In my first major effort at elaborating Differential Emotions Theory (DET), I proposed that personality was a supersystem consisting of five separate though highly interacting subsystems (Izard, 1971). The emotions were conceived as one of the subsystems of personality, and, following Tomkins (1962), the emotions were viewed as the primary motivational system for human behavior. Furthermore, each discrete emotion was interpreted as a system with distinct though interacting components. Although DET has changed to accommodate new thought and data, the essence of the systems approach has remained integral (cf. Izard et al., 1995). The systems concept is important in presenting a perspective on facial expressions, because the perspective I present hinges on the concepts of systems and separate, dissociable components.

Facial expression (as well as vocal, postural, gestural expression) is conceived as an evolved, genetically influenced but highly modifiable and dissociable component of emotion. However, as stated on previous occasions (e.g., Izard, 1977), observable expression is not viewed as a necessary component of emotion. One goal of this chapter is to summarize the argument for this position and to place it in perspective by addressing two kinds of counterarguments, argument against the evolutionary-genetic origin of facial expressions and argument against their links to emotion (feeling/motivational) states. Another goal is to reaffirm the theoretical significance of the concept of patterns. In DET, the term pattern refers to one of two phenomena: A set of movements that index a discrete emotion or a set or cluster of discrete emotions that interact to produce complex affective phenomena such as anxiety and depression (Izard & Youngstrom, 1996).