Two Concepts of Emotional Expression

Abstract

“Emotional expression” is an unfortunately ambiguous term. Scientists define it in two distinct ways, and this difference in definition leads them to employ the term inconsistently. In some experimental contexts, “emotional expression” names all and only those behaviors that follow emotional arousal. In other experimental contexts, “emotional expression” names all and only those behaviors that convey information to observers about a creature’s affective state. Importantly, these two concepts are not co-extensive; each includes members not included in the other. Once I have disambiguated the two senses of the term, I demonstrate that equivocation has interfered with at least two ongoing empirical projects, namely the debate over the universality of emotional expression and the debate over the evolution of emotional expressions as communicative signals.