Towards understanding user preferences in robot-human handovers: How do we decide?

Service robots are expected to provide assistance to users by performing useful tasks, such as handing over objects upon request. Most robot-human handover studies implicitly assume that the handover action being executed is the same every time. We postulate that for real scenarios, however, a robot should be capable of accomplishing the handover task using multiple styles of handover, selecting the action that will most likely result in the successful execution of the task and the action that best accommodates different user preferences. This paper addresses the human aspect of this theory, investigating: (1) Will users prefer to have the robot execute more than one type of robot-human handovers? and (2) What factors do users take into account to favor one handover over another? In a survey realized with 62 participants from 2 different countries we conclude that not only is having more than one handover action important for the robot, but also identify 2 factors for selecting the best action autonomously.