Physiological Parameters of Mental Load

Abstract

The term mental load can be used for the implications of tasks calling on the information handling capacity of man. The essential aspects of the terms ‘ load ’ and ‘ capacity ’, as used in work physiology, are valid for mental load in the following ways: the question of the physiological ‘ costs ’ (biological consequences) of a given performance; external load to be measured in units of performance/time (signals/time, choices/time); capacity, dependent on time of endurance; physiological changes correlating with load; pathological symptoms due to extreme load. An experiment is discussed, where a simple binary choice task is used with several frequencies of signals to be answered; thus providing different loads. Systematic changes were found in heart frequency, sinus arrhythmia, systolic and diastolic blood pressure, rate of respiration, and so on. Arguments are put forward that these changes are due to a simultaneous rise in sympathetic and in vagal tone.