Date Published: June 4, 2019
Publisher: Public Library of Science
Author(s): Robin Welsch, Christoph von Castell, Heiko Hecht, Rick K. Wilson.
Violations of personal space are associated with discomfort. However, the exact function linking the magnitude of discomfort to interpersonal distance has not yet been specified. In this study, we explore whether interpersonal distance and discomfort are isotropic with respect to uncomfortably far or close distances. We also extend previous findings with regard to intrusions into personal space as well as maintenance of distances outside of personal space. We presented subjects with 15 interpersonal distances ranging from 40 to 250 cm and obtained verbal and joystick-based ratings of discomfort. Whereas discomfort rose immediately when personal space was entered, the gradient was less steep for distances that exceeded the comfort region of personal space. Thus, personal space is anisotropic with regard to experienced discomfort.
As a stranger approaches us, there comes a point where we start to feel uncomfortable and intruded upon. Our feeling of an inappropriately large or short distance with respect to another person can be conceived of as a personal space (PS) requirement accompanied by a feeling of psychological distance. How PS extends and shapes distance-behavior has first been studied in animals. For example, animals in captivity claim a relatively smaller territory and flight zone, as compared to wild animals . Sommer  pioneered proxemic research in humans. He observed that when interacting with others in a hospital, schizophrenic patients claimed a larger portion of space to themselves as compared to non-schizophrenic patients. Hall  took up the idea of interaction distances and proposed four distinct spaces by their radius, mainly based on the appropriateness of potentially available sensory perceptions: intimate space (0–45 cm), personal space (45–120 cm), social space (120–365 cm), and public space (365–762 cm). These ranges have been replicated within a large set of different nationalities and cultures , in various measures of interpersonal distance (IPD, ) as well as in virtual environments [6–9].
Unlike previously thought, the response to violations of PS is rather immediate. That is, our data do not support the notion of a tolerance zone around the preferred IPD where intrusion or extrusion is acceptable in the sense that it leaves comfort ratings unaffected. Most importantly, preferred IPD in the stop-distance tasks corresponds to the shortest distance without discomfort in the rating-task. Spontaneous variations in IPD occur in the range of 10–15 cm and seem to be unrelated to the mean IPD (see Fig 2). Thus, the stop-distance task is rather reliable and seems to produce a valid approximation of the borders of PS. The tolerance for violations of PS previously observed in other studies , may merely be an artifact of aggregation across subjects, which may mislead into suspecting a larger acceptable range or even a U-shaped function of IPD and discomfort. Note, however, that we cannot rule out a tolerance for violations of PS smaller than 15 cm as we sampled distances in steps of this size. Within this range, spontaneous variations in preferred IPD may occur. Furthermore, we merely sampled distances from 40 cm to 250 cm and found a linear increase of discomfort with deviation from PS, this might not hold for extrusions of more than 200 cm.