Investigating Perceived Task Urgency as Justification for Dominant Robot Behaviour

For the ubiquitous application of mobile robots, robots will need strategies to efficiently navigate through spaces shared with humans. To accomplish time-critical tasks, it can be necessary for robots to take precedence over humans. Giving a justification for such dominant robot behaviour, based on the urgency of its task, might mitigate negative effects on trust and acceptance and enhance behavioural compliance by waiting for the robot to pass. This study investigates the perceived urgency of different tasks a robot might perform. Therefore, 129 participants rated and compared ten tasks in an online study. The results reveal differences in perceived task urgency, related to time pressure in accomplishing the task. Differences in task urgency also affected the choice of who should be given priority to precede in a spatial conflict (human or robot). Furthermore, the results indicate a bias around human-robot interactions: Priority was more often granted to the human than the robot, when equally urgent tasks were presented for both entities.