Multiple-object tracking is based on scene, not retinal coordinates

Abstract

This study tested whether multiple-object tracking—the ability to visually index objects on the basis of their spatiotemporal history—is scene based or image based. Initial experiments showed equivalent tracking accuracy for objects in 2-D and 3-D motion. Subsequent experiments manipulated the speeds of objects independent of the speed of the scene as a whole. Results showed that tracking accuracy was influenced by object speed but not by scene speed. This held true whether the scene underwent translation, zoom, rotation, or even combinations of all 3 motions. A final series of experiments interfered with observers ’ ability to see a coherent scene by moving objects at different speeds from one another and by distorting the perception of 3-D space. These reductions in scene coherence led to reduced tracking accuracy, confirming that tracking is accomplished using a scene-based, or allocentric, frame of reference. An important task of the visual system is to keep track of objects as they move through space. Whether the observer is an air traffic controller tracking airplanes on a radar screen or an athlete track-ing team members and opposing players on a field, there is a need to maintain a visual index for objects that are changing in thei