Abstract

In the literature on group decision-making, there has been a paradoxical debate: some argue that groupness (e.g., conformity pressure) hampers group decision effectiveness, while others contend that commitment toward the group goal is a prerequisite of quality decision. According to the synergy model of individualism–collectivism (Choi, 2024), group effectiveness requires members to maintain self-independence against normative pressures while being strongly committed to group goals. Based on this framework, the present study proposes that a combination of personal agency belief and collectivistic value orientation enhances group decision effectiveness, because it simultaneously promotes independence in thinking and action and group goal commitment. We conducted an experiment involving fifty-four three-person discussion groups. Results showed that participants produced more effective arguments during the discussion when collectivistic value orientation was combined with personal agency belief compared to when combined with collective agency belief, suggesting a synergistic interaction between the two seemingly opposing constructs. Limitations of the study and future directions are discussed.