Abstract
When objects undergo smooth or implied motion and unexpectedly vanish, observers report their vanishing point as farther along the motion trajectory than the actual vanishing point. This forward displacement is known as representational momentum (RM; Freyd & Finke, 1984). Two studies investigated whether and how stimulus type influences RM. If RM is due to a memory error, then the magnitude of RM should be unaffected by stimulus type. If RM reflects motor simulation or prediction, then stimuli that afford perception-action coupling should produce different RM patterns. In Experiment 1, 60 observers performed the standard representational momentum task with an arm, wrench, and rectangle. Trials were blocked by stimulus type in a within subjects design. On each trial, the stimulus underwent implied rotation around a central axis. 60 participants judged whether a subsequently presented probe was identical to the final stimulus view. Results show that, collapsed across stimulus type, RM increased across blocks. Further, the arm provided for the smallest RM, the rectangle most, and the wrench in between. This suggests that human movements may be differently treated by the visual system. Experiment 2 replicated the previous study but used an arm and a tree (a non-manipulable object) and stimulus type varied across subjects. Results show an interaction between stimulus type and block. Forward displacements for the arm decreased from Block 1 to Block 2, while forward displacements for the tree increased from Block 1 to Block 2. The results of these studies indicate that representational momentum varies across stimulus type. Future studies will examine alternative explanations such as the complexity of the image, attentional factors, meaningful vs. meaningless movement, and animacy vs. inanimacy.
New Jersey Governor's Council on Autism.