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What is Human Factors?

Brief History | Forensic Human Factors | Consultants & Expert Witnesses | Additional History

The human factors specialist, or ergonomist, is concerned with fit -- the fit between ourselves and the settings that we occupy, the products we use, and the tasks we are called upon to perform. In a sense, the human factors specialist is kind of a tailor. We tailor products, settings, and tasks to the physical, perceptual, and cognitive characteristics and limitations of their intended users or workers. However, unlike a tailor of apparel whose measure of good fit is appearance, our measure of good fit is performance. If a facility, product, or task is well tailored in the human factors sense, there should be fewer errors and injuries and people should perform associated activities more effectively and efficiently.

Human factors has two parents -- applied experimental psychology and industrial engineering. Historically, applied experimental psychology provided human factors with key concepts and methods for researching and understanding how various attributes of our surroundings affect human performance. In turn, industrial engineering provided the discipline for translating such knowledge into design and operational criteria. However, the formulation of human factors criteria did not automatically result in their adoption. The human factors specialist had to demonstrate the merit of an approach that took human characteristics and limitations into account in the early stages of the design process. In short, the human factors specialist had to be a pragmatist, which meant viewing human factors considerations in the context of other system constraints and performance requirements.

Brief History

Human factors was given its genesis in the World War II military and remained largely tied to the military and aerospace industry until the late 1960's. As the field matured and more colleges and universities offered graduate programs in human factors, the graduates of those programs looked toward expanding the application base of human factors. Their success is reflected by Human Factors and Ergonomics Society's twenty technical groups, e.g., Aerospace Systems; Aging; Computer Systems; Consumer Products; Environmental Design; Forensics Professional; Industrial Ergonomics; Medical Systems and Rehabilitation; Safety; Surface Transportation; Training; Virtual Environments; and Visual Performance.

Forensic Human Factors

While human factors specialists sought to become involved in the early stages of the design practice, in practice, we were often consulted after a serious problem arose in system operation. Given this reality, it was necessary to adopt and develop methods for investigating and analyzing the causes of human error in existing systems. This development did not go unnoticed by attorneys. Indeed, two attorneys, George A. Peters and Richard S. Miller, contributed articles to a special issue of Human Factors (1972, 14(1)) entitled "Human Factors and the Law." Interest in the forensic applications of human factors led to the creation of the Forensic Professional Group of the Human Factors and Ergonomics Society.

The Forensics Professional Group is concerned with the application of human factors knowledge and techniques to "standards of care" and accountability established within legislative, regulatory, and judicial systems. The emphasis is on providing a scientific basis to issues being interpreted by legal theory.
-- 1998-1999 Directory and Yearbook

Members of the Forensic Professional Group frequently belong to the Society's Safety Technical Group as well.

The Safety Technical Group is concerned with the development and application of human factors technology as it relates to safety in all settings and attendant populations. These include, but are not limited to, transportation, industry, military, office, public building, recreation, and home environments. The group welcomes all persons with interests in any area of safety, risk management, and injury/loss control.
-- 1998-1999 Directory and Yearbook

The Human Factors Specialist as a Consultant and Expert Witness

Human factors specialists are usually retained in cases where it is suspected or alleged that injury or death resulted from the failure to consider human characteristics and limitations in task design or in the design, operation, or maintenance of a setting or product. It is a fundamental tenet of human factors that if an accident can be anticipated, then reasonable precautions should be taken to reduce both its likelihood and the severity of its negative consequences.

Typically, the tasks of a human factors specialist who is retained as a consultant are as follows:

Human factors investigations and analyses should be conducted as objectively as possible. Consultants are being compensated for their time, not their testimony. With the prior permission of the human factors specialist, his or her name may be forwarded as an expert witness by the client, who is usually an attorney.

Additional History

Human factors came into being during World War II. Then, as now, humans were viewed as unreliable components in complex systems. Unfortunately, once system failure was attributed to human error that seemed to be the end of it. By contrast, if the cause of system failure was attributed to some mechanical or material defect, considerable effort was allocated to isolating and remedying the problem. This attitude changed somewhat during the Second World War when the costs of human error proved unacceptable.

The military in this country and in Europe brought together psychologists, engineers, physicians, and experts drawn from several other disciplines to improve human performance. The initial attempts by these teams to improve human reliability were consistent with traditional approaches; for example, better techniques for selecting personnel, better training methods, better incentives, and even the use of drugs to enhance vigilance. Indeed, many of these approaches did improve human performance, but the improvements were typically short-lived. Performance degraded as a function of time on task. Perhaps, it was suggested, instead of trying to shape the operator to the characteristics of the system, we should attempt to shape the system to the characteristics of the operator. It was this change in perspective that marks the emergence of human factors in the United Stated and ergonomics in Europe.

After the war, some members of these interdisciplinary teams did not want to abandon either the collaborative effort or the perspective that was borne out of it. In Europe, industry lay largely in ruins, returning soldiers needed jobs, and energy for fueling industry was expensive. As a consequence, many of the available jobs required physical labor. Ex-team members, who would later call themselves ergonomists ("ergo" means work), turned their attention to improving the fit between human physical and physiological characteristics and limitations and the design of hand tools, manual materials handling tasks, and workplaces. Their subject matter included anthropometry (body dimensions); biomechanics (the application of forces); work physiology (the expenditure of energy); and environmental physiology (e.g., the effects of environmental stressors).

World War II helped the United State emerge from a long, economic depression. Unlike in Europe, industry was largely in place and energy was inexpensive. Ex-team members, who would later call themselves human factors specialists or human factors engineers, directed their attention to the kinds of problems that had brought them together in the first place. With the development of high performance jet aircraft, nuclear submarines that could remain submerged for extended periods, and an early warning radar system that could trigger a nuclear retaliatory response, there was little room for human error. Hence, human factors specialists were largely concerned with how people receive, process, and act upon information.

(Portions of the above article excerpted from
Sloan, G.D. "Human factors and premises liability,"
WSTLA Legal Educational Seminars, Chairperson: John Hoglund,
Seattle, May 20, 1994, pages 94-130)

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