Equilibrium Theory Revisited: Mutual Gaze and Personal Space in Virtual Environments

During the last half of the twentieth century, psychologists and anthropologists have studied proxemics, or spacing behavior, among people in many contexts. As we enter the twenty-Žrst century, immersive virtual environment technology promises new experimental venues in which researchers can study proxemics. Immersive virtual environments provide realistic and compelling experimental settings without sacriŽcing experimental control. The experiment reported here tested Argyle and Dean’s (1965) equilibrium theory’s speciŽcation of an inverse relationship between mutual gaze, a nonverbal cue signaling intimacy, and interpersonal distance. Participants were immersed in a three-dimensional virtual room in which a virtual human representation (that is, an embodied agent) stood. Under the guise of a memory task, participants walked towards and around the agent. Distance between the participant and agent was tracked automatically via our immersive virtual environment system. All participants maintained more space around agents than they did around similarly sized and shaped but nonhuman-like objects. Female participants maintained more interpersonal distance between themselves and agents who engaged them in eye contact (that is, mutual gaze behavior) than between themselves and agents who did not engage them in eye contact, whereas male participants did not. Implications are discussed for the study of proxemics via immersive virtual environment technology, as well as the design of virtual environments and virtual humans. 1 Equilibrium Theory Revisited: Mutual Gaze and Personal Space in Virtual Environments Proxemics, the study of personal space and interpersonal distance, began more than four decades ago. Hall (1959) and Sommer (1959) demonstrated that people maintain personal or buffer space around themselves and each other. Although the size of the buffer space remains remarkably stable across individuals, certain conditions—for example nonverbal expressions of intimacy (such as mutual gaze)—foster its expansion or contraction. Argyle and Dean (1965) describe the interaction between mutual gaze and proxemic behaviors. According to their intimacy equilibrium model, the two behaviors are inversely related to each other. Mutual gaze nonverbally promotes intimacy which, if inappropriate to the relationship between interactants, is decreased by increases in personal space (which nonverbally promotes less intimacy). Immersive virtual environments (IVEs) raise at least two intriguing issues for proxemics research. One involves the validity of using IVE technology (IVET) Bailenson et al. 583 to study proxemics experimentally. If IVET is methodologically valid for this purpose, then it provides a powerful research tool. Investigators can study proxemics with complete control over virtual human representations while at the same time maintaining a relatively high degree of ecological validity and mundane realism (Aronson & Carlsmith, 1969). A second issue concerns IVEs as a new type of space that may itself affect nonverbal and proxemic behaviors within them. 1.1 Nonverbal Communication Patterson (1995) deŽnes nonverbal communication as the “transmission of information and inuence by an individual’s physical and behavioral cues” (p. 424). Nonverbal communication has been studied extensively in psychology (for a review, see Argyle (1988)), anthropology (Hall, 1966; Watson, 1970), and computer science (Badler, Chi, & Chopra, 1999; Isbister & Nass, 2000). Nonverbal signals can be expressed through many channels, ranging from subtle ones such as voice intonation, to more obvious ones involving hand gestures. Moreover, these behaviors are often subconscious and unintentional (Zajonc, 1980).