Before revision:  In such cases, reinforcement learning arises naturally since the interaction is a key component in both reinforcement learning and social robotics . This article surveys reinforcement learning approaches in social robotics. We propose a taxonomy that categorizes reinforcement learning methods in social robotics according to the nature of the reward function.
After revision:  In such cases, reinforcement learning arises naturally since the interaction is a key component in both reinforcement learning and social robotics , it can be a well-suited approach for real-world interactions with physically embodied social robots. The scope of the paper is focused particularly on studies that include social physical robots and real-world human-robot interactions with users. In addition to a survey, we categorize existent RL approaches based on the design of the reward function.