Scientific management. According to Henry Ford, the assembly line was based on three simple principles: "the planned, orderly, and continuous progression of the commodity through the shop; the delivery of work instead of leaving it to the workman's initiative to find it; an analysis of operations into their constituent parts." A scientific approach to these principles, the next logical step in the organization of work, had already been enunciated by the American industrial engineer Frederick W. Taylor (1856-1915). From his work an entirely new discipline--industrial engineering or scientific management--emerged, in which the managerial functions of planning and coordination were elevated to a primary position in the productive process.

In Taylor's view, the task of factory management was to determine the best way for the worker to do the job, to provide the proper tools and training, and to provide incentives for good performance. Taylor broke each job down into its constituent motions, analyzed these to determine which were essential, and timed the workers with a stopwatch. With superfluous motion eliminated, the worker, following a machinelike routine, became much more productive. In some cases, Taylor recommended a further division of labour, delegating some tasks, such as sharpening tools, to specialists. (see also Index: time-and-motion study)

These studies were complemented by two of Taylor's contemporaries in the United States, Frank B. and Lillian M. Gilbreth, whom many management engineers credit with the invention of motion studies. In 1909 the Gilbreths, studying the task of bricklaying, concluded that much motion was wasted by the worker in reaching down to pick up each brick. They devised an easily adjusted scaffold that eliminated stooping and improved average work performance from 120 to 350 bricks per hour. Industrial engineering ultimately came to include all elements of factory operation within its compass--layout, materials handling, and product design, as well as labour operations.

Taylor regarded his movement as "scientific" because he attempted to apply scientific principles and measurement to the work process. Many previous advances in manufacturing had been made by applying scientific principles to machines in order to make them more efficient, and, through his minute subdivision of labour, Taylor sought to do the same to the work process itself. This scientific approach, however, neglected the human element, so that Taylor in effect converted the work process from a relationship between worker and machine into a relationship between two machines.

Scientific management theorists assumed that workers desired to be used efficiently, to perform their work with a minimum of effort, and to receive more money. They also took for granted that workers would submit without question to standardization of physical movements and thought processes. Their system, however, ignored human feelings and motivations, leaving the worker dissatisfied with the job. Furthermore, some employers omitted the altruistic elements in Taylor's system and employed time and motion studies to set high norms of production and speed up the production line while still keeping wages down.

Industrial psychology. In the decade after 1910, when the principles of scientific management were being applied wholesale in U.S. industry, union opposition arose. Though the unions approved more efficient production arising from better machinery and management, they condemned the speedup practice and complained in particular that Taylorism deprived workers of a voice in the conditions and functions of their work. Complaints were also made that the system caused irritability and fatigue along with physiological and neurological damage among workers. Misuse of the human element in production was causing declines in both quality and productivity. Industrial engineers then faced the problem of motivating the worker so that the combination of human labour and machine technology would achieve its fullest potential. A partial solution came from the social sciences, and, in the process, industrial psychology emerged. (see also Index: trade union)

The major premise of this new discipline was that mass production technologies affect the worker both in the immediate job environment and in relations with fellow workers and supervisors. The first important discoveries in the social context of mass production technology resulted from experiments made by the American social scientist Elton Mayo between 1927 and 1932 at the Hawthorne plant of the Western Electric Company, in Cicero, Ill. Mayo, who earlier had studied problems of physical fatigue among textile workers in a Philadelphia plant, was called in to the Hawthorne works, where industrial engineers were considering the potential effect on productivity of changes in illumination. The investigators chose two groups of employees working under similar conditions to produce the same part; the research plan was to vary the intensity of the light for the test group but to keep it constant for the control group. To Mayo's surprise, the output of both groups rose. Even when the researchers told one group that the light was going to be changed and then did not change it, the workers expressed satisfaction, saying that they liked the "increased" illumination, and productivity continued to rise.

Mayo saw that the significant variable was not physiological but psychological. A second series of experiments was performed, involving the assembly of telephone relays; test and control groups were subjected to changes in wages, rest periods, workweeks, temperature, humidity, and other factors. Output continued to increase no matter how physical conditions were varied; indeed, even when conditions were returned to what they had been before, productivity remained 25 percent above its original value. Mayo concluded that the reason for this lay in the attitudes of the workers toward their jobs and toward the company. Merely by asking their cooperation in the test, the investigators had stimulated a new attitude among the employees, who now felt themselves part of an important group whose help and advice were being sought by the company. The name Hawthorne effect was given to such beneficial changes in workers' attitudes, and, within a short time, scientific management incorporated these new findings. (see also Index: Hawthorne research)

Mayo's studies had suggested that consultation, usually in the form of interviews between labour and management, gave workers a sense of belonging to a team. Industrial engineers and sociologists have suggested additional approaches toward improving motivation and productivity. These include job alternation to relieve boredom; job enlargement, or having the worker perform several tasks on a project rather than performing a single operation; and job enrichment, redesigning the job to make it more challenging.

In a sense, Mayo's work made scientific management even more scientific, because he brought the new behavioral sciences, like social psychology, into the problems of organizing work and the labour-management relationship. It encouraged the development of human-factors engineering and ergonomics, disciplines that attempt to design "user-friendly" equipment accommodating itself to the human physiology and nervous system. For example, the new engineers try to make certain that a worker's equipment is operable with minimum strain, at a comfortable work level, and with controls easy to reach, see, and manipulate. In brief, they attempt to design the machine around the human mind and body.