Effect of AI counsellor’s nonverbal immediacy behaviour on user satisfaction: serial mediation of positive expectancy violation and rapport

The aim of this study is to verify the causal relationship between the nonverbal immediacy behaviour (NIB) of an artificial intelligence (AI) agent for mental health counselling and user satisfaction through an experiment. We explored whether the anthropomorphism of the AI agent moderated the effect of the AI agent. A 2 (NIB: absent vs. present) × 2 (anthropomorphism: low vs. high) between-subjects experiment was conducted. The participants answered questionnaires after having a conversation about their daily stress with an AI counsellor, which was implemented according to the experimental conditions in the metaverse counselling room. The results showed that the NIB of the AI agent had a positive effect on user satisfaction, which was serially mediated by positive expectancy violations and rapport. However, anthropomorphism was not found to moderate the effects of NIB on user satisfaction. This study contributed to theoretical elaboration by providing empirical evidence that the effect of NIB is significant in AI counselling and by revealing that this effect occurs through a serial mediation path of positive expectation violation and rapport.