  Trust is a critical issue in Human Robot Interactions as it is the core of
human desire to accept and use a non human agent. Theory of Mind has been
defined as the ability to understand the beliefs and intentions of others that
may differ from one's own. Evidences in psychology and HRI suggest that trust
and Theory of Mind are interconnected and interdependent concepts, as the
decision to trust another agent must depend on our own representation of this
entity's actions, beliefs and intentions. However, very few works take Theory
of Mind of the robot into consideration while studying trust in HRI. In this
paper, we investigated whether the exposure to the Theory of Mind abilities of
a robot could affect humans' trust towards the robot. To this end, participants
played a Price Game with a humanoid robot that was presented having either low
level Theory of Mind or high level Theory of Mind. Specifically, the
participants were asked to accept the price evaluations on common objects
presented by the robot. The willingness of the participants to change their own
price judgement of the objects (i.e., accept the price the robot suggested) was
used as the main measurement of the trust towards the robot. Our experimental
results showed that robots possessing a high level of Theory of Mind abilities
were trusted more than the robots presented with low level Theory of Mind
skills.
