# The Impact of an Agent's Voice in Psychological Counseling: Session Evaluation and Counselor Rating
## 1 Introduction  
The emergence of artificial intelligence (AI) has diversified communication methods between computers and humans. [PERSON] [1] stated that a need for a paradigm shift from computer-mediated communication to human-machine communication arose with the advent of intelligent machines. In accordance with the advancement of AI, an increasing number of discussions have been recently conducted to apply AI technology in psychological counseling. A psychological counseling system using an AI-based conversational agent (CA) can provide various solutions for overcoming the limitations of existing counseling systems. Counseling systems based on a CA do not suffer from fatigue and emotional exhaustion, etc., like that of a human counselor. People also found it easier to show their emotions objectively with less fear and pressure when communicating with a CA [2, 3]. Thus, AI application in psychological counseling can be said to be an adequate field of study in the sense that AI development aims to achieve automated interactions through human-machine communication [4].  
Voice provides the listener with several information about the speaker, such as its gender [5], emotional conditions, and personality [6]. It is an essential medium for human communication and a social interaction technique that people use to determine the impression and likeability of another person [7]. Upon hearing of an unacquainted voice, people automatically form the first impression of the personality of the speaker and infer traits such as trustworthiness, attractiveness, etc., of the said speaker [8, 9, 10, 11]. Such first impressions based on the speaker's voice are formed very swiftly and remain consistent [10, 12]. [PERSON] [13] found that the perception of users toward an agent varied according to the intonation of such agent. Likewise, the voice of the voice-based CA which delivers amessage plays an extremely significant role in building a relationship between the agent and its user in a human-AI communication.  
Clinical counseling research shows that the effectiveness of counseling is dependent on the counselor rather than on theoretical differences, and the characteristics of the counselor is a significant element of clinical counseling therapies [14; 15]. [PERSON] [16], performing a meta-analysis on 141 studies, addressed in his study the characteristics of the counselor which affect the outcome of counseling that observable traits of the counselor such as gender, age, and ethnicity affect the outcome of counseling. Particularly, people automatically infer traits of the agent based on its voice and such inferred traits of the agent affect the attitude and contents of the conversation between the agent and its users [17; 18; 19]. People arbitrarily interpret the persona of the CA based on its voice and such interpretation of persona affect their response to and perception of the CA [20]. Therefore, the perception of users towards the agent is crucial in the fields of eHealth, including psychological counseling [21]. As the voice of the agent exerts considerable effects on the perception of users, it should be designed with full consideration of social aspects and conversational context. However, research on human-robot interaction (HRI) related to the voice of the agent has received less attention than that on functions of robots and improvement in their linguistic abilities. Thus, this study examined the effects of the agent's voice on the perception of users toward the agent and the counseling effects.