Abstract
Previous studies in locomotion have focused on the perceptual information present in the scene. The purpose of the current study was to investigate the role of attention on performance on heading judgment tasks. Subjects viewed a 3D scene containing objects lying on a ground plane. The scenes were presented in two frames: the first frame showed the subjects' initial position, and the second frame showed the scene from a different viewpoint as if the subject walked from the first to the second position. Subjects were judged their heading direction relative to a pole in the distance. The first frame contained 12 objects, of which 4 were red, 4 were green, and 4 were blue. The second frame contained only one set of the colored objects; for example, 4 red objects remained while the green and blue objects disappeared. An ISI (blank screen of 50 or 1000ms) was presented between the frames to simulate the presence or absence of apparent motion. Subjects were validly cued, invalidly cued, or neutrally cued to a set of colored objects. In the valid-cue condition, subjects were cued to attend to the color of the objects that remained from the first frame to the second frame. In the invalid-cue condition, the participants were cued to attend to one color of objects that will not be present in the second frame. In the neutral-cue condition, the participants were cued to attend to all 12 objects. Our results show that accuracy in heading judgments increased as heading angle increased. Subjects had greater accuracy when apparent motion was present than when apparent motion was absent. Most importantly, subjects had greater accuracy at the valid condition as compared to the invalid and neutral conditions. The results suggest that attention operates during locomotion, and subjects can selectively attend to specific objects or groups of objects in the scene that are relevant for heading judgments. The role of attention in extracting landmark information will be discussed.
Supported by NIH AG13419-06