**5.1.2 Apparatus**

The haptic surface was a varnished wooden board mounted on a mechanical adjustable slant device (see Li & Durgin, 2009). The center of the surface was about 113 cm from the floor. A metal ridge was attached to the surface perpendicular to the axis of rotation as a guide. Participants stood in front of the apparatus wearing a blindfold (a plush sleep mask) throughout the experiment. The set-up is shown in Figure 8.

Fig. 8. The experimental set up. The orientation of the board could be rapidly adjusted to one of 16 orientations from 0° to 90°.
