A high degree of mechanization may increase psychosomatic disorders, reduce job satisfaction, and contribute to a higher rate of absenteeism. Factors such as inter-personal relations at work, work stability, shift work, speed, and safety are important. Workers engaged in repetitive tasks, and controlled by machines, derive less satisfaction from their work. Shift work to sustain factory output capacities creates a psychosocial working environment that may adversely influence the health of the worker. Night work, and the change of working hours from one shift to another, may subject the workers to certain stresses. Such stresses affect the nervous system, increasing the frequency of peptic ulcer and of nervous symptoms, such as fatigue, nervousness, irritation, and insomnia. These nervous symptoms are usually related to lack of sleep, which in turn may be related to housing conditions, and especially to disturbance of sleep by noise during the day, if the worker is on the night shift.
An environment of machines creates ambient electromagnetism. Light quality or frequencies, sound vibrations and electrical and magnetic forces may disrupt the physical organism in subtle ways, for example acting through the nervous system, to affect attention, reaction times, or technical inspection or evaluation processes. Also where the ratio of work-space to worker is very high, or where workers are isolated for safety reasons or where strict regulations prevent human interactions on the job, stress may be induced. All these and other varieties of monotonous or dehumanized work are counter-productive.