On the Role of Facial Width-to-Height Ratio of Humanoid Robots for Human-Robot Interactions

This research investigates consequences of robots’ facial shape in human-robot interactions. More precisely, we draw on a topic from social psychology – the facial width-to-height ratio (fWHR). As prior research shows, wider faces (i.e., faces with high fWHR) of both humans and nonhuman enti-ties are perceived as more dominant and physically imposing. Accordingly, we assume that individ-uals perceive humanoid robots with a higher fWHR (i.e., with a wider face) as more dominant than robots with lower fWHR (i.e., with a narrower face), resulting in increased compliance to recom-mendations given by robots with higher fWHR. An initial laboratory experiment revealed a signifi-cant relationship between robot’s fWHR and humans’ propensity to follow recommendations given by robots in such a way that humans tend to behave significantly more compliant to the recommen-dation given by a representation of a humanoid robot when the face of the robot has a high (vs. low) fWHR.