Preliminary Exploration of Agent-Human Emotional Contagion via Static Expressions

In social psychology, emotional contagion describes the widely observed phenomenon of one person’s emotions mimicking surrounding people’s emotions [13]. While it has been observed in humanhuman interactions, no known studies have examined its existence in agent-human interactions. As virtual characters make their way into high-risk, high-impact applications such as psychotherapy and military training with increasing frequency, the emotional impact of the agents’ expressions must be accurately understood to avoid undesirable repercussions. In this paper, we perform a battery of experiments to explore the existence of agent-human emotional contagion. The first study is a between-subjects design, wherein subjects were shown an image of a character’s face with either a neutral or happy expression. Findings indicate that even a still image induces a very strong increase in self-reported happiness between Neutral and Happy conditions with all characters tested and, to our knowledge, is the first ever study explicitly showing emotional contagion from a virtual agent to a human. We also examine the effects of participant gender, participant ethnicity, character attractiveness, and perceived character happiness and find that only perceived character happiness has a substantial impact on emotional contagion. In a second study, we examine the effect of a virtual character’s presence in a strategic situation by presenting subjects with a modernized Stag Hunt game. Our experiments show that the contagion effect is substantially dampened and does not cause a consistent impact on behavior. A third study explores the impact of the strategic decision within the Stag Hunt and conducts the same experiment using a description of the same strategic situation with the decision already made. We find that the emotional impact returns again, particularly for women, implying that the contagion effect is substantially lessened in the presence of a strategic decision.