The cowboy effect: robot gaze influences human decisions

In most everyday life situations, the brain needs to engage not only in making decisions, but also in anticipating and predicting the behavior of others. In such contexts, gaze can be highly informative about others intentions, goals and upcoming decisions. Here, we investigated whether a humanoid robots gaze (mutual or averted) influences the way people strategically reason in a social decisionmaking context. Specifically, participants played a strategic game with the robot iCub while we measured their behavior and neural (EEG) activity. Participants were slower to respond when iCub established mutual gaze prior to their decision, relative to averted gaze. This was associated with a higher decision threshold in the drift diffusion model and accompanied by more synchronized EEG alpha activity. In addition, we found that participants reasoned about the robots actions in both conditions. However, those who mostly experienced the averted gaze were more likely to adopt a self-oriented strategy and their neural activity showed higher sensitivity to outcome. Altogether, these findings suggest that robot gaze acts as a strong social signal for humans, modulating response times, decision threshold, neural synchronization, as well as choice strategies and sensitivity outcomes. This has strong implications for all contexts involving human-robot interaction, from robotics to clinical applications.