ABSTRACT
Spatial orientation involves several sensory cues that inform the brain about the position and motion of the body in space. Of particular importance are the vestibular and visual cues. In the dark, the perception of the body’s orientation with respect to the earth vertical depends essentially on the vestibular cue. How is the vestibular cue complemented or modified by the additional visual cues available in an illuminated environment? In order to resolve this question, researchers have presented human subjects (Ss) with conflicting visual and vestibular cues. A simple approach is the “tilting room” experiment, where the S is enclosed in a lighted chamber that is tilted to different degrees with respect to the earth stationary S. Confronted with such a conflict, Ss’ estimates of the vertical or their attempts to adjust their bodies to it show great variations. Some Ss base their responses mainly on the visual cue, others on the vestibular cue, and a third group apparently makes some kind of a compromise between the two cues (Witkin, 1949). Given appropriate instructions, Ss may align their bodies rather well to the earth vertical, even in the presence of a tilted visual field (Mann et al., 1949). In similar experiments by Kleint (1936, 1940), there were instances of bistability with the visual field appearing to flip back and forth between vertical and oblique, as well as instances of visual dominance, or a loss of orientation to the vertical altogether.
