When a Robot Violates Expectations

In an experimental lab study with a 2x2 between-subjects-design (N = 162), the aim was to examine how a negative expectancy violation caused by a social robot and its reward valence, which represents how desirable it is to interact with this robot, affect the evaluation of the robot and the interaction with it. The negative expectancy violation led to less positive evaluations of the interaction with the robot as well as its sociability and competence. The robot with a high reward valence evoked a more positive evaluation of the interaction with it as well as its sociability. Furthermore, when the robot had a low reward valence, an expectancy violation led participants to increasingly rate the robot's behavior as deviating from what they expected.