2026 Theses Doctoral

Team Decision Making: Understanding How Verbal Reasoning and Non-Verbal Network Support and Obstruction Mechanisms Impact Group Decisions

Mah, Elisabeth

Group decision making is a critical function in organizations. Group participation in decisions is thought to help improve outcomes because of pooled information sharing and accountability to mitigate decision errors. Despite such benefits, there are still many challenges to group decision processes that make it difficult to reap the rewards of group discourse that relate to both individual and group-level factors. In particular, very little research explains how complex reasoning and network support dynamics in groups impact decision-making outcomes.

Thus, the present study integrates Behavioral Reasoning Theory (BRT), a decision and reasoning-grounded framework, with Dynamic Network Theory (DNT), an interpersonal dynamic framework, to identify how group-member interactions in decision discourse affect individual reasoning and final choice outcomes. This integrative approach uniquely provided a means of tracing the internal and overt reasoning in a working group as well as their observable supportive or non-supportive network relations in the decision discussions. This approach enabled a precise root-cause analysis of the individual and social factors related to final choice outcomes.

Three key sets of hypotheses were examined: 1) the effect of individual private reasoning on final vote outcome, 2) the effect of ego reasoning vs. alter reasoning on final vote outcome, and 3) the effect of ego support behaviors vs. alter support behaviors on final vote outcomes. Individuals (N=71) completed an individual reasoning survey prior to group deliberation. Multilevel modeling was conducted across groups (N=16 groups with four to six members in each) to account for both individual and compositional group-level variables.

Results showed that ego group reasoning and ego group supportive behaviors toward others’ dialogue (e.g., head nodding toward others’ reasons) significantly predicted ego’s final vote above and beyond private individual reasoning. Furthermore, while alter reasoning was marginally significant in predicting ego’s final vote, alter support (e.g., head nodding toward ego’s reasoning from others) was not found to be significant, suggesting the relative importance of public reason discussion in forming group decisions. Implications for researchers and practitioners are discussed.