Theory and Decision

, Volume 78, Issue 3, pp 357–376 | Cite as

Are individuals more risk and ambiguity averse in a group environment or alone? Results from an experimental study

  • Marielle Brunette
  • Laure Cabantous
  • Stéphane Couture


Most decision-making research in economics focuses on individual decisions. Yet, we know, from psychological research in particular, that individual preferences can be sensitive to social pressures. In this paper, we study the impact of a group environment on individual preferences for risky (i.e., known probabilities) and ambiguous (i.e., unknown probabilities) prospects. In our experiment, each participant was invited to make a series of lottery-choice decisions in two different conditions. In the Alone condition, individuals made private choices, whereas in the Group condition, individuals belonged to a three-person group and group members’ choices were aggregated according to either a majority or unanimity rule. This design allows us to study the impact of a group environment on individuals’ attitude towards both risky and ambiguous prospects, while controlling for the decision rule used in the group. Our experimental results show that when individuals are in the Group condition, they tend to be less risk averse and more ambiguity averse than when they are not part of a group (Alone condition). Our experiment also suggests that the decision rule matters as it shows that these two trends tend to be stronger when the group implements a unanimity rule. Specifically, we found that individuals who belong to a group implementing a unanimity rule are significantly less risk averse than individuals who belong to a group that relies on the majority rule. We obtained a similar—but non-significant—result under ambiguity.


Group Unanimity Majority Preferences Risk Ambiguity 



The authors would like to thank Youenn Lohéac, Julien Wolfersberger and the participants of the LAMETA seminar at Montpellier and the GAEL seminar at Grenoble.


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Copyright information

© Springer Science+Business Media New York 2014

Authors and Affiliations

  • Marielle Brunette
    • 1
  • Laure Cabantous
    • 2
  • Stéphane Couture
    • 3
  1. 1.INRANancyFrance
  2. 2.University of WarwickCoventryUK
  3. 3.UK INRA, Castanet-TolosanFrance

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