Visualizing the relations between slices and wholes is facilitated by co-location

摘要

Cross-sectional 2D images are widely used in medicine to represent 3D anatomy, but even experienced physicians have difficulty visualizing the relationship between the slices and the whole. Three experiments examined whether mental visualization is facilitated by displaying the cross sections in the physical space of the whole object. Subjects used a hand-held tool to scan and expose a hidden 3D object as a sequence of axial cross sections. A non-axial test angle was then indicated within the scanned space, and the subjects were instructed to visualize the corresponding cross section. A 2D test image then appeared, and the subjects indicated whether or not it matched the visualized cross section. The target's cross sections and the test image were either displayed directly at the source locations, by means of an augmented-reality display (in situ viewing), or displaced to a remote screen (ex situ viewing). In Experiment 1, both the target cross sections and the test image were presented in the same display mode, in situ or ex situ. Consistent with the hypothesis, we found that subjects achieved higher accuracy with the in situ than the ex situ display. In particular, displacing the images from the source induced failures to detect geometrical differences between the visualized cross section and test image. In Experiment 2, the test image was always displayed in situ. The disadvantage for ex situ exploration remained, showing that it is the visualization process, not the test, that is undermined by displacing the cross sectional displays from the source location. A third experiment confirmed this result by showing that ex situ viewing at test alone had no negative effect. These findings extend the advantages we have shown for in situ visualization in facilitating perceptually guided action, to the mental construction of complex object representations.