Smile mimicry smoothens human-virtual human interactions

During social interactions, people often unintentionally mimic each other's behaviors, which can occur at the motor level (e.g. smiles or head movements), and the autonomic level (e.g. pupil size). Mimicry has often been linked with increases in liking and trust and tends to smoothen the bond between interaction partners. However, people with social anxiety are generally less expressive and they may also have altered mimicry behavior. The current study aims to explore the relationship between mimicry, person-perception, and social anxiety levels by having participants interact with virtual humans. Compared to real interaction partners or photographed or filmed actors, virtual humans can be controlled and behaviors very precisely manipulated. Participants observed ten virtual humans telling a neutral story on a computer monitor. At predetermined time points, the virtual humans showed four types of expressions: smiles, head movements, pupil dilation, and blushing. After each story, we measured to what extent participants liked and trusted the virtual humans via the avatar evaluation questionnaire, the desire for future interaction scale, and an investment game. In addition, we assessed partic-ipants' social anxiety levels. The results show that participants, regardless of anxiety levels, mimicked the virtual humans' smiles and that smile mimicry is associated with an increased liking and trust toward the virtual humans. These results build on previous research showing that the mimicry of smiles acts as a social glue and also benefits virtual social interactions.