The Monty Hall problem is a well-known but difficult probabilistic inference task; however, its difficulty is not solely associated with the probabilistic calculation. This problem is concerned with social interaction between a participant and the character in the problem, Monty. A dialogue between the contestant (i.e., the participant) and the host can induce strategic thought in the participant. In this study, we examined how trust in the host affects the participants’ choice. Answers from 232 participants revealed that people tended to be more conservative (i.e., they did not choose to change the door) when they mistrusted the host, suggesting that this non-normative behavior may be a result of the participant’s defense against the host’s betrayal. However, it has become clear that further examination is needed into information regarding the credibility of the host interacting with the participant.
