Figure 1

(a) Illustration of a typical trial. A rightward (‘R’) or leftward (‘L’) cue informs participants which grasp to prepare before spatial frequency gratings are presented. Participants execute the cued grasp if they perceive the gratings to be identical in orientation. (b) Examples of leftward oriented spatial frequency gratings either side of a fixation dot that are the same in orientation (upper panel), different by a small degree of orientation (middle panel) and different by a large degree of orientation (lower panel). (c) Illustration of the response device used. Two graspable cubes with response buttons mounted to the top left/right corners and angled at 45° and 315° to afford leftward/rightward oriented grasps. The lever device below initiated each trial when pressed and collected reaction times when released. Figure adapted from²⁹.