Distraction effect of cold water on performance of higher-order tasks.

Eight U.S. Navy-qualified scuba divers performed peripheral target detection and navigation problem-solving tasks continuously during 3-h exposures to moderate (15.5 degrees C) and cold (4.5 degrees C) water. Upon exiting the water, the divers did a series of arithmetic computations. Measures of physiological cold stress were periodically recorded, and estimates of changes in body heat content were calculated. Results suggest a significant distraction effect of cold water exposure on performance of high-order tasks. Hour-to-hour comparisons of task performance between the two exposures showed no significant differences except for the in-water tasks during the first hour of exposure. Furthermore, individual performance levels achieved during second and third hours of cold water exposure were significantly correlated with levels achieved in moderate water and not with individual differences in body cooling. It is recommended that the psychologically mediated effects of cold exposure be given greater attention in both research and operations.