  This study investigates how different virtual agent (VA) behaviors influence
subjects' perceptions and group decision-making. Participants carried out
experimental group discussions with a VA exhibiting varying levels of
engagement and affective behavior. Engagement refers to the VA's focus on the
group task, whereas affective behavior reflects the VA's emotional state. The
findings revealed that VA's engagements effectively captured participants'
attention even in the group setting and enhanced group synergy, thereby
facilitating more in-depth discussion and producing better consensus. On the
other hand, VA's affective behavior negatively affected the perceived social
presence and trustworthiness. Consequently, in the context of group discussion,
participants preferred the engaged and non-affective VA to the non-engaged and
affective VA. The study provides valuable insights for improving the VA's
behavioral design as a team member for collaborative tasks.
