Cognitive and embodied modes of spatial imagery

Cognitive repositioning refers to situations where subjects close their eyes in a familiar spatial surrounding and imagine switching positions and perspectives therein. Embodied repositioning refers to situations where subjects close their eyes and imagine the surrounding while actually walking or otherwise moving through them. Earlier experiments have shown that spatial imagery is more efficient under conditions of embodied than under conditions of cognitive repositioning and that the latter are the more difficult, the larger the amount of the to-be-imagined repositioning (e.g., as defined by turning angle) is. Such performance differences have been interpreted as evidence in favor of (1) facilitation effects going back to sensorimotor (i.e., motor and proprioceptive) information involved in self-movements in space, and (2) interference effects going back to incompatibilities between cognitive and sensorimotor representations of the spatial surrounding. An experiment is reported in which different effect hypotheses (facilitation, interference, a combination of both) are contrasted. In order to decide between these alternative hypotheses, a new mode of repositioning was introduced, in which subjects were systematically disoriented with respect to their actual body position in space. Subjects had to point to unseen object locations in their surrounding under different conditions of repositioning (modes: cognitive, embodied, disoriented; angles: 0 degrees, 60 degrees, 120 degrees, 180 degrees). Results revealed significant performance differences (pointing times and errors) between all three modes of repositioning. The introduction of the disoriented condition indicated that these differences are best accounted for by assuming interference as well as facilitation effects exerted by sensorimotor information in situations of imaginal repositioning.