Human thermoregulatory behavior during a conflict between cold discomfort and money.

A conflict was contrived between thermal and non-thermal drives in humans to study the effects of varying degrees of voluntary suppression of behavioral temperature regulation. Five, young, near-nude males were paid 2, 5, 10, 20 or 40 cents per min to expose themselves to increasing cold (15 degrees to 0 degree C in 2 hours), after being instructed to terminate the exposure as soon as the cold discomfort exceeded the monetary reward. The duration of voluntary cold exposure was approximately linearly related to the logarithm of monetary reward. Reported cold discomfort was greater with high than with low rates of reward. Although V02 approached summit metabolism, the capacity for shivering did not appear to limit cold tolerance. Subjects adopted various strategies for coping with the conflict but, in general, greatest cold tolerance was recorded in subjects of large body mass and willing to tolerate low Tsk.