Gap the (Theory of) Mind: Sharing Beliefs About Teammates' Goals Boosts Collaboration Perception, Not Performance

Gap the (Theory of) Mind: Sharing Beliefs About Teammates' Goals Boosts Collaboration Perception, Not Performance Abstract --In human-agent teams, openly sharing goals is often assumed to enhance planning, collaboration, and effectiveness. However, direct communication of these goals is not always feasible, requiring teammates to infer their partner's intentions through actions. Building on this, we investigate whether an AI agent's ability to share its inferred understanding of a human teammate's goals can improve task performance and perceived collaboration. Through an experiment comparing three conditions--no recognition (NR), viable goals (VG), and viable goals on-demand (VGod)--we find that while goal-sharing information did not yield significant improvements in task performance or overall satisfaction scores, thematic analysis suggests that it supported strategic adaptations and subjective perceptions of collaboration. Cognitive load assessments revealed no additional burden across conditions, highlighting the challenge of balancing informativeness and simplicity in human-agent interactions. These findings highlight the nuanced trade-off of goal-sharing: while it fosters trust and enhances perceived collaboration, it can occasionally hinder objective performance gains. In human-agent collaboration, effective teamwork often depends on the agent's ability to interpret and act upon the human teammate's intentions. Ad-hoc teamwork [1], where team members must collaborate effectively without prior planning, exemplifies contexts where this capability is critical. Explainable AI (XAI) aims to address this by enhancing transparency and interpretability in AI systems, fostering shared mental models, trust, and mutual understanding [2], [3].