Q.20. How Fatigue is related to industrial accidents? Describe one industrial study on fatigue. (AKTU. 2012 - 13)
Ans. Crowden (1932) classifies muscular work in industry into three general types. The first is heavy muscular work that is too strenuous for a steady, continuous rate of work to be maintained. Examples of this type of work are loading trucks, building roads, and possibly mining coal. The second type consists of moderately heavy work that is continuous and in which the rate of expenditure of effort is much lower than in the first type and is somewhat balanced by the rate of recovery. Example of this type of work include machine tending and many other kinds of factory work. The relatively small expenditure of energy but which often requires a postural strain that causes unnecessary fatigue. Office work is a typical example.
Crowden found that in a fifty-yard barrow run the worker expends approximately 8 percent of his energy in raising and lowering the handles, 22 percent in attaining a wheeling speed and in stopping, and the remaining 70 percent in the rum itself. This study shows the tremendous inefficiencies that would result from interfering with the run once it is started.
Crowden reports that light speed work involves little expenditure of energy, but that there may be considerable fatigue because of the cramped or uncomfortable position maintained by the worker. Measurement of the actual expenditure of energy does not give a measure of fatigue with Crowden’s method because his measures basically the oxygen consumption in excess of normal.
The tremendous difficulty of the problem of fatigue is vividly illustrated by the research done by the United States Public Health Service on the relationship between fatigue and hours of work of interstate truck drivers. This is one of the mqst valuable studies in this field. The purposes of this study were (1) to determine if various periods of truck driving would produce demonstrable and significant psychophysiological changes; (2) to investigate the nature of these changes; and (3) to discover whether a characteristic pattern of psychophysiological response occurs after long hours of driving, i.e., the syndrome “drivers’ fatigue.”
Q.21. What is the impact of work environment on efficiency of the worker? What are ways and means to improve work environment? Explain “Arousal” Hypothesis as a model to understand the effect of auditory simulation upon the worker. (AKTU. 2012 - 13)
Ans. The problem of increasing production and also making work more pleasant has been approached through the introduction of changes in the working environment. There is a fundamental difference between this approach and that in which increased efficiency is attained as a result of time and motion studies. Although such studies sometimes lead to environmental changes, the changes are usually related to the job, such as changing the height of a stool or the size of a work area. In other words, time and motion studies most often result not in environmental changes but in changes in an integral part of the job or task being performed.
There are still other approaches, such as increasing efficiency through refined selection techniques. Under these circumstances no direct attention is given to the environmental factors related to the job.
The list of the Various environmental changes that could conceivably be introduced in industry is lengthy. Changes related to noise as it affects work, as well as changes in connection with the illumination, ventilation, and temperature of the work environment, have been introduced with varying claims of success. A popular environmental change is the introduction of music into the office or factory. Many claims in connection with a change in production have been based on the use of various color schemes, primarily on factory walls, but also on benches and machines, and in rest rooms.
Another category of environmental changes for improving production includes such miscellaneous items as eating facilities, fresh drinking water, and even the physical distance between two coworker.
Very little has been accomplished toward developing any type of theory relating human performance to either noise or music. The one notable exception is the application of the “arousal hypothesis” as a model for understanding the effects of auditory sti1iulation upon the worker. Duffy (1951) was one of the earliest to point out the possible importance of the overall level of activation of a person in determining his task performance. Activation level may be defined as “the degree of excitation of the brain stem reticular formation” (Scott, 1966). The determinants of an individual’s activation level are postulated to be such things as (1) stimulus intensity, (2) stimulus variation, (3) stimulus complexity, (4) stimulus uncertainty, and (5) stimulus meaningfulness.
Thus, intense stimulation, complex stimulation, etc. are postulated to be able to “arouse” the individual. Since noise and music are external stimuli which can be controlled in terms of intensity, variation, and meaningfulness, they qualify as potential “arousers.” Human performance, according to Duffy (1962), tends to vary in accordance with the general activation level of the individual. However, the relationship is not a direct linear one—rather, it is described better by an inverted U-shaped function, as s’own in Figure.
As Scott explains: “At low activation levels, performance is handicapped by lack of alertness, a decrease in sensory activity, and lack of muscular coordination (all of which are due to insufficient cortical stimulation from the BSRF). At intermediate levels of activation, performance is optimal, and at high levels performance is again handicapped by hypertensiveness, loss of muscular control, ‘impulse to action,’ and in the extreme, total disorganization of responses.”
Direct tests of the arousal hypothesis have not been frequent. Scott has reviewed the research and found it supportive of the hypothesis but still quite meager. Two recent examples of studies which have tried to tie music and noise effects on job performance to the arousal hypothesis are those of McBain (1961) and Smith and Cumow (1966).
