Warm and cool thresholds as a function of rate of stimulus temperature change

The variables which are said to affect human temperature sensitivity are the skin temperature, the area of thermal stimulation and the rate at which the temperature of the skin is changed. Of these, the last has been only partially described. Measurements of the warm and cool thresholds were made on two males, experienced in making threshold judgments, when the rate of stimulus temperature change was varied between 0.01–0.3° C/sec. Both the warm and cool thresholds remained constant at rates of 0.1° C/sec and above but increased rapidly when slower rates were used. The effect of slow rates of stimulus temperature change was greater on the warm threshold than upon the cool threshold. It is concluded that the rate of temperature change does not represent information about the rate constants of stimulation of warm and cool receptors but that its effect is by way of the rate at which thermal adaptation occurs