Natural Emotion Expression of a Robot Based on Reinforcer Intensity and Contingency

An emotional robot is regarded as being able to express its diverse emotions in response to internal or external events. This paper presents a robot affective system that is able to express life-like emotions. In order to do that, the overall architecture of our affective system is based on neuroscience from which we obtained the natural emotional processing routines. Based on that architecture, we apply the reinforcer effects expecting that those would lead the affective system to be more similar to real-life´s emotion expression. The robot affective system has responsibility for gathering environmental information and evaluating which environmental stimuli are rewarding or punishing. The emotion processing involves with appraisal of the external and internal stimuli, such as homeostasis, and generates the affective states of the robot. Therefore, emotions are associated with the presentation, omission, and termination of the expected rewards or punishers (reinforcers). The experimental results show that our affective system can express several emotions simultaneously as well as the emotions decrease, increase, or changes to another emotion seamlessly as time passes.