Robot facial expressions and gaze are important factors for enhancing human-robot interaction (HRI), but their effects on human collaboration and perception are not well understood, for instance, in collaborative game scenarios. In this study, we designed a collaborative triadic HRI game scenario, where two participants worked together to insert objects into a shape sorter. One participant assumed the role of a guide. The guide instructed the other participant, who played the role of an actor, by placing occluded objects into the sorter. A humanoid robot issued instructions, observed the interaction, and displayed social cues to elicit changes in the two participants' behavior. We measured human collaboration as a function of task completion time and the participants' perceptions of the robot by rating its behavior as intelligent or random. Participants also evaluated the robot by filling out the Godspeed questionnaire. We found that human collaboration was higher when the robot displayed a happy facial expression at the beginning of the game compared to a neutral facial expression. We also found that participants perceived the robot as more intelligent when it displayed a positive facial expression at the end of the game. The robot's behavior was also perceived as intelligent when directing its gaze toward the guide at the beginning of the interaction, not the actor. These findings provide insights into how robot facial expressions and gaze influence human behavior and perception in collaboration.

翻译：机器人面部表情和注视是增强人机交互的重要因素，但其对人类协作与感知的影响在协作游戏场景中尚未得到充分理解。本研究设计了一个三方协作人机交互游戏场景，两名参与者共同将物体插入形状分类器。其中一名参与者担任指导者角色，指导另一名扮演执行者的参与者，通过将遮挡的物体放入分类器来完成操作。一台人形机器人发出指令、观察互动，并通过社交信号引导两名参与者的行为变化。我们以任务完成时间衡量人类协作效率，同时通过参与者对机器人行为（智能或随机）的评分来评估其感知。参与者还通过填写Godspeed问卷对机器人进行评价。研究发现，与中性面部表情相比，机器人游戏开始时展现快乐表情时，人类协作效率更高。此外，当机器人在游戏结束时表现出积极面部表情时，参与者认为其更具智能性。若机器人互动初期将注视投向指导者而非执行者，其行为也被感知为智能。这些发现揭示了机器人面部表情与注视如何影响协作中的人类行为与感知。