The Design and Development of a Goal-Oriented Framework for Emotional Virtual Humans

Affective interaction with virtual humans can enhance the quality of user experience in virtual reality. It takes place through various considerations such as emotional representation in their behavioral patterns, facial expressions, head pose, body stance, and so on. Deciding on the emotional state of a virtual human at a moment, however, is still a challenge. Computational models of emotion, stemming from appraisal theories, are suggested for modeling emotion in virtual agents. Despite their competence in extracting emotion from appraisal values, they are poorly defined in describing how to assess appraisal values within a sense-think-act behavior model. Motivated by this lack of empirical knowledge on the appraisal stage, in this preliminary work, we propose a framework to bridge the gap between a computational model of emotion and a behavior model of virtual humans. To this end, we use a need-based, goal- oriented, autonomous behavior model to generate salient stimuli for eliciting emotions. Our simulation of a case study suggests that the proposed framework can produce sensible emotional states that conform to the essential principles of appraisal-based emotion theories.