Effect on Complex Manual Performance of Cooling the Body While Maintaining the Hands at Normal Temperatures

¹ From the Psychology Branch, Environmental Protection Research Division, Quartermaster Research and Engineering Command, US Army, Quartermaster Research and Engineering Center, Natick, Massachusetts

Subjects were tested on complex manual performance tasks under two different conditions. In one the body and hands were cooled simultaneously, and in the other the body was cooled to the same degree while the hands were kept warm. A significant decrement in manual proficiency was observed when hand skin temperature dropped to 50–55°F, but no decrement occurred when hand skin temperatures were maintained at 80°F or higher, despite body surface cooling to 78°F in both cases. It was concluded that hand temperature is a vital factor in fine manipulation, but the body can be cooled to a degree which is distinctly uncomfortable without affecting manual performance if the surface temperature of the hands is maintained at normal levels.