Temporal recruitment along the trajectory of moving objects and the perception of position

The trajectory of a moving object provides information about its velocity, direction and position. This information can be used to enhance the visual system's ability to detect changes in these parameters. We show that the visibility of the trajectory of a moving object influences the perception of its position. This form of temporal recruitment builds up on a long timescale of approximately 500 ms. Temporary occlusion of the trajectory during this time period reduces recruitment, but does not abolish it. Moreover, we found no spatial restrictions on recruitment on the scale of 10 degrees of are. When the position of objects on trajectories with different degrees of visibility are compared, this recruitment effect causes spatial offsets. This leads to a visual illusion in which the position of moving objects is misperceived. (C) 1999 Elsevier Science Ltd. All rights reserved.