Contextual Emotion Appraisal Based on a Sentential Cognitive System for Robots

Emotion plays a powerful role in human interaction with robots. In order to express more human-friendly emotions, robots need the capability of contextual appraisal that expresses the emotional relevance of various targets in the spatiotemporal situation. In this paper, an emotional appraisal methodology is proposed to cope with such contexts. Specifically, the Ortony, Clore, and Collins model is abstracted and simplified to approximate an emotional appraisal model in the form of a sentence-based cognitive system. The contextual emotion appraisal is modeled by formulating the emotional relationships among multiple targets and the emotional transition with events and time passing. To verify the proposed robotic system’s feasibility, simulations were conducted for scenarios where it interacts with humans manipulating liked or disliked objects on a table. This experiment demonstrated that the robot’s emotion could change over time like humans by using a proposed formula for emotional valence, which is moderated by emotion appraisal of occurring events.