Task-irrelevant human and robot head movements bias gaze in humans who follow them through virtual reality.

In prolonged social interactions, human attention and gaze are profoundly influenced by the looking behavior of others - to an extent that gaze-based communication strategies have been transferred from human-human to human-robot collaboration. Much less is known as to how gaze-based interactions play out during encounters in (semi-)public spaces, when an agent encounters another agent without them interacting towards a common goal and without the other's gaze providing any information of relevance for the first agent's task. Here, we investigate such a situation. We asked participants to walk behind an avatar - human or robot - who proceeded at constant speed through corridors of a virtual-reality version of a university building. Corridors had posters on the side walls. In some corridors but not in others, the avatar looked at three different posters, either 3 on the same side or 2 on one side and 1 on the other. Although the avatars' looking behavior had no relevance for the participants, we found that participants' gaze in a corridor was biased to the side of the posters the avatar looked at, irrespective of avatar type (human or robot). This suggests that gaze following occurs even in situations where it has no apparent benefit.