Figure 1. Stimuli.

A–B The positions of drifting Gabor patterns are perceived as shifted in the direction of internal motion, although their contrast envelope remains stationary [4]–[6]. Physical and perceived positions are dissociated. C The main stimulus used in the present study. A tilted Gabor target is presented at 14 degrees eccentricity to the left or right of the fixation point. Surrounding the target are six distractor Gabors arranged in a hexagonal ring, oriented such that they can be drifted either towards or away from the target. D In each trial of Experiment 1A, the stimulus was presented twice. In the second presentation interval distractors drifted in the opposite direction of the first interval, and the physical position was changed. Participants judged in which interval the distractors appeared as spaced wider. In the example shown, although the physical spacing in the first (inward drifting) presentation is much larger than in the second (outward drifting) presentation, the stimuli are perceived in identical positions.