Abstract
During each saccade the image of the world shifts across our retina yet we have little trouble keeping tracking of object locations in our surroundings. Transsaccadic perception of moving objects remains unclear. Previous transsaccadic perception studies investigating how well observers detect an object’s intrasaccadic displacement have used either stationary stimuli or moving stimuli over relatively small, orthogonal saccades relative to motion direction (Gysen et al. 2002). Here, we extend this literature by examining transsaccadic motion perception using smoothly translating motion targets (dot) over different saccade directions, amplitudes, and background conditions. Subjects were required to make a saccade when a fixation point moved from center screen to a different location. On some trials, the dot jumped forward or backward during the saccade. Subjects made a 2AFC response to indicate if they detected a displacement or not. Eye movements were measured using the SMI RED eye tracker. The first experiment we systematically varied saccade amplitude and direction to determine how different saccade metrics might influence subject accuracy in detecting intrasaccadic displacement of moving stimuli. We also examined the extent to which displacement size and relative post-saccadic location of the motion stimulus might influence detection performance. In the second experiment we varied the number and stability of allocentric cues presented in the background during the same transsaccadic tracking task as experiment one. In experiment one we found subjects were most accurate in detecting intrasaccadic displacement of moving targets when: 1) Saccades were small, retinal eccentricity of target was small, and target displacement was large. The second experiment confirmed these findings and we also found that allocentric background cues aided participant’s performance when they were stable or moving in the same direction as the target. Our novel findings suggest the same basic processes are involved in transsaccadic perception for both static and dynamic stimuli.