Influences of Language Expressions in Group Decision Making: Exploring Verbal Probability Expressions in Group Discussions with Conversational Agents

This study examined how verbal probability expressions (VPEs) used in group decision-making discussions influence individuals' decision-making processes. An online experimental task was developed to investigate how biased decisions emerge depending on the type of expression used during discussions. Scripted conversational agents were employed to experimentally manipulate the VPEs used during group discussions. 440 participants took part in the online experiment, which controlled two factors: (1) the type of VPEs used by group members during discussions and (2) the type of anchoring group decision. The results revealed an interaction between these two factors when participants perceived the agents as human-like. Specifically, confirmation bias occurred more quickly when positive VPEs were used by the agents and the anchoring probability of the group decision was low (20\%). These findings provide valuable insights into the influence of VPEs on probability decision-making during group discussions, highlighting the advantages of utilizing multiple conversational agents for investigation.