Imagined Spatial Transformation of One's Body

This study examined two related phenomena: (a) the judgment of whether a human body part belongs to the left or right half of the body and (b) the imagined spatial transformation of one's body. In three experiments, observers made left-right judgments of a part of a body whose orientation differed from their own by a rotation about one of 13 axes. To do so, they imagined themselves passing to the orientation of the stimulus. Time for (a) left-right judgments and (b) accompanying imagined spatial transformations depended on the extent of the orientation difference (OD) between the observer and stimulus. More important, time for phenomena (a) and (b) depended strongly, and in the same way, on the direction of OD. Further results showed that the rate of imagined spatial transformations can vary strongly for different axes and directions of rotation about an axis. These and other results (e.g., Parsons, 1987a) suggest that temporal and kinematic properties of imagined spatial transformations are more object-specific than could be previously assumed.