Fig. 1.

Haptic experiment stimuli and design. (A, Upper) Images showing a rendered example stimulus from each of the four stimulus categories used in Exp. 1: faces (F), hands (H), mazes (M), and chairs (C). (Lower) Experimental design in which the participants haptically explored the stimuli presented in blocks. Sighted participants viewed these rendered stimuli rotating in depth; both sighted and blind subjects haptically explored 3D-printed versions of these stimuli. Both haptic and visual experiments included two blocks per stimulus category per run, with 30-s rest blocks at the beginning, middle, and end of each run. During the middle rest period in the haptic condition the turntable was replaced to present new stimuli for the second half of the run. (B) The stimuli were presented on a rotating turntable, to minimize hand/arm motion. The subjects explored each 3D printed stimulus for 6 s after which the turntable was rotated to present the next stimulus. (C) Image showing an example participant inside the scanner bore extending his hand out to explore the 3D-printed stimuli on the turntable.