FLIPPING AND SPINNING - SPATIAL TRANSFORMATION PROCEDURES IN THE IDENTIFICATION OF ROTATED NATURAL OBJECTS

The proposal that identification of inverted objects is accomplished b y either a relatively slow rotation in the picture plane or a faster r otation in the depth plane about the horizontal axis was tested. In Ex periment 1, subjects decided whether objects at 0 degrees or 180 degre es corresponded to previously learned normal views of the upright obje cts, or were mirror images. Instructions to mentally flip an inverted object in the depth plane to the upright produced faster decision time s than did instructions to mentally spin the object in the picture pla ne. In Experiment 2, the effects of orientation were compared across a n object-naming task and a normal-mirror task for six orientations fro m 0 degrees to 300 degrees. In the normal-mirror task, objects at 180 degrees were cued for rotation in the picture plane or in the depth pl ane in equal numbers. The naming function for one group of subjects di d not differ from the normal-mirror function where inverted objects ha d been mentally rotated to the upright. For both functions, response t ime (RT) increased linearly from 0 degrees to 180 degrees and the slop es did not differ. The naming function for a second group of subjects did not differ from the normal-mirror function where inverted objects had been mentally flipped to the upright. For both functions, RT incre ased linearly at a similar rate from 0 degrees to 120 degrees, but dec reased from 120 degrees to 180 degrees. The results are discussed in t erms of theories of orientation-specific identification.