The hesitation of a robot: A delay in its motion increases learning efficiency and impresses humans as teachable

If robots learn new actions through human-robot interaction, it is important that the robots can utilize rewards as well as instructions to reduce humans´ efforts. Additionally, ¿interval¿ which allows humans to give instructions and evaluations is also important. We hence focused on ¿delays in initiating actions¿ and changed them according to the progress of learning: long delays at early stages, and short at later stages. We compared the proposed varying delay with a constant delay by an experiment. The result demonstrated that the varying delay improves learning efficiency significantly and impresses humans as teachable.