Effects of Size and Task Type on Group Performance and Member Reactions
Abstract
The effects of group size (2 through 7 members) and certain task characteristics (production, discussion, and problem solving type tasks) on group performance and member reactions were assessed. Subjects were students at two universities who performed three 15-minute tasks. Results showed that size had negligible effects on performance characteristics and strong effects on member reactions. Dyads tended to be most satisfied, and dissatisfaction increased in approximately linear fashion for larger groups. Type of task strongly affected both performance characteristics and member reactions. Contrary to expectations, there were no substantial interactions between size and task type in predicting member reactions or group performance. Several implications of the results were discussed: (a) the uniqueness of dyads in comparison to other groups sizes; (b) the question of what is the optimal group size; (c) the means by which the strong effects of task type may take place; and (d) questions raised by the finding that some substantial differences were obtained for subjects run at the two different universities. Many of the most obvious-and most potent-determiners of group behavior are, ironically enough, also among the least investigated and least understood in the group psychology field. Several reviewers (e.g., Golembiewski, 1962; Collins and Guetzkow, 1964; McGrath and Altman, 1966) have documented the dearth of systematic knowledge about two such factors: group size and the nature of the group task. Clearly, both group size and task characteristics should make differences in the ways people interact in groups and in the kinds of reactions they have to the group experience. The scattered empirical work which has in
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The suggested optimal group size to facilitate group discussion and performance is between 3 and 5.
“The suggested optimal group size to facilitate group discussion and performance has been proposed to be between 3 and 5 [30].”
From Mitigating cognitive biases in clinical decision-making through multi-agent conversations using large language models: simulation study (2024) · cites this paper as [30]
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“The suggested optimal group size to facilitate group discussion and performance has been proposed to be between 3 and 5 [30].”
- Authors
- Hackman, J. R., & Vidmar, N.
- Affiliations
- Yale University (US)
- Venue
- Sociometry
- Publisher
- JSTOR
- Published
- 1970-03
- Volume
- 33
- Issue
- 1
- Pages
- 37
- ISSN
- 0038-0431 (ISSN-L)
- OpenAlex
- W68630991
- Cited by
- 251
- References
- 18
- Citations by year
- 2026: 9 · 2025: 7 · 2024: 12 · 2023: 9 · 2022: 8 · 2021: 7 · 2020: 7 · 2019: 7 · 2018: 8 · 2017: 7 · 2016: 8 · 2015: 11 · 2014: 5 · 2013: 8 · 2012: 10
- FWCI
- 13.89
- Type
- journal article
- Language
- en
- Open access
- closed
- Locations
- Sociometry (publishedVersion)
- Topics
- Social Sciences › Psychology › Social Psychology › Team Dynamics and Performance
- Social Sciences › Sociology and Political Science › Social and Intergroup Psychology
- Social Sciences › Sociology and Political Science › Social Power and Status Dynamics
- Keywords
- group size, task type, group performance, group satisfaction, dyads, production tasks, problem-solving tasks, optimal group size, group interaction
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