ergonomics, the engineering science concerned with the physical and psychological relationship between machines and the people who use them. The ergonomicist takes an empirical approach to the study of human-machine interactions. The objective is to improve the efficiency of operation by taking into account a typical person's size, strength, speed, visual acuity, and physiological stresses, such as fatigue, speed of decision making, and demands on memory and perception. Applications range from the design of work areas (including office furniture, automobile interiors, and aircraft cockpits) to the disposition of switches and gauges on the control panels of machinery to determining the size, shape, and layout of keys on computer terminals and character height, color, and clarity on video displays. The field of ergonomics is also sometimes called human or human-factors engineering, engineering psychology, and biotechnology.