Abstract
Spatial context has been shown to affect the perceived location of an object. An object surrounded by a frame that is offset relative to one's midline is perceived to be more centrally located than it actually is (induced Roelof's effect). Remarkably, that same object will be accurately localized when subjects must point to it (Bridgeman et al., 1979). Differences in perception and action responses have been used to support the view that visual information is processed differently depending on whether the information is used for perception or action. Here we show a sex difference in the effects of context on spatial localization, predominantly revealed by an action response. Ten subjects wearing a head-mounted display, and viewing a virtual environment, were briefly presented (1 s) a scene of an object (2°-diameter ball) in a doorway (20.5° wide). Subjects were instructed to either verbally report the object's position relative to themselves or to walk to it. The object was positioned at −3°, 0°, or 3° relative to the subject's midline, and the doorway was either centered or offset by 5° to the left or right of the subject's midline. All subjects exhibited the typical Roelof's effect in their verbal report, with average object mislocalizations of 2.2° (men) and 4.2° (women) for the offset doorway conditions. However, when the subjects had to walk to the object, spatial context had little effect on the men's endpoints (average deviation <1°) but had significant effects on the endpoints of the women (average deviation >4°). These findings suggest a basic difference in men and women with respect to the effects of context on spatial processing as it relates to navigation and may help explain reported sex differences in navigation ability.
Bridgeman, B. et al. (1979). Relation between cognitive and motor-oriented systems of visual position perception. Journal of Experimental Psychology: Human Perception and Performance, 5, 692–700.