Humanness lies in unpredictability: Role of Theory of Mind on anthropomorphism in human-computer interactions

Predictability is a core aspect of human-computer interaction (HCI), but an excess of predictability can lead to stereotypical behaviors and decreases the perceived agentivity (i.e., anthropomorphism) of a virtual agent. Yet, it remains unclear if inter-individual variability in predicting the behavior of other is modulating tendencies for anthropomorphism. The present study investigated the interaction between Theory of Mind (ToM) abilities and agent predictability and their association with anthropomorphism. Participants (N=38) completed self-reports of Perspective Taking capabilities and played the Matching Pennies Game with a virtual agent. The agent’s predictability was manipulated across four conditions, and participants reported their perception of the agent’s humanness and predictability. Results revealed that perceived predictability rather than self-reported Perspective Taking capabilities were positively associated with ToM abilities in predicting virtual agent’s behavior. However, increasing the virtual agent’s predictability decreased tendencies for anthropomorphism, stressing the role of randomness in perceiving humanness.