Embodied conversational agents (ECAs) are paradigms of conversational user interfaces in the form of embodied characters. While ECAs offer various manipulable features, this paper focuses on a study conducted to explore two distinct levels of presentation realism. The two agent versions are photorealistic and animated. The study aims to provide insights and design suggestions for speech-enabled ECAs within serious game environments. A within-subjects, two-by-two factorial design was employed for this research with a cohort of 36 participants balanced for gender. The results showed that both the photorealistic and the animated versions were perceived as highly usable, with overall mean scores of 5.76 and 5.71, respectively. However, 69.4 per cent of the participants stated they preferred the photorealistic version, 25 per cent stated they preferred the animated version and 5.6 per cent had no stated preference. The photorealistic agents were perceived as more realistic and human-like, while the animated characters made the task feel more like a game. Even though the agents' realism had no significant effect on usability, it positively influenced participants' perceptions of the agent. This research aims to lay the groundwork for future studies on ECA realism's impact in serious games across diverse contexts.

翻译：具身对话代理（ECAs）是以具身化角色为形式的对话用户界面范式。尽管ECAs提供多种可操作特征，本文聚焦于一项探索两种不同呈现真实度水平的研究。两种代理版本分别为照片写实风格与动画风格。本研究旨在为严肃游戏环境中支持语音交互的ECAs提供见解与设计建议。采用被试内两因素析因设计，共36名性别均衡的参与者参与实验。结果显示，照片写实版本与动画版本均被感知为高度可用，整体平均分分别为5.76和5.71。然而，69.4%的参与者表示偏好照片写实版本，25%偏好动画版本，5.6%未明确偏好。照片写实代理被感知为更真实且更具人类特征，而动画角色使任务更具游戏感。尽管代理真实度对可用性无显著影响，但其对参与者对代理的感知产生了积极影响。本研究旨在为后续探索不同情境下严肃游戏中ECA真实度影响的研究奠定基础。