The face of trust: The effect of robot face ratio on consumer preference

As one of the latest applications in the era of artificial intelligence, a social robot is playing a more and more important role in our daily life. However, few attempts to date have been made to explore how robot facial appearance, particularly the facial width-to-height ratio (fWHR) and face shape of a robot, influence people's evaluation, such as perceived trustworthiness and purchase intention. Our study conducted a 2 (face shape) ^∗ 3 (fWHR) full factorial between-subject experiment to fill this research gap. 240 participants were recruited and randomly assigned to six scenarios in the study. After exposure to the stimuli, perceived trustworthiness and purchase intention were measured accordingly. Results suggested a counterintuitive phenomenon: unlike the effect of fWHR on human trustworthiness evaluation, high fWHR worked as a significant factor to improve robot trustworthiness and purchase intention. However, the effect of face shape and its interaction with fWHR did not significantly improve robot trustworthiness and purchase intention. In addition, the effect of fWHR on purchase intention was mediated by the robot trustworthiness. Theoretical and practical contributions are also discussed in this paper.