When auto pioneer Henry Ford introduced the assembly line, he described it as a "haven for those who haven't got the brains to do anything else," a mind-numbing notion that has dominated the American workplace for most of the 20th Century.

Now the auto industry, which gave the world the robot-theory of mass production, is pioneering in the dismantling of the system it did so much to create - largely by inviting workers to put their brains as well as muscles to work.

Surprisingly enough a leader - perhaps the leader - other than the biggest assembly line operator of them all: the General Motors Corp., the nation's largest auto who manufacturer and its biggest indusrtial employer, with 560,000 employees at 112 plants in 35 divisions spread over 18 states.

In co-operation with the United Auto Worker, GM is encouraging scores of so-called "quality of worklife" projects aimed at making work more satisfying by giving workers a voice in determining what they do and how they do it.

The projects vary in size, scope and practical application, ranging from small offices to entire assembly plants, from flexible scheduling of work hours to redesign of jobs, production areas and whole patterns of decision making.

Many plants are still operating largely under old rules, the number of workers who can claim that their work is substantially different is still modest, and cooperate and union gurus of the movement are careful not to proclaim the arrival of a new industrial millennium.

But the very fact that GM is involved at all - considering its size, corporate complexity and historical identify with the development of mass production techniques - gives a powerful new impetus to a movement that has more often been associated with ivory towers than corporate board rooms and union halls.

"It's slow and evolutionary, but it's become the norm at GM," says Development L. Landen, GM's director of organizations research and development.

"In terms of scale, I don't know of any other corporation that has as much going as GM," says Irving Bluestone, international vice president of the United Auto Workers in charge of its GM division.

Sidney Harman, who championed the work improvement concept as chief executive of Harman International Industries before becoming Under Secretary of Commerce earlier this year, shares the view that something important is happening at GM.

"Over the past couple of years there's been a very significant change in the form of a new awareness by chief executive officers of large corporations who in the past regarded quality-of-worklife programs with skepticism if not wry amusement," said Harman in a recent interview. "Now many of them are taking a lead. There is no better example than Tom Murphy" - GM's Board Chairman and Chief Executive Officer.

Another key element - some say the key element - has been the dogged determination of Bluestone, whom Landen describes as a "visionary" in the field.

Bucking the suspicions of many union leaders, including some within the UAW, that such ventures will necessarily undermine unions, the scholarly, soft-spoken Bluestone believes that work improvement programs can benefit everyone if they are built upon strong collective bargaining relations, operate indepently of them and involve the union as well as management at all levels. Bluestone believes unionization is a necessary prerequisite, although some others disagree.

To Bluestone, the new way is a negation of the authoritarianism and rigimentation of the old way, rather than a new set of rules, procedures or goals. A joint GM-UAW committee exists to encourage experimentation but "the cardinal principle is that ideas must come from the bottom up," he says. Precise mechanisms are less important than a continual effort to involve workers more deeply in all decisions affecting their jobs. "There's no rule, there's no limit," says Bluestone. "It's a constant process of cut and try, cut and try . . . limited only by the ingenuity of man.

"In every case where I've participated," said Bluestone recently, "the union has benefited, the worker has benefited, and there is greater strength."

One of the most far-reaching GM projects resulted in reorganization of 2,300 supervisors, technicians and production workers at the Fisher Body Plant No. 2 in Grand Rapids, Mich., into semi-autonomous business teams, with members jointly setting goals and sharing responsiblity for them. Decisions normally made unilaterally by management, such as whether to do work in a plant or contact it out, are now made jointly.

At a big assembly plant in Tarrytown, N.Y., a problem with breakage in the glass installation department led to special training in problems solving techniques for the department's 60 employees. It has now been extended to all 3,400 workers, with a noticeable decline in grievances and rise in productivity, according to GM's Landen.

In a 1976 corporate report, GM also told of a car division where 250 production workers overhauled blue-prints for relocating their work area, altering traffic flow and modifying hoist facilities - resulting in reduced overtime and what the effort called "improved working relationships among managers and employees."

Also, grievances in GM's 18 assembly plants, where labor-management relations tend to be most difficult, plummeted from an annual rate of 55,000 to 12,000 between 1973 and 1976 - largely the byproduct, Landen says, of the work improvement programs.

According to Geroge B. Morris Jr., vice president in charge of GM's industrial relations staff, there has been a gradual reversal of the long-entrenched corporate priorities.

Before, the emphasis was on organizational efficiency, Morris told the Society of Automotive Engineers last March. We saw improvements in the work climate as naturally flowing from these efforts. I think now we have reversed those objectives. Our primary objective now is to improve the quality of worklife. We feel that by concentrating on the quality of worklife and wisely managing the systems that lead to greater job satisfaction and feelings of self-worth that improvements in the effectiveness of the organization will follow."

Or, as Harman put it, only semi-facetiously, "they've decided that what's good for General Motors."

This is a far cry from the image of GM that emerged, fairly or unfairly from the highly publicized Lordstown. Ohio, strike in 1972. At least partly in protest against the automation-like roles that they were programmed to fill, auto workers, many of them young, greeted the opening of a "model," superefficient new GM assembly plant by shutting it down - the ultimate revenge of the robots.

The genius of the old system - so long as it functioned productively - was that it required so little genius to operate. Workers were extensions of the machines they manned, interchangeable parts programmed by production standards, time-motion studines, time clocks, shop rules, foremen, union stewards and more recently even computers. They were Henry take much brainpower to stand in the same place eight hours a day pulling the same lever 200 times an hour, 1,000 time aday.

Even off he assembly line, in white-collar as well as blue-collar jobs, the regimentation of work stood as a major exception to what textbooks taught about basic American precepts of free choice, individualism and creative enterprise. Where machines failed to dominate, bureaucracies prevailed.

Strains in the system began to emerge during the ferment of the '60s, reflected a rising absenteeism and job turnover rates, concern over lagging productivity and sloppy quality of work and talk of worker alienation - the "blue collar blues" and "white collar woes," a malady especially pronounced among better educated younger workers who drew larger lessons from Bob Dylan and the Beatles than they did from the Depression and breadlines.

Thus the quality-of-worklife movement took root, a sort greening of the workplace that captured the imagination of idealists and sent a tremor through the ranks of tranditionalists, union and managment alike. It followed lines already developing in Western Europe, particularly Scandinavia, although differences were and continue to be as pronounced as similarities.

More was involved than a blossoming of humanism, however, Pragmatists saw opportunities for reduced costs and higher productivity that stemmed from a happier and more creative work force.

Michael Macroby, a leading theorist of the work humanizing movement, points to other factors too: an increasingly sophisticated technology that requires more decision-making on the part of workers, and foreign competition, coupled with rising costs of energy and raw materials, that has intensified pressure for greater utilization of human resources. "Put it all together and it was a powerful mator," said Maccoby recently.

What Maccoby sees now is a "period of experimentation, with the bad projects shaking out." Many have flowered and then failed: others have endured.

Besides GM, other big corporations that have undertaken quality-of-work-life projects include the Weyerhaeuser timber products company, the Harman automosive division and the Nabisco food processing firm, with Nerox and the American Telephone and Telegraph Co. not far behind, according to Ted Mills of the Washington-based American Center for the Quality of Work Life.

In Jamestown, N.Y., work improvement became a civic project, a joint effort by government, employees and unions to save recession-threatened jobs that evolved gradually into an imaginative community campaign to enhance job satisfaction. Similar projects are now under way in communities ranging from San Bernardino, Calif., to Cumberland, Md. The state of Massachusetts has also set up an office to foster such programs.

Several city governments, including San Diego, Calif. and Columbus and Springfield, Ohio, are experimenting with their own bureaucratics. So is the Tennessee Valley Authority. Even the federal government is sticking its toe in the water with plans on the drawing boards for agencies ranging from Action to the U.S. Postal Service.

At Commence, Harman has committed the department to a work improvement effort, beginning with a worker-controlled newspaper and a print shop experiment in which workers redesign their work.

Meanwhile, legislation is pending in Congress - sponsored by Democratic Rep. Stanley N. Lundine, the former mayor of Jamestown, N.Y., and spark plug of the Jamestown experiment - to provide up to $40 million in federal grants for demonstration projects dealing with job preservation and quality of worklife experiments.

Where is it all leading? The UAW's Bluestone, for one isn't sure. "One of the problems," says Bluestone, "is those who are looking for instant suecoss for the parameters within which success can be achieved . . . It's a slow process, and we're only touching the surface." And, in a riposte to Henry Ford, he added. "How do you circumscribe the genius of the mind?"