Arf, perceived changes in position consistent with perceived self-motion?

Abstract

Purpose: II is possible to track (he egocentric position of an object during locomotion using cither perceived 3D layout and self-motion, or the 2D flow pattern. When perceived 3D path of self-motion is erroneous, are perceived object locations updated in a way consistent with the erroneous interpretation? Method: The task was to track a previously cued location on the ground during simulated self-motion for 2s, and then indicate its final position with a cursor. Three types of motion were simulated: movement on a circular path (Curved condition), movement along a straight path (Straight condition), and movement along a straight path while rotating (Rotating condition). Simulated translation and rotation is known to produce an illusion of travel on a curved path under these conditions. Therefore, if position judgments in the Rotating condition are based on the erroneous interpretation of self-motion, performance should be similar to the Curved condition, but if the 2D flow is used, performance would be the same as the straight condition. Results: For each condition, the mapping from initial positions to judged final positions was fit to a Euclidean transformation, which was used as a measure of the subjective change in observer position. The translational component of this transformation differed between the Curved and Straight conditions, but not between the Rotating and Straight conditions. Conclusion: Subjects appear to use the 2D flow pattern to track the egocentric positions of objects, even when these judgments are inconsistent with the perceived path of self-motion. This suggests (hat there is no single interpretation of 3D layout and self-motion.