Human-robot communication scenarios are becoming increasingly important. In this paper, we investigate the differences between human-human and human-robot communication in the context of persuasive communication. We ran an experiment using the door-in-the-face technique in a hu-manrobot context. In our experiment, participants communicated with a robot that performed the door-in-the-face technique, in which the communicating agent asks for an "extreme" favor first and a for a small favor shortly after to increase affirmative response to the second request. Our results show a surprisingly high acceptance rate for the extreme request and a smaller acceptance rate for the small request compared to the original study of Cialdini et al., so our results differ from the classical human-human door-in-the-face experiments. This suggests that human-robot persuasive communication differs from human-human communication, which is surprising given related work. We discuss potential reasons for our observations and outline the next research steps to answer the question whether the door-in-the-face and similar persuasive techniques would be effective if applied by robots. © 2023 Copyright for this paper by its authors.