Water temperature and weight discrimination

Abstract

Previous experiments have shown that, in warm water, subjects adapt to the reduction of weight in water: after 10 min immersion their weight discrimination improves, and on leaving the water they suffer an after-effect when discrimination is impaired in air. The present experiment investigated changes in discrimination when immersing the arm in warm (27^°C) or cold (11^°C) water. Twenty-four subjects were tested at each temperature. All subjects showed a deterioration of similar magnitude between air and the first water lest. The cold group showed a further deterioration between the first and second water test, in contrast to the slight improvement of the warm group. They also show a deterioration between the first and second air tests, while the warm group showed none. It is argued that the relative deterioration of the cold group was probably due to numbing of the tactile senses, or perhaps to the distracting effects of cold pain.