Project Information

Kurt Lewin Instituut
Heidelberglaan 1
Room Number H1.42
The Netherlands
T: +31 (0)30 - 253 3027

Project Information

Project Title
"Group size and cooperation"

VU University Amsterdam - Social and Organizational Psychology

PhD Student
Leonard Peperkoorn

Dr. Daniel Balliet (VU University Amsterdam)
Prof.dr. Paul van Lange (VU University Amsterdam)

1 July 2015 - 30 June 2019

VU University Amsterdam


While humans evolved in small-scale kin-based groups, modern societies tend to contain larger groups. Despite its relevance, it is unclear what group size is the most appropriate for human cooperation. For over several decades, researchers have proposed that group efficiency and cooperation would decrease as the size of the group increases. Yet, past research has showed somewhat inconsistent findings on how group size affects cooperation. In the present project we will employ meta-analytic techniques to review papers that manipulated group size and measured cooperation in several economic games, especially social dilemmas (e.g., N-person prisoner’s dilemma, commons dilemma, volunteer’s dilemma, public goods dilemma). In addition, we will run experimental studies on group size in daily life (e.g., what number of persons are preferred for daily activities such as working together on a common assignment; what number of persons are actually present in such situations). Finally, in order to arrive at effective interventions with the aim to increase cooperative behavior in applied settings it would be important to map the situational characteristics for theoretically relevant group size configurations. The completion of this research endeavor will allow us to discuss the broader implications for theory and research on group size.

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