lower trust, cohesion, and commitment than those smaller than six members. Theory was developed linking group size to these processes through the mechanism of anticipated mutual perception, the amount an individual considers what others are thinking about them. Two experimental studies tested the impact of anticipated mutual perception on interpersonal influence and trust, cohesion, and commitment to work groups. Study 1 tested the impact of being able to see a partner and closeness to a partner on a partner’s level of influence over participants. Participants were more influenced by partners they could see than by partner’s who were separated from the participant by place or time. Differences between participants and their partners on expected task ability also affected influence, even when partners were absent, having left information for use by participants. Study 2 investigated how group size affected participant reports of interpersonal trust, cohesion, and commitment to other group members. Results suggest that members of larger groups had lower commitment to other group members, and that groups larger than six members were negatively associated with levels of trust reported by group members. Further, measures used to isolate aspects of anticipated mutual perception were shown to affect the development of interpersonal trust, cohesion, and commitment, in support of the theory. Group cohesion was found to vary with expectations of competence. These expectations significantly predicted measures capturing aspects of anticipated mutual perception, possibly offsetting negative effects of increasing group size. Study 2 also found evidence that group members prefer to work with groups made up of 4-6 members, consistent with the theory. This research has implications for the ways in which organizations design work groups to be effective. This research suggests that the size of the group as well as the characteristics of individuals and their partners may affect how people form cohesive relationships. Trust is an important aspect of groups that promotes cooperation, commitment, and the sense that one belongs and can contribute effectively. Further, this research supports a growing literature on the ways that personal interactions in work groups promote commitment to organizations. BROADER IMPACT AND PROJECT OUTCOMES: Research was conducted at a nationally known center for small group research for the purposes of involving the graduate student principal investigator. in training undergraduate researchers in experimental methods, data collection, and analysis. Four research assistants gained experience in handling data, running experimental research sessions, and data analysis techniques. One research assistant is now a graduate student at a research intensive university. The other three students are in the process of applying for admission to graduate programs in Sociology. From August 2011 to November 2012, this grant has supported research activities and provided compensation for 140 research participants. The research resulted in a dissertation completed on November 28, 2012. Further, parts of this research were presented at a multi-disciplinary conference on small group research in August 2011 and are being prepared for publication in an appropriate academic journal. The results speak directly to people who seek to design and manage work groups within organizations, as well as those who design communication media for business and collaboration at a distance.

National Science Foundation (NSF)
Division of Social and Economic Sciences (SES)
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Saylor Breckenridge
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University of Iowa
Iowa City
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