1. MOBOTS Group, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
2. LEARN, Center for Learning Sciences, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
3. Department of Computer Science, Universidad Rey Juan Carlos, Madrid, Spain
4. Computer Human Interaction in Learning and Instruction (CHILI) Laboratory, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland