Effect of a Virtual Agent's Appearance and Voice on Uncanny Valley and Trust in Human-Agent Collaboration

Anthropomorphic agents are generally evaluated more positively and trustworthy by human users than agents that are not humanlike. However, subtle mismatches in an agent’s appearance and behavior can lead to perceived uncanniness resulting in a disrupted trust during human-agent interaction. This study investigated the impact of an agent’s appearance and voice mismatch on user perception of the agent and their level of trust during a collaborative decision-making task. In a 2×2 between-subjects experimental design, participants performed an emotion recognition task while receiving recommendations from a virtual agent that either had a humanlike or robotic appearance with either a humanlike or synthesized robotic voice (4 conditions). Trust was measured both subjectively using a questionnaire and behaviorally by evaluating participants’ conformity to the agent’s input in their final decision-making. Results indicated that while the agent’s voice-appearance mismatch affected participants’ perception of anthropomorphism, it was not an influential factor in people’s trusting behavior. We discuss these results in the context of task complexity and make recommendations for future research.