Outcome evaluations in group decision making using the majority rule: An electrophysiological study

Authors

  • Kenta Kimura,

    Corresponding author
    1. Center for Applied Psychological Science, Kwansei Gakuin University, Nishinomiya, Japan
    • Address correspondence to: Kenta Kimura, Center for Applied Psychological Science, Kwansei Gakuin University, 1-155, Uegahara Ichiban-cho, Nishinomiya, Hyogo, 662 8501, Japan. E-mail: kkimura@kwansei.ac.jp

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  • Jun'ichi Katayama

    1. Center for Applied Psychological Science, Kwansei Gakuin University, Nishinomiya, Japan
    2. Department of Psychological Science, Kwansei Gakuin University, Nishinomiya, Japan
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  • This work was supported by MEXT (The Ministry of Education, Culture, Sports, Science and Technology, Japan)—Supported program for the Strategic Research Foundation at Private Universities (2010-2014) to the Center for Applied Psychological Science (CAPS), Kwansei Gakuin University.

Abstract

Event-related brain potential (ERP) reflecting outcome evaluation is called feedback-related negativity (FRN). The present study examined the evaluative processes for two different types of outcomes by recording ERPs from three participants during a group decision task. First, we examined the evaluative processing of outcomes associated with group decisions using the majority rule. Second, we investigated whether the majority rule influenced the evaluation of conflicts related to individual opinions among group members. We found that FRN for monetary loss associated with the group decision was reduced when the participant's opinion was in the minority. In addition, conflict of opinions among group members elicited FRN-like negativity, and greater amplitudes were observed when the participant's opinion was in the minority. The present results suggested that the majority rule can modulate outcome evaluations in group decision making.

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