Characters that display emotion are critical to a rich and believable simulated environment, especially when those characters interact with real people possessing real emotions. Emotion is the essential element that creates the difference between robotic behavior and lifelike, engaging behavior. Traditionally, animators have painstakingly created these behaviors for prerendered animations. This approach, however, is not possible when we wish to use autonomous, interactive characters that possess their own unique personalities and moods. Truly interactive characters must generate their behavior autonomously through techniques based upon what I call artificial emotion (AE).

Why do we have real emotion?

As human beings, we have an innate understanding of what emotions are. However, outside of academia, we rarely hear discussions on how emotions are produced and, more importantly, on why we have emotions. Within academia, these issues are subject to much contention and debate. That said, allow me to offer my own thoughts on these issues.

When attempting to simulate natural systems, we first need to ask, "What is the nature of this system and what is its purpose or reason for being?" Very few, if any, systems in the natural world exist for no reason.

Fujitsu’s fin fin

Emotions are an integral part of our decision-making systems. Emotions tune our decisions according to our personalities, moods, and momentary emotions to give us unique responses to situations presented by our environment. But why do we need unique responses to situations? Why don’t we all have the same responses? To answer this question, we need to look beyond the individual at humanity as a group or society of individuals. I believe personality has evolved as a problem-solving mechanism. Our unique personalities determine that we all think and hence solve problems in unique and different ways. In an evolutionary sense, this diverse method of solving problems is highly effective. If we had only one method of problem solving there would be a large, if not infinite, number of solutions that would be outside of our problem solving capabilities. So personality has evolved as a way of attacking problems from many different angles: from bold high-risk solutions to cautious and precise incremental solutions; from solutions discovered though deep thought and reflection to solutions discovered by gaining knowledge from others (socializing).

Emotion is, to a large degree, an emergent system. Its use must be looked at in terms of its interaction with society rather than in isolation to gain a better understanding of its reason for being.

We can look at a corporation as an example. Here, at the top of the hierarchy, we have a CEO who is bold and fearless, making broad decisions with little regard to details. At the other end of the hierarchy, we might find someone who is fearful of the unknown, is timid, and has great respect for details. The organization, and in a greater sense society, needs both types of people and the many others in between to function efficiently. Imagine if we all had identical decision-making systems, which gave us all the same responses to situations, but those responses were wrong. We wouldn’t last very long as a species.