Evolving Expression of Emotions Through Color in Virtual Humans Using Genetic Algorithms

For centuries artists have been exploring the formal elements of art (lines, space, mass, light, color, sound, etc.) to express emotions. This paper takes this insight to explore new forms of expression for virtual humans which go beyond the usual bodily, facial and vocal expression channels. In particular, the paper focuses on how to use color to influence the perception of emotions in virtual humans. First, a lighting model and filters are used to manipulate color. Next, an evolutionary model, based on genetic algorithms, is developed to learn novel associations between emotions and color. An experiment is then conducted where non-experts evolve mappings for joy and sadness, without being aware that genetic algorithms are used. In a second experiment, the mappings are analyzed with respect to its features and how general they are. Results indicate that the average fitness increases with each new generation, thus suggesting that people are succeeding in creating novel and useful mappings for the emotions. Moreover, the results show consistent differences between the evolved images of joy and the evolved images of sadness.