Ergonomics | Research & Encyclopedia Articles

Ergonomics is the science of designing machines and environments that are well suited to the people working with them. Ergonomics, or human factors, considers the design of machines, workspaces, jobs, health issues, and the human-machine interfaces. For example, an ergonomic design of an automobile's dashboard means that the controls can be reached easily and that all displays are visible for a range of drivers, whether they are 1.83 meter (6 foot) tall men or 1.52 meter (5 foot) tall women. Since the last decade of the twentieth century, ergonomics has become an important issue in the use of computer technology.

Before the start of World War II, emphasis was placed on conditioning people to fit the machines in their lives. Machines were created, then human beings were trained to operate them according to the machine's requirements; an example of this is training pilots to fly complex airplanes. However, during World War II, machine systems were inexplicably failing. Airplanes with well-trained pilots were flying into the ground with no apparent mechanical failures. Experimental psychologists were asked to analyze the human-machine interface to discover what was going wrong and to make recommendations. In many cases, they found that the machine systems were poorly designed and confusing, even for trained personnel. This led to the redesign of existing systems such as the altimeters on airplanes. Scientists also started looking at how best to distribute tasks, according to what people do best and what machines do best. Eventually, they realized that instead of changing systems after problems were found, they should use their knowledge about how humans process information to design more "people-friendly" systems from the start.

Many scientists have studied the problem of how to allocate separate pieces of a task to humans and to machines, respectively. Ernest J. McCormick, in Human Factors in Engineering and Design (1976), presented lists of what humans do well and what computers do well. In general, he wrote, humans can respond to perceptual changes in the environment. That is, humans can quickly sense low-level changes in sounds, images, smell, or touch. They can store large amounts of information over long periods of time and retrieve pertinent information. When it is necessary, humans can go beyond the information given to react to unlikely events and create entirely new solutions. Thus, human performance can be described as flexible. Although this flexibility is good, it can also cause problems since humans do not exhibit the same response to the same circumstances in every instance. People's responses can vary from one time to the next and can include errors.

By contrast, McCormick's list of machine strengths noted that such devices are good at sensing stimuli outside of the human's normal range ofsensitivity (e.g., X-rays, ultraviolet light, and radar wavelengths). Machines can store and retrieve large amounts of information rapidly and respond consistently to signals. They perform repetitive actions reliably such as putting caps on bottles of soda pop and do not get tired or bored, as a human might under similar circumstances. McCormick believed that an understanding of the relative strengths and weaknesses of people and machines would help designers create more effective systems.

For people who use computer systems, ergonomic design is crucial. Early computer systems of the 1950s and 1960s were extremely difficult to understand and operate. People had to devote much effort to learning how to manage the technology. In fact, operators of the early mainframe computers formed an elite group of men and women who were sometimes referred to as a " priesthood of computers."

As computer technology became more common, it was important to make the technology easier to use by a wide range of people. In the late 1970s, computers evolved to include microcomputers that could be operated by a single person. The first microcomputers were built by their users from components, and users had to write their own programs to make the computer do anything, even play a game. Once the business and education potential for microcomputers was recognized, ease of use became very important. Now, microcomputers are designed for use by store clerks, teachers, business people, students, and children, as well as by people with special needs. These diverse users may not have much training or computer background. This means that the human-computer interface must be carefully designed by user interface designers and ergonomic specialists.

Designers must ensure that the technology is designed with sensitivity to human capacities and needs and that the resulting work environment is safe and comfortable. Ergonomic design considers the physical, psychological, cognitive, and social aspects of the interaction between the human and the machine. Use of computer technology has been associated with several health issues including eye strain, migraine headaches, muscle and body pain (especially backs and shoulders), repetitive stress injuries (e.g., carpal tunnel syndrome) and stress. For example, repetitive stress injuries can be caused by awkward positioning of wrists and hands, extended periods of rapid repetitive motion, and staying in one position for a long time.

Following ergonomic workplace guidelines can help minimize injury. Suggestions by experts include:

• Positioning the screen at or below eye level to avoid muscle strain;
• Reducing glare with glare deflectors and careful positioning of the computer screen;
• Changing lighting to eliminate glare or eye strain;
• Positioning the keyboard low enough to avoid arm and wrist fatigue;
• Using an adjustable desk so that the user's feet are firmly on the floor;
• Positioning the seat back of the chair to support the lower back;
• Taking frequent breaks to stretch shoulders, neck, and wrists;
• Training people to use and understand both hardware and software to reduce stress and fear.

The ergonomic principle of flexibility is important to the design of computer technology. People of different sizes, physical characteristics, and varying preferences need equipment that they can adjust. Taller people usually want their computer screens at a height that shorter people would find uncomfortable. Some people see best with desk lamps; others prefer natural light. Many organizations, including the Social Security Administration, microchip maker Intel, and retailer L. L. Bean, have implemented ergonomics programs. These programs include new equipment, workspace design changes, and training programs. Employees learn how to create healthy work environments by adjusting desks and chairs and taking frequent breaks. Companies implementing such programs find they can greatly reduce productivitylosses due to work-related injuries.

Terri L. Lenox

Keyboard; Microcomputers.

McCormick, Ernest J. Human Factors in Engineering and Design. New York: McGraw-Hill, 1976.

Shneiderman, Ben. Designing the User Interface: Strategies for Effective Human-Computer Interaction. Reading, MA: Addison-Wesley, 1998.

Wickens, Christopher D. Engineering Psychology and Human Performance. Glenview, IL: Scott, Foresman and Company, 1984.

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