TACTILE PATTERN-RECOGNITION BY GRAPHIC DISPLAY - IMPORTANCE OF 3-D INFORMATION FOR HAPTIC PERCEPTION OF FAMILIAR OBJECTS

Haptic recognition of familiar objects by the early blind, the late bl ind, and the sighted was investigated with two-dimensional (2-D) and t hree-dimensional (3-D) stimuli produced by small tactor-pins. The 2-D stimulus was an outline of an object that was depicted by raising tact or-pins to 1.5 mm. The 3-D stimulus was a relief that was produced by raising the tactors up to 10 mm, corresponding to the height of the ob ject. Mean recognition times for correct answers to the 3-D stimuli we re faster than those for the 2-D stimuli, in all three subject groups. No statistically significant differences in percentage of correct res ponses between the 2-D and the 3-D stimuli were found for the late-bli nd and sighted groups, but the early-blind group demonstrated a signif icant difference. In addition, the haptic legibility for the quality o f depiction of the object, without regard to whether or not the stimul us was understood, was measured. The haptic legibility of the 3-D stim uli was significantly higher than that of the 2-D stimuli for all the groups. These results suggest that 3-D presentation seems to promise a way to overcome the limitations of 2-D graphic display.