Material Discrimination and Thermal Perception

This research is focused on the development of a thermal display and understanding the nature of the thermal cues used to identify objects haptically. The objective of the present set of experiments was to measure material discrimination when thermal cues are the main source of information about the materials. A two-alternative forcedchoice task was used to assess discrimination. Of the five materials presented to the hand, nylon was the only material reliably discriminated as being warmer than the other materials. A second experiment was conducted to determine the magnitude of the skin temperature changes when contact was made with the materials. The results indicated that thermal responses were small, averaging 0.5oC. These findings suggest that temperature cues can be used to discriminate between materials, but only when the thermal differences are large. It appears that subjects respond more to variations in heat capacity than thermal conductivity when discriminating between materials.