### Hardware * Apple eMac computers * CRT monitors * 17 inches * 1024 x 768 resolution * 89 Hz refresh rate * 56 - 60 cm view distance * Viewing aperture affixed to the monitor, constructed from safety goggles and a fabric tube ### Software * MATLAB 2007b * Psychophysics Toolbox version 3 ### Stimuli and Procedure The stimuli used were arrays of 6 Gabors presented on a gray background. These Gabors had a diameter of 56 pixels/1.6˚, with a spatial frequency of ~ 1.5 cycles per degree and a randomly chosen orientation. They were placed in fixed positions (at 30˚, 90˚, 150˚, 210˚, 270˚, and 330˚ relative to the horizontal) in a ring around a central fixation cross (0.3˚ by 0.3˚/10 by 10 pixel) at a radius of 75 pixels/2.30˚, measured from the center of the cross to the center of the Gabor. Each trial began with the fixation cross presented alone in the upper-left of the display for 500ms, followed by the onset of the Gabor array. The array immediately started moving downward along the left edge of the display for a distance of 13.09˚ of visual angle (426 pixels) at a constant velocity of 19.14˚ per second (7 pixels per refresh). When the Gabor array approached the lower left corner of the screen, it immediately turned 90˚ to the right and continued at the same speed for 18.99˚/618 pixels. When it reached the end of its path, the array offset and reappeared in the center of the display under the words “Click the one that rotated.” On every trial, one Gabor rotated 15˚ clockwise in a single refresh. There were two possible conditions: * In the “flexion” condition, this rotation occurred the moment the array changed direction in the lower-left corner. * In the “control” condition, this rotation occurred after the direction change, halfway along the horizontal portion of the array's motion. The target orientation change occurred equally often (5 times) at each of the 6 Gabor positions across both the flexion and control condition, for a total of 60 trials. These 60 trials were randomly ordered for each participant. ![Schematic of experiment 1][1] Curved arrow indicates the point of target rotation in the flexion (blue) and control (orange) conditions. [1]: https://mfr.osf.io/export?url=https://osf.io/pk38s/?action=download%26mode=render%26direct%26public_file=False&initialWidth=684&childId=mfrIframe&format=1200x1200.jpeg