Sensation of resistor-induced warmth in blind persons.

It is commonly believed that the human sense of warmth is inferior in spatiotemporal acuity to the tactile senses. However, little or no evidence is available about the active feeling of warmth. We investigated the ability of people to detect in an active way small changes of warmth on very small areas (2-mm x 2-mm resistors). To that end, a new procedure was developed to measure perception of warmth. The results indicate that people who are able to detect the warmth stimuli perceive small incremental changes and that detection performance improves as stimulus intensity increases. Male subjects seem to be less sensitive than female subjects at lower level of stimulation, but this relationship is reversed at higher levels of stimulation.