Many human activities are performed in groups---making decisions in workplace meetings, cooperating on a sports team, or meeting with friends for dinner. All these activities involve complex conditions and interaction processes that influence their outcomes in terms of performance, personal goals, and group objectives. As robots are increasingly being positioned within groups, improving these outcomes has emerged as an important application area in social robotics, particularly through robotic facilitation. Robot facilitators aim to elicit positive changes by deliberately influencing group processes. While research in this field has demonstrated that robots can effectively influence interpersonal dynamics, there remains a notable gap in consolidating these insights into a coherent understanding that can guide the design and development of better facilitators. 

We present a scoping review of literature targeting changes in interactions between multiple humans that are driven by intentional actions from robotic agents. To identify key considerations for the design of robot facilitators, we take inspiration from human group research theories to organize existing approaches. Our review includes 108 publications that meet our inclusion criteria, yielding 85 distinct application targets for group facilitation using robots. Based on the identified instances, we extract categories of possible application targets and a set of design concepts that can guide future work on robotic group facilitators.