Although emotion theorists disagree about many things, most agree on the premise that emotions are functional (Ekman, 1992; Lazarus, 1991; Shweder, 2000; Tomkins, 1984; Tooby & Cosmides, 1990), From one perspective, emotions serve intrapersonal functions including the regulation of memory, perception, attention, and a number of physiological processes (Ekman, 1992; Levenson, 1999; Tooby & Cosmides, 1990). In the past decade, however, the social functions of emotion within relationships have received increasing attention (Averill, 1980; Barrett & Campos, 1987; Keltner & Haidt, 1999; Keltner & Kring, 1998; Lutz & White, 1986). Humans are social creatures by nature, for whom group living is a key survival strategy (de Waal, 1996). Humans depend on social connections for survival across the life course, performing tasks such as generating, collecting, and sharing resources, detecting and responding to threats, and raising offspring in groups (Ainsworth, 1989; Caporael & Brewer, 1995; de Waal, 1996). Extended dyadic and group
interaction presents specific opportunities and problems that must be resolved for social units to succeed (Krebs & Davies, 1993; Trivers, 1971). Emotions play a critical role in the negotiation of this social terrain.