I'm Your Partner - I'm Your Boss

Using speech as an effective communication modality in human-robot interaction (HRI) allows designers to implement conceptual metaphors as a linguistic device. Metaphors appear to instantiate psychological framing effects and can influence the user´s reasoning significantly. The present paper presents two consecutive studies that explore how metaphors can be used in speech output for social robots to deliberately influence the user's perception of their relationship with the robot. As a first step, metaphoric expressions for framing cooperation or delegation in HRI settings were identified in a workshop. Effects of those metaphors on people´s strategies for organizing tasks in human-robot collaboration were then evaluated in an online survey. We found that metaphors suitable for encouraging users to do a task together with a robot are metaphors like "partners on a journey" or "allies". In contrast, metaphors that can be used to encourage handing over the task to a robot are metaphors like "boss" or "ruler". Further research needs to test whether these metaphors also have an effect on users' actions in HRI settings.