6533b7d5fe1ef96bd12652ec

RESEARCH PRODUCT

Temperature sensation: the "3-bowls experiment" revisited.

subject

description

The "3-bowls experiment", usually attributed to E. H. Weber*, will be remembered by many from their first lab course in human physiology. The left and right hands are immersed for several minutes in bowls containing water at 10 and 40°C, respectively. When both hands are then placed in a third bowl of water at 27 °C, the left hand feels distinctly warm and the right hand distinctly cool. Until now nobody has been able to reconcile this apparent unreliability of the sense of temperature with the observation that humans regularly make judgements of the temperatures of objects; for example, mothers seldom use a thermometer to check the temperature of a baby's milk, but rather hold the bottle against the skin on their arm or face. Hensel [3] showed that human subjects are well able to make reproducible statements of steady temperature sensation in response to constant temperatures. Does this contradict the three-bowls experiment? The most direct way to resolve the issue is a reinvestigation of the experiment, testing the entire temperature range rather than using only a single combination. Human subjects adapted their left and right hands at 43 and 20°C, respectively, by immersion in water of the corresponding temperature for 15 min. However, the temperature in the test basin into which the subjects then plunged their hands could be varied between 13 and 46 °C in ten steps. The sensation of warm or cold on each hand was then judged on a scale between 4 (very cold) and + 4 (very hot) after 2 s of immersion. Between tests, the hands were readapted for 2 rain. The experiment was repeated using a simple