ABSTRACT
Fifty-three muscles are responsible for the wide range of expressions and face shapes available to humans. These muscles fire in patterns to produce the conceived result. Human expressions cross cultural, regional, and linguistic boundaries. Emotion and the ability to classify emotions is a debated subject. There is a categorical model which defines a number of discrete emotional states and there is a dimensional model which maps a range of emotional phenomena onto an explicitly dimensioned space. References for these approaches are listed at the end of this chapter. Looking at emotion categorically, we express happiness, sadness, anger, fear, surprise, and disgust, the so-called six basic emotions, in addition to all the more complex emotional reactions with the same sets of muscles. Facial muscles function similar to skeletal muscles in the rest of the body. Below is a list of muscles which may be a relevant starting point for a muscle-based facial setup (Figures 16.1 and 16.2).
