Theory of Mind (ToM) on Robots: A Neuroimaging Study

Theory of Mind (ToM) is not only a key capability for cognitive development but also for successful social interaction. In order for a robot to interact successfully with a human both interaction part- ners need to have an adequate representation of the other’s actions. In this paper we address the question of how a robot’s actions are perceived and represented in a human subject interacting with the robot and how this perception is influenced by the appearance of the robot. We present the preliminary results of an fMRI-study in which participants had to play a version of the classical Prisoners’ Dilemma Game (PDG) against four opponents: a human partner (HP), an anthropomorphic robot (AR), a functional robot (FR), and a computer (CP). The PDG scenario enables to implicitly measure mentalizing or Theory of Mind (ToM) abilities, a technique com- monly applied in functional imaging. As the responses of each game partner were randomized unknowingly to the participants, the attribution of intention or will to an opponent (i.e. HP, AR, FR or CP) was based purely on differences in the perception of shape and embodiment. The present study is the first to apply functional neuroimaging methods to study human-robot interaction on a higher cognitive level such as ToM. We hypothesize that the degree of anthropomor- phism and embodiment of the game partner will modulate cortical activity in previously detected ToM networks as the medial pre- frontal lobe and anterior cingulate cortex.