Designing Robot Embodiments for Social Interaction: Affordances Topple Realism and Aesthetics

In the near future, human-like social robots will become indispensable for providing support in various social tasks, in particular for healthcare (e.g., assistance, coaching). The perception of realism, in particular human-like features, can help facilitate mediated social interaction. The current study investigated the effects of form realism on engagement with and use intentions of social robot embodiments. We have defined (perceived) form realism as the result of the appraisal of features that are perceived as realistic contrasted with those appraised as unrealistic. To test the effects of form realism, we applied the model of interactively perceiving and experiencing fictional characters (I-PEFiC). I-PEFiC explains how users respond to interactive, fictional, humanoid characters, on social robots. In a within-subjects design, participants (N = 29; $$M_{age}$$Mage = 28.8  years, age range 18–56 years) interacted with three different robots built from LEGO Mindstorms, which differed in their degree of designed form realism. Each robot presented itself as a physiotherapy assistant and requested the participant to do several exercises. Results of a structured questionnaire indicated that form realism only played a modest role in the perception of electro-mechanical robots. Instead, the perception of affordances appeared to be crucial for determining engagement and intentions to use social robots.