Adonis Diaries

What message has the Human Factors profession been sending?

Posted on: July 10, 2009

Article 34

“What message has the Human Factors profession been sending?”

In the late 90’s, there have been harsh critical positions on the viability of the body of knowledge and practices of the Human Factors/Ergonomics discipline and profession.  A few human factors scholars/professionals pinpointed the problem as a failure to communicate to engineering designers the content, values, and substantial database that exist for their practical projects; an insensitivity of designers to human factors data. 

A second group of professionals lamented that our research papers have been oriented to basic science and not finding cost-effective solutions to designers’ problems; thus, the inadequacy of our data for solving practical design problems.  A third group advanced the opinion that our methods and body of knowledge are not progressing fast enough to qualify as a science of ergonomics because the studies lack the quality of generality in the findings; engineer designers learned to ignore the quantitative answers of our studies on the basis that their own judgments would probably be equally as good without our research findings.

These positions are valid but we must admit that this discipline is more complex and more difficult than the other engineering fields.  First, there are no design drawings for people as engineers are familiar with because the structure of human organisms is approximately delineated and the mechanisms are imperfectly understood.

Second, people vastly differ in anthropometric dimensions, cognitive abilities, sensory capabilities, motor abilities, personalities, and attitudes; thus the challenge of variability is different from physics where phenomena behave in countable fashions and can be accounted for in design.

Third, people change with time; they change in dimensions, abilities and skills as well as from moment to moment attributable to boredom, fatigue, lapse of attention, interactions among people and with the environment.

Fourth, the world is constantly changing and systems are changing accordingly; thus, interfaces for designing jobs, operations and environment have to be revisited frequently.

Fifth, everyone feels is an expert about human behavior on the basis of common sense acquired from living and specific experiences and we tend to generalize our feelings to all kinds of human behaviors but not so expert in the fundamentals of natural sciences such as physics or chemistry.  We think that we have convictions concerning the effects of sleep, dreams, age, and fatigue; we believe that we are rather good judges of people’s motives, we have explanations for people’s good memories and abilities, and we have strong positions on the relative influence of nature and nurture in shaping people’s behavior.  Consequently, the expertise of human factors professionals are not viewed as based on science.

To remedy the shortcomings and miscommunication of the discipline Alphonse Chapanis suggested that our discipline focus on the design aspects which should separate it from the purely academic disciplines such as psychology, physiology, and anthropology; research should be oriented toward practical designs of what we have to do or want to use.  An example of faulty communication with a group of engineers: instead of talking about our sensory systems as a psychologist do for the concepts of absolute thresholds, upper thresholds, and just noticeable differences a human factors engineer should focus on the machine displays where the energy levels of the beams of electrons striking the phosphorescent surface have to be intense enough to exceed our difference thresholds if we were to perceive them.

An example of uncommunicated message:  a rigorous study was done for a kind of straining work by investigating the mechanical work and energy transfer between and within body segments.  There were human factors messages in the study but the authors failed to recommend any job redesign to reduce the strains and ease the tasks.

An example of research not targeting a practical design: Engineers and programmers are interested in designing symbols for screen displays but when a research investigates the errors and reaction times of graphic versus numeric symbols just to fit a model of information acquisition without any practical design recommendations then we can feel the frustration of designers.

Some basic research could lead to practical design implications and some proclaimed practical research could fail in finding any practical usage and thus the only research that should belong in the human factors literature are those that aim at practical design implications and indeed could recommend practical solutions.  To that end, Chapanis recommended the following:

First, that every submitted ergonomics manuscript should have a final section headed “Design Implications”.  This final section should be objective and be candid about the restricted situations, the trade-off consideration, and the uncontrolled potential variables that might influence the results because engineers welcome partial information and could design on the basis of fragmentary information.

Second, when stating general guidelines about end users hat might prompt a designer to selecting his own wording it is best to suggest the expertise of human factors whom are qualified for selecting the appropriate vocabulary because we should be the experts on user characteristics and task analysis.

Third, the human factors professionals know how to find out what kinds of vocabularies are suited to particular users and tasks; it seems that a vocabulary of less than a couple hundred words, judiciously extracted and tested, was sufficient to design a natural-language dialogue for communicating with intelligent machines.

Fourth, the human factors professionals have to admit that they need further study for design problems because technology changes and systems are being updated continuously.  When asked for specific design recommendations we have to answer that we need to do some study because any engineering practitioner prepare models, simulations, breadboards, prototypes to test, modify, and validate before jumping from a design concept into full-scale operation of a finished product.

Fifth, in practical design work multiple-variable experiments are the exception than the rule.  The ergonomics professionals could tap on many methods in our repertoire such as: activity and task analyses, failure modes and effect s analyses, fault tree, time-line, link, and workload analyses, simulations, rapid prototyping, operational sequence analyses, walk-through procedure and user edits.

As long as the body of knowledge on the abilities and limitations of the human is increasing with the aim of practical design implications of safe, healthy, comfortable and effective systems solutions, then the Human Factors/Ergonomics discipline is an engineering science.  In 1988, Chapanis summarized the state of the ergonomics knowledge and updated versions would be wholesomely welcomed.  There are the “Guidelines for designing user interface software” which contained 944 guidelines, guidelines for the National Aeronautic and Space Administration Standard entitled “Man-system integration”, and other guidelines in the “Human Factors Review”.

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July 2009

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