Ergonomics - edited study book -

Hungary-Croatia IPA Cross-border Cooperation Project
"Health and Work Project"

Balazs Pankasz

Ergonomics

edited study book

1

Introduction

Ergonomics is a concept that Western-Europe has long been familiar with. Lately it is
becoming widely known in Hungary too, it appears in the media, and it is becoming part of
advertisements and product manuals. If something is said to be ergonomic that has a positive
connotation, even though we rarely know what the expression really means. The label
ergonomic is to be found on various products and it means a definite benefit in the
competition. At the same time though such concepts as design, usability, user-friendly and
ergonomics get mixed up in people’s minds. This is also why this study fills a gap, as it shows
in five chapters what ergonomics deals with, what ergonomic design means, and what a
successful product is from an ergonomic point of view. The different chapters deal with
current trends and phases of ergonomics, such as the designing of computer hardware and
software, or the fulfilling of the special strata’s – e.g. physically challanged, pregnant women,
children – needs. The chapter on office ergonomics is an example of complex ergonomic
solutions, as it takes many aspects into consideration (aspects like the designing of
workstations, the importance of how things are arranged in a given space, the noise, the bad
climate, or the bad lighting).
So this study might be filling some gap, but it has had antecedents. In Work
psychology, edited by Sándor Klein and published in 2004, there is a separate chapter on
ergonomics by Miklós Antalovits. This chapter describes the basic concepts and main phases
of ergonomics, and even shows through an example what the ergonomic aspects are when
designing a product. So the goal of this study is to continue the work that Sándor Klein has
begun, with the help and presentation of new approaches and the latest foreign literature of
the field.
As for the structure of this study, it can be divided into five larger sections. In the
theoretical introduction the main phases of ergonomics will be described, together with the
dominant issues of each phase. In the first phase of ergonomics the main interest of
researchers was the senso-motoric level of the human-machine interface: their concern was
how to design the screens and operating-boards of machines so that it meets our knowledge
about human movement and perception. The next phase was defined by systems theory,
which inspired various different sciences: surpassing the human-machine interface, experts of
ergonomics started to observe the whole system of human-machine and surroundings. In the
third phase ergonomics becomes a benefit in the competition on the consumer market of
products. What is ergonomic sells well, so ergonomic design becomes a priority for

2

enterprises in the 1970s. In the 1980s cognitive ergonomics redefines classical ergonomics. It
is still about the human-machine interface, but the now more complicated machines raise the
following problem: how to fit human and artificial intelligence together? From the 1990s
product ergonomics is still a leading branch of ergonomics, aspects of safety become more
important, new methods appear on the scene (for example the involvement of future
consumers in the process of designing), and the designing for those with special needs gains
more ground. Looking at the chronological evolution of ergonomics it becomes clear that
ergonomics is a new science, the focus, goals and methods of which are constantly changing
and developing. The recognition of ergonomics has changed significantly, although the
spreading of concept does not necessarily coincide with the exact interpretation of the
concept. The part on the methods and the criteria of a good product shows the complexity of
the fitting of human, machine and system in which not only human factors play a great role,
but other, e.g. engineering or economic aspects as well.
In the second chapter of the study the problem of the human-machine interface is dealt
with in detail. On the one hand it refers to the classical ergonomic problem about “handles
and scales”. How to construct the operating-boards of machines and instruments operated by
people? In this same chapter another issue is dealt with at the same time: that of a new level of
interface: the encounter of human and artificial intelligence. The central issue of the field
called cognitive (and software-) ergonomics is how to fit the higher human thinking (such as
decision-making, judgement passing, creativity) and the artificial intelligence to each other.
Obviously the experts mainly examine the communication between human and machine in
relation to computer softwares. With the spreading of personal computers ergonomics has
entered a new phase in terms of methodology as well, as the involvement of the users at an
early stage of the designing, the so-called ’from the bottom up’ projects are more widespread
now.
In the third chapter the field where the common man mostly encounters ergonomics
will be dealt with: that is the people-centered designing of everyday, either in- or out- of work
objects. Nowadays, if a product can be called ergonomic, it raises its value directly while it is
not clear what is considered good ergonomic designing. Is it the user-friendly nature of
something, or the usability? The”good” shape or the function? In the third chapter first the
cycles of the product-designing will be introduced, then those aspects that make a product
good from the point of view of human-product fitting. Here two independent, but very closely
related approaches will be discussed: on the one hand the concept of usability drawn up by
Schakel (1981) which is often referred to with the acronym LEAF (Learning, Efficiency,

3

Affection and Flexibility). The other approach is associated with the name of Antalovits
(1998) who defines the ergonomically good product on the basis of three criteria: efficiency,
safety, comfort. The next part of the chapter is set out to find the answer to the question which
designing strategies lead to usable, well-fitted products. It is important to emphasise that
designing strategies can be put in an order on the basis of the probability of their leading to an
ergonomically good output, but the choosing or dismissing of a strategy depends on more than
one factors. For example the ergonomically good strategy is not always satisfactory from an
economic point of view, and the experts of development always have to look for compromises
among the factors. At the end of the chapter the issue of software-ergonomics will be dealt
with: what makes the using of a software easy for a user?
In the fourth chapter the advantages of the approach that takes human factors into
consideration will be described through a practical example. Office ergonomics uses the
results of various ergonomical researches. In the process of designing an office surroundings,
such factors should be taken into consideration as environmental effects (as noise, lighting,
climate, temperature), or issues arising from the nature of the work done (for example because
of the long-term sitting the adequate design of chairs and tables is important, and the usage of
computer raises many questions like the exhaustion of the eyes, the possible damage of wrists
and hands). The design of the office surroundings is in close relation with the preservation of
the employee’s health: the injuries and illnesses of intellectual occupants are related to static
work to a great percentage, the constant usage of the mouse and the keyboard, the staring at
the monitor for a long time that is, to things that ergonomic designing can reduce a great
amount, or even eliminate.
The fifth and at the same time the last chapter of this book sets out to find the answer
to how ergonomics tries to meet the needs of “special” consumers. The term “special” in
relation to ergonomics can refer to many different aspects: maybe it is just applied for
consumers who are too short, too tall, too thin or overweight, or their dominant hand is the
left one. Pregnant women, elderly people and physically challenged people are also
consumers with special needs. The challenge of ergonomics here is that the basic human
information that ergonomics uses during the process of designing is different in their case.
The products, instruments and work surroundings have to be designed in a way that the fitting
of human, machine and surroundings could be realized in the case of these consumers with
special needs too, while aspects of efficiency still should have a priority. Even in the case of
such an everyday product as a bath it is evident that elderly people have to face different

4

problems than average consumers while using the product: getting in and out, temperature
regulation is a different challenge for them than for the younger ones (Nayak, 1995).

Hopefully this review reaches its goal: the concept of ergonomics and issues of
the field observed give an elaborate introduction for the reader who encounters the subject for
the first time.

5

Chapter One: The Concepts, Phases and Methodology of Ergonomics. What is Good
Designing Like?

Has it ever happened to you that you could not heat your coffee in a microwave oven?
In the picturesque anecdote of Normann (1988) this is what happened to Kenneth Olsen, Msc
in engineering, president of Digital Equipment Corporation (DEC) with the oven made by his
own company. Or that you turned on the wrong hot plate as it was not evident for you which
switch belonged to which hot plate? Perhaps that after hours of typing your wrist hurt
because of using the mouse, your back ached because of the uncomfortable chair, while you
were sick and dizzy because of the exhaustion of your eye-moving muscles? Are you familiar
with the unpleasant feeling when an object, a instrument is too small, too big, has too many
or not enough programs, or when it is impossible to tell what the purpose of certain softwares
is?
It is too often experienced that the objects surrounding us are like the Procrustean 1 bed
that we just cannot fit into. The science of ergonomics is set out to find the answer to how a
better fitting of the person, the objects and instruments used by him and the (work)-
surrounding could be reached. The emphasis being on the setting and the securing of the
harmony between the person and the technical surrounding (Antalovits, 1998).
The term ergonomics comes from the combination of two Greek words: ergos means
work, and nomos means laws. The expression is generally attached to the name of professor
K. F. H. Murrel (1965), who was one of the scientists who gathered together in room 1101 in
Hotel Queen Anne in London on July 8th, 1949 with the purpose of founding a team that dealt
with the human performance (”Human Performance Group”) (Pheasant, 2003) 2. These
scientists came from very different fields of science: there had been an engineer, a
psychologist, a physiologist, a doctor and even an industrial safety specialist. During the
Second World War, which had only just ended recently, they all had been involved in
researches about the efficiency of the fighting man, and they all had realised the complex
relationship between human and machine. They had founded the Ergonomics Research
Society before the end of 1949, which later changed its name to Ergonomics Society. In the

1
Procrustes is from the Greek mythology. He was a notorious thief, who laid his victims in his bed and tortured
them: if his victim was of high stature, too long for the bed, then he cut them shorter; if the victim was too short,
he stretched them until they reached the two ends of the bed. The “Procrustean bed” is a well-used term in
ergonomics and it refers to solutions that most actual consumers could only be forced into.
2
It is important to note though that the phrase was first used in a Polish newspaper in 1857. But apparently
Murrel did not know about this first usage of the word and he suggested the adaptation of the term ergonomics as
a name for the new branch of science independently (Harvey, 2004).

6

chapter about the history of ergonomics we will see that the issues in ergonomics have a long
list of antecedents, nevertheless it is safe to say that ergonomics was born in the Second
World War. During the war the American Air Force had lost more than 400 airplanes because
of errors that originated in the misplanning of the ”meeting” of human and machine
(Antalovits, 1998). The management of the army and the designers of the machines had no
other choice but to face the fact that even though the machines were technically improved,
they knew more, the whole system became less reliable. The problems were the results of
ignoring the people who managed the machines during the process of the designing of the
machines, and the basic laws regarding the human perception, detection, way of acting and
way of processing information. The damages caused by the war were dramatic indicators of
an earlier just perceived truth: the machines and the work surrounding have to fit the human
consumer. In the absence of optimal fitting there are various consequences: the performance
lessens, user frustration escalates, the probability of accidents escalates, and there is physical
and mental health damage is to be expected (Pulat, 1992). This is the first examined issue of
ergonomics: the encounter of human and machine on the level of perception-motion. What the
display or user interface of a machine should be like, which operations are natural and which
are unnatural for people? How to meet human needs and improve efficiency of the machines
at the same time? As these questions suggest, ergonomics is a practical science the goal of
which is to “scientifically observe the interaction between human and his work surroundings”
(Murrell, 1965). The task of ergonomics is to collect the basic information about people
necessary for planning, as well as to provide an independent methodology for this process. In
order to be able to observe people we often opt for the analogy of the information processing
system which in the case of human beings consists of inputs, intermediate processes and
outputs. Inputs are the stimuli coming from our surroundings which we either react to or
ignore. Between perception and procession on a higher level there is cognition and attention.
What happens on a higher level is often simply referred to as “thinking”. This involves such
processes as decision making, problem-solving and creativity. All these human cognitive
processes are permeated by memory, short term work-memory as well as long-term memory.
At the end of the process there usually is some motoric reaction, action. Like any other
models, this is also a significant simplification 3 but it helps to illustrate what types of
information should be taken into consideration when designing for humans 4 (Noyes, Garland
and Bruneau, 2004). The model shows that the characteristics of perception, cognition,

3
Ignores important, interaction-modifying human factors such as emotions.
4
This is also called “human-centered design” (Harvey, 2004).

7

attention, “thinking”, memory and motoric relations are primarily interesting for researchers
of ergonomics. Afterwards the specialists who put ergonomics into practice – primarily
engineers – will try to design machines and systems adapted to human features based on this
basic information5.
As it has already been mentioned, the first issue of ergonomics was the adequate
planning of the encounter of human and machine, the human-machine interface, on a sensory-
motoric level. During the practical appliance of the new science though it became clear that
there are several other issues that the experts of ergonomics could contribute to in merits.
Besides, quite a few “ergonomic” issues only arose after the birth of this branch of science.
The chronological evolution of ergonomics will be followed through in the first part of the
introductory chapter, beginning with the antecedents of ergonomics and finally arriving at
today’s trends. The periodization does not mean though that a given issue had only been
interesting to the scientists in the given period; simply these issues arose in this order. For
example ergonomics specialists still seek for solutions of the human-machine interface on a
sensory-motoric level. This is well-indicated by the researches on different ergonomical
keyboards and mouses. The following figure about chronology shows what periods
ergonomics has gone through (Fig. 1.).

Figure 1.: Periods of Ergonomics (after
Antalovits, 1998)

5
It is worth noting that according to Antalovits (1998) only those solutions are ergonomical where one part of
the specialists involved come from fields dealing with the human being (e.g. psychology, biology, medical
sciences), and the other part of them has Ms in engineering.

8

Antecedents of Ergonomics: Industrialization, Work-Organization by Taylor

The roots of ergonomics date back to the beginning of the century, the era of
industrialization, the era of large-scale technologies (Antalovits, 1998). Primarily the
scientific management movement created by Frederick Taylor is worth mentioning, the
primary goal of which was to rationalize work6 (Taylor, 1911). He did this with the help of
such methods as movement- and time analysis. Although there had been some forward
pointing discoveries (e.g. Frank and Lilian Gilbreth’s researches on sergeants In: Antalovits,
1998), the ergonomic approach was alien to current notions. In Taylor’s thinking, for
example, the relationship among machines, instruments and men played a significant role, but
here the idea was to find the right person for the right job, or that it is the person that should
be adjusted to the machine. Dekker (2004) points out the differences well in the light of
human errors between pre-ergonomics- and ergonomic thinking. Human errors had been seen
as the reasons for the collapse of systems before ergonomics appeared on the scene. People
were seen by engineers as the only unstable points of a system: the instruments, machines and
system in reality would work safely if it was not for the unpredictable human thinking. The
ergonomic approach sees human errors not as reasons, but as symptoms that indicate a deeper
error somewhere in the system. The error here is a planning error: simply during the process
of planning the peculiarities of the people who operate the machines had not been evaluated
correctly, or had not been evaluated at all.

Figure 2.: Classical and Ergonomic Approach of Human Errors
One important reason for the change in the approach is shown by Noyes (2004). In
most of the factories in the 19th and in the first part of the 20th century humans were the
“sacrificable” elements of a system. The human workforce was not particularly valuable as
most of the jobs did not require any special qualifications. If somebody dropped out of work –

6
This movement became known as taylorism.

9

either because they got hurt or because they died – they were easily replaceable. The worker
hired to his place learned the mostly manual work quickly. It is easy to see then that before
the Second World War, save for a few sporadic exceptions, there had not been an ergonomic
approach, though the appearance of one is not even justified yet 7. The situation changed in the
Second World War when it turned out that handling of the advanced technologies (e.g. radar
screen, operators and displays of instrument panels of airplanes) was a challenge for the
operators. Many of the operators found it hard to learn the application of new technologies
and especially at the early stages of the learning process made mistakes, often with grave
consequences. It is possible that at a time of peace this would not have mattered so much, but
during the war educated workforce was increasingly appreciated: while there was no time for
elonged trainings, the lack of trainings claimed financial and human sacrifices. The
experiences gained during the Second World War made it clear that the needs and the abilities
of human operators (e.g. pilots, navigators) could not be ignored in the process of planning
the new technologies. This realization gave birth to the first, “classical” phase of ergonomics,
which is also referred to as the ergonomics of “handles and scales” (Antalovits, 1998). This
phase will be described in the next section.

The Birth of Ergonomics (1945-1960): Human-Machine Interface on the Sensory-
motoric Level
As it has been mentioned before,3the Second World War showed the challenges both the time and
Figure 3. Altimeter with indicators. Grether (1949) demonstrated that
the accurcy of its reading was a problem for the pilot.

7
During the First World War there already had been a shift from the early industrial approach that ignored
human factors towards an ergonomic approach. It is Oborne (1982) who draws the attention to the fact that in the
cartridge factories women could not operate the machines traditionally designed for men so efficiently.
Engineers realized though that the problem was not with the women, but with the designing of the machines.

10

dramatically in relation with the design of the human-machine interface (where human
was in close contact with the machines) (Grudin, 2008). During their application many
solutions turned out to be far from the optimal. Grether’s observation (1949) demonstrated for
example that the traditional altimeter with three indicators which were used on war-planes
too, not only distracts the pilot’s attention for too long – it took more than 7 seconds just to
read it –, but in 12% of the readings the pilot was more than 300 metres out when defining his
altitude. Grether (1949) proved that a different design lessened the time spent on reading the
altimeter while the accuracy of the reading improved. The difference between the traditional
and the different design was that while the first ignored the “human factors” the second took
that into consideration.

A little detour is necessary because of the term “human factors”: this name became
widespread after the Second World War in the United States of America. Its researchers and
practical experts dealt with similar issues as the specialists of ergonomics in Europe, although
there were slight differences between the two approaches. The scientific background of the
experts dealing with human factors in The States was less diverse than in Europe. The team
engaged in human factors had been formed inside the American Psychological Society in
1957 and it was only later that it became an independent society called “Human Factors
Society”. The European school, as we have already seen, was much more marked by
diversity, as already in the first meeting in 1949 next to the psychologists biologists,
physiologists, doctors and engineers were represented. From now on though the terms
ergonomics and human factors will be handled as synonyms, which coincides with the
practice of recently published specialized books (Antalovits, 1998). This change is also
reflected in the fact that the Human Factors Society founded in The States has recently altered
its named, and now it is called Human Factors and Ergonomics Society (Stanton, 2003).
It is evident from the chronology that experiences of the Second World War started
both in the United States of America and in Europe those researches, research laboratories
that sought to solve the issue of the human-machine interface. Logically the army played host
to the first research laboratories: in The States the Ministry of Defense started the
MANPRINT8 program which wanted to solve the issue of the human-machine integration. It
was not long after that the Ministry of Defense in the United Kingdom announced a similar
program (Harvey, 2004). In the meantime the Ergonomic Research Society was formed in
1949 in the UK, then in 1957 the first ergonomic periodical, the Ergonomics was issued too.
8
MANpower and PeRsonnel INTegration.

11

In 1959 the “International Ergonomics Association” was established, which held its first
conference in 1961 in Stockholm (Antalovits, 1998). What was essential then was the
recognition that the not optimal – suboptimal – operation of certain war instruments derived
from the ill-fitting of human and machine. The consequences of this ill-fitting were
substantial for the army: there was either a need for elonged and expensive training for the
application of the instruments, or in the lack of these the weapon-systems could not reach
their planned parameters (Harvey, 2004). On the sensory-motoric level of the human-machine
interface researchers and practice-specialists have to consider two problems: in what form
should the machine give signs, share information with the operator (screen), and what
operating-board should it have (control). The ergonomic connections that have been explored
in this field will be discussed in detailed in chapter two, the subject matter of which is the
sensory-motoric and the cognitive fitting of the human machine interface.

System ergonomics (from the 1960s): Examination of Human-Machine-Surroundings
as a System

Throughout the 1950s the development of ergonomics was steady thanks to the
military preparations of the cold war and the space research contest. It was in this tome that
general systems theory was born (see e.g. Bertalanffy, 1950), which had a fertilizing affect on
many fields of studies, ergonomics among them. Ergonomics got away from the problem of
the human-machine sensory-motoric interface and began to think on a level of systems about
the relationship of human, machine and surroundings. It was also during this time that big
companies recognized ergonomics’ – mainly economic – potentials, which gave a head start
on ergonomics’ military technology-, and space research-free development 9. Throughout the
1960s human factors were utilized not only in the designing of machines and technical
instruments, but they also played a great part in the designing of surroundings and
optimalization of production systems (Antalovits, 1998).

Product ergonomics (from the 1970s): The Ergonomics of the Designing of Products

Product ergonomics is practically the joint segment of industrial design and
ergonomics (Antalovits, 1998). In the 1960s big companies recognized the direct economic
9
Although it still stands that the discoveries of ergonomics almost always appeared first in high-technology (e.g.
Military technology, space research) (Antalovits, 1998).

12

advantage of ergonomics after
the revelation that it is not only
the optimal design of machines
and instruments, but also of the
whole work surroundings that
has an effect on the
performance of people and so
this also effects the efficiency
of the company. In the 1970s
ergonomics’ usefulness and its
ability to directly produce profit became even more evident for the companies. Amid the
intensifying competition of the car industry, consumer electronics and companies producing
consumer products it was discovered soon enough that most operators of a market can offer
the same quality for the same price. Consumers chose from the many similar products based
how much those met their individual needs. The assertion of the ergonomic aspects of a
product throughout its whole life cycle (starting from the raising of the idea, throughout its
realization and its introduction to the market, until the recyclebility) had a significant effect on
how well the product sold. According to Noyes (2004) the sooner human factors are taken
into consideration while designing, the ”better” the product will be from the ergonomic point
of view (it will be discussed at the end of the chapter what makes a product or design “good”).
Different aspect of product ergonomics will be discussed in detail in the third chapter of this
study.

Cognitive- and Software-Ergonomics (from the 1980s): Expansion of
Computerization, the Introduction of PCs. Human-Machine Interface on a Cognitive Level.

In the 1980s researches on ergonomics had two significant driving forces: one of them
was the widespreading of information technology – and especially that of personal computers.
The other one is connected to those major catastrophes which happened close in time at the
end of the 1970s and the 1980s (in 1979 the accident in the nuclear power plant of Three Mile
Island, in 1984 the disaster in the chemical plant of Bhopal, India, in 1986 the Chernobyl
disaster, in 1986 the crash of the spaceship Challenger and in 1987 the accident of the ferry
Zeebrugge).

13

Figure 4: Nuclear Power Plantation of Chernobyl

The invention of the silicone chip and the widespread of computers opened a new
chapter in the history of ergonomics: researches on cognitive and software-ergonomics
(Hendrick, 2002). This new aspect raised the importance of ergonomics in general as
according to the estimations of Hendrick (2002) the number of ergonomic positions increased
by 25% in the 1980s, in the market sector. The widespread of personal computers drew the
attention on a daily basis to the importance of designing hardware and software keeping
human factors in mind. The encounter of human consumers and computers was nothing else
but the reformulation of the first, classical ergonomic problem – the sensory-motoric fitting of
the human-machine interface – on a higher level: the fitting of the human-machine interface
on a cognitive level. This is the level that has formally been defined as “thinking” after Noyes
and his co-workers (2004): mental working capacity, decision-making, communication of
human and computer, creativity and similar phenomena included here.
The effect of the accidents and disasters were twofold: Antalovits (1998) pointed out
that over the analysis of the reasons of the catastrophes the conclusion was made that one
common reason was discovered behind all disasters. This was the under-valuation of human
factors – nay, their ignorance in some cases – amid the designing and operating of the
systems. Similarly to the widespread of computers the accidents helped to reinforce the
position of the study of ergonomics too as the keeping of ergonomic aspects in mind was now
passed into law in more and more contrives, or the already existing laws were aggravated.
According to Hendrick (2002) the practice of the juries of the United States of America was
clear and consistent in this field: it is the responsibility of the leaders that they payed enough
attention to the ergonomic aspects in the designing of their products as well as in the design of
their work surroundings. In the absence of this they would have to face serious penalties. In

14

relation with the accidents the researchers arrived at a shocking discovery which consequently
lead to a subfield of ergonomics, macro ergonomics becoming more important: it is absolutely
presumable that the engineers – from an ergonomic point of view – do an excellent job in the
process of designing of the parts, modules and subsystems of a given system, but they still do
not reach the desirable efficiency and safety. The reason of this is that they do not pay enough
attention to the macro ergonomic designing of the whole work system 10 (Hendrick, 1984,
1986a, 1986b). The analysis of the disasters (primarily in the case of the accidents in the
nuclear power fields of Three Mile Island and Chernobyl, and in the case of the disaster in the
chemical plant of Bhopal) many of the researchers have arrived at the same conclusion
independently from one another (Meshkati, 1986, 1991, Meshkati and Robertson, 1986,
Munipov, 1990).

Trends in Ergonomic Research
Ergonomics is a young science which is under constant development and change as
new problem arise every day in relation with the encounter of human and machine and human
and work surroundings. The speed of changes is shown clearly by the fact that today
software-ergonomics is one of the most important parts of the human factors researches, while
the first personal computers were only sold in February 1978, and the widespread of the
personal computer sin the workplace only went through at the beginning of the 1980s (Noyes,
2004).

10
This seems as if system ergonomics got more important, but according to Hendrick (2002) it is not only this,
but a change in the approach as well: while system ergonomics examines the fitting of the individual and the
work surroundings primarily and serves as a kind of environmental ergonomics, macro ergonomics lays stress on
the fitting of human and the whole system, work system.

15

Figure 5: One of the first personal computers, Xerox Alto in 1973

It is expected that in the future the previously described trends will get stronger:
cognitive- and software-ergonomics, as well as the safer designing of the work surroundings
and the products too. Software-ergonomics changes, alters the methodology of ergonomic
researches, as it is different in its nature from the previous issues concerning human factors.
Since in the case of softwares there is no average consumer, as personal computers are present
in almost all of our lives. During the process of programming such softwares have to be
created that meet the criteria of optimal fitting in the case of beginners as well as advanced
consumers. Another important factor to be kept in mind in the process of the designing is that
engineers and IT experts have to forget the traditional ”from the top down” design, as the
success of a given software is realized if the consumers is initiated as soon as possible, and
participation is possible (Antalovits, 1998). As we learn more and more about people – the
basic information that are characteristic of people – and the operation of machines and
instruments, it is to be expected that the development of “instruments”11 will be more
differentiated, and special- or stratum needs will be taken into consideration more.
It has been mentioned before that ergonomics is a study with its own methodology,
where the task of researchers is, through the collection of basic information, to contribute to

11
Using the term product in the broad sense of the word.

16

the harmony between human and machine. The methodology of ergonomics will be described
in the next chapter.

The Methodology of Ergonomics
A part of the methodology of ergonomics coincides with the methods of other studies
about human beings, while there are some special procedures worked out by ergonomic
researchers (such as the heuristic evaluation). In this part we will describe the different
methods, how they can be grouped, all the while stressing the advantages and disadvantages
of each method.
The first big dimension along which ergonomic methods can be grouped according to
Noyes (2004) is the differentiation between formative and summative methods. Here what
makes the difference is that one method can be applied in a given part of a product’s life
cycle. Formative procedures are applied in the process of the designing of a product, while
summative procedures are more suitable for the analysis and evaluation of finished product.
This difference is often shown through the following, picturesque example: “when the chef
tastes the soup while making it that is formative evaluation, when the guest of the restaurant
tastes it that is summative evaluation”. It is important though, that most of the 25-30
methods12 in the methodology of ergonomics can be applied both in the process of the
designing of a product and after it has been introduced into the market.
Another aspect is the objectivity of the methods. Subjective are the methods where the
measuring is indirect. It is the consumer who is asked to relate his/her impressions and
experiences in some form. While subjective methods are suitable for the measuring of
consumers’ attitudes primarily, objective methods apply direct measurements and give more
objective results. Before a more detailed description of these procedures 13, let us see in chart
1. The most important subjective and objective methods14.

12
According to Noyes (2004) the number of methods depends on how much we differentiate among the
particular procedures. The group of methods called task analyses for example stands for 100 more or less
different procedures in reality.
13
During the description of the methodology such general procedures that most human sciences apply, as
questionnaires, interviews and laboratory examinations will not be elaborated on, for there are many
methodological summaries available on these (e.g. Howitt and Cramer, 2000 book of methodology).
14
For simplification in Chart 1. empirical methods (laboratory methods) are listed among objective methods,
although these are often differentiated along the control dimension (Noyes, 2004).

17

Subjective Methods Objective Methods
Heuristic Evaluation Observation
Check list Task analysis
Focal groups Human Reliability Assessment
Questionnaires Examinations in laboratories
Interviews

Chart 1.: Subjective and Objective Methods in Ergonomic Researches

Subjective Methods
Subjective methods operate with data based on indirect accounts given by consumers.
Among others, the heuristic evaluation, the check list, focus groups, questionnaires and
interviews belong here. Most of the subjective methods can be categorized as “fast and dirty”
(Noyes, 2004). As the term suggests, information can be collected fast through these methods,
but they do not reflect on the question “why?” that would give reasons so much, and mostly
the validity and reliability of the data is questionable.

Objective Methods
Instead of consumers’ attitudes objective methods operate with directly measurable
data. Observation, task analysis, Human Reliability Assessment and controlled laboratory
examinations belong here.

Objective Methods 1: Observation
The observation of the consumers without a doubt hold the advantage that it gives a lot
of information for the experts of ergonomics that the predicting of which would have been
hard – or impossible – without the observation. The image validity of this method is very
strong, which means that it provides reliable information on what the consumers actually do
with a product, or an instrument. Noyes (2004) quotes an observation examination of a
colleague, Chris Baber: Baber and his co-workers observed at a London Tube station how
people used the ticket vending machines. It was a shock for the researchers that many people
tried to fit notes into the spot made for coins. This type of appliance is hard to detect from the
design office, still it might be a real difficulty during the operation of the product. This is
where the advantage of the method lies: may the utilization of a product be weird, it will be
found out during the observation. The disadvantages of this method are:

18

• The reason of the attitude is not revealed
• The control of the observer is low
• Ethical issues arise
• It is time-consuming and
• The effect of the observation on the observed is uncertain

One of the most serious problems is that although the observation shows what it is that
the consumer does, it does not show why they do it. This can be a problem mainly during
redesigning. To stay with the Barber-problem: it was clear from the observation that
consumers tried to put notes into the coin spots, what was not clear was what feature of the
vending machine got them confused. Is it possible that it is not clearly indicated that the given
spot can only hold coins? If this is the reason behind the attitude, how should the machine be
altered? Questions like this cannot be answered with the help of the observation method. A
possible solution could be to ask the consumers after the observation why they did what they
did, but in most natural observed situations this is hardly feasible. The following problem in
relation with observation is twofold: it is difficult to follow through and evaluate events in
real time, so observation has to be recorded (usually audio- and video recordings). But the
recording raises ethical questions: if the observants are not warned about the observation, is it
legal to record them? But if they are warned that might change the nature of the observed
situation, as has shown the researches between 1924 and 1932 made by Hawthrone. In
Hawthrone’s researches the observed workers still did a better job than their non-observed
colleagues when their work situation worsened (Noyes, 2004)15. The ethical question apart,
another problem with the recorded observations is that they are very time-consuming:
according to some estimations one hour of video observation would take ten hours of
processing to make a report useful for further analysis (Noyes, 2004).

Objective Methods 2: Task Analysis
Task analysis in reality is an umbrella term for various, more or less similar techniques
(Noyes, 2004). According to Pheasant (2003) good designing projects almost always begin
with task analysis, so in this respect task analysis is a formative method. Task analysis in his
opinion is a formal, or mostly formal experiment for defining what will the consumer,
operator actually do with the product or system. Task analysis determines the desirable result

15
This is a problem with the laboratory experimental methods as well.

19

of the instrument- and system appliance, the physical operations the consumer will have to
perform to reach that output, and processing requirements of the information relevant of the
task as well as the environmental compulsions. One of the most applied task analysis
techniques is hierarchical task analysis where the task is subdivided into goals and sub goals.
The result of the task analysis is often some sort of visual illustration, for example a flow
chart (Noyes, 2004). One of the main advantages of the method is that by systematically
breaking down the task it becomes clear where the consumers have problems in relation with
the instrument or system. One of the issues is that it is difficult to determine the ideal level of
the division of the task, and that it is difficult to acquire this technique for the inexperienced
researchers and practical experts16.

Objective Methods 3: Human Reliability Assessment (HRA)17
Methods suitable for determining the reliability of humans (HRA) are special cases of
task analysis. Their goal is to identify the errors that arise during the different types of
consuming. Generally speaking HRA focuses on measuring the consequences of the different
errors this way contributing to their prevention, the reduction of negative outcomes and the
handling of errors. In the course of HRA analysis an event-tree, or error-tree is made. It is
common in both methods that they show the errors, the ways of recovery from the errors, as
well as the probability of the occurrence of an error (Kirwan and Ainsworth, 1992).

Objective Methods 4: Controlled Laboratory Examinations
Laboratory examinations are often listed as a separate category, differentiated from
both subjective and objective methods. They differ from the previously described objective
methods in their degree of control: during a laboratory experiment researchers can exclude a
whole series of variables, in order to arrive at casual correlations as clean as possible. As it
has been mentioned in Pheasant (2003)’s opinion a designing project that takes ergonomic
aspects into consideration almost always begins with task analysis. What is essential is that
the end of the process is the consumer’s test, which can be seen as an experimental method. It
is nothing but the testing of a prototype among controlled conditions. According to him it is
important to select the participants well and to ensure that the test group consists of people
that represent the target audience of the product18. Noyes (2004) claims that usability is in the
16
The problem is to decide which is the most appropriate method for a given analysis from among the various
different task analyzing methods.
17
Human Reliability Assessment.
18
Sometimes though, as an alternative, it might be relevant to test the product on people that we know in
advance will have problems using the product. If they are able to operate the product efficiently, then the

20

focus of controlled examinations. This aspect will be discussed in detail at the end of the
introduction, so now we will only describe it shortly: in Shackel (1981)’s definition a product
is usable if it is easy to learn, efficient, flexible, and the consumer likes it (this is the
subjective component of usability) 19. These aspects of usability are best tested in laboratories.
The disadvantage of the experimental techniques is that they presume preliminary training,
needs significant preparations and is fairly expensive. In many cases its everyday validity is
questionable too, as between laboratory and real situations there are relatively big differences.

So far ergonomic methods have been divided into summative and formative types, as
well as subjective and objective methods. Stanton and Young (2003) enlist further aspect
according to which methods can be grouped. These are:
• In which part of the product’s life cycle could the method be applied20
o Can be applied for analyzing a concept (the first part of the designing of a
product). For example: check lists, interviews, heuristic evaluation.
o Can be applied for analyzing the design (when a certain written description,
material already exists about the product). E.g. hierarchical task analysis,
analysis of the task that makes the identification of the error possible,
predictive human error analysis, and usually the analyses of the previous stage.
o Can be applied for analyzing the prototype (the period before the product’s
introduction to the market, when the product already exists either as a
computer simulation or as a constructed prototype). E.g. observation,
controlled laboratory analysis, and usually the analyses of the previous stages.
o Can be applied for analyzing operations (after the product’s introduction to the
market, the period of application and maintenance). E.g. field-work, and
usually the analyses of the previous stages.

• The time the analysis consumes21

consumers considered more ideal will presumably be able to do so too (Pheasant, 2003).
19
Very often the aspects of usability determined by Shackel (1981) are described by the acronym LEAF. LEAF=
learnability, effectiveness, attitude of the user, flexibility.
20
This aspect corresponds to the differentiation between formative and summative methods, but Stanton and
Young (1999) expounds on the usability of the different methods in the different life stages.
21
Time actually consumed always depends on the subject of the analysis; however the relative need of time of
the methods is indicated well in this disposition. Long as it may be, a check list that is faster than the interview
technique or an interview technique that is faster than hierarchical task analysis can be designed.

21

o “Not enough” time: check list, observation, questionnaire, design analysis,
heuristic evaluation.
o “Some time”: modelling on a key-stroke level, link analysis, check list,
observation, questionnaire, method of weighted nets, design analysis,
interviews, heuristic evaluation.
o “A lot of time”: modelling on a key-stroke level, link analysis, check list,
predictive human error analysis, observation, questionnaire, hierarchical task
analysis, method of weighted nets, task analysis that ensures the determination
of the error, design analysis, interviews, heuristic evaluation.
• The output measured during the process of analyzing
o To measure errors: task analysis that ensures the determination of the error,
observation, predictive human error analysis.
o To measure time: modelling on a key-stroke level, observation.
o To measure usability: check list, questionnaire, hierarchical task analysis,
interviews, and heuristics.
o To measure appropriateness of the design of the product: link analysis, check
list, predictive human error analysis, task analysis that ensures the
determination of the error, design analysis, heuristic evaluation.

After the introduction and grouping of the methods the question arises which method
is better than the other? The answer to this question will be searched after in the next part of
this chapter.

Which Method id Better?
This is not a yes-no question as the usefulness of the methods depends highly on:
• What is the reason of the measurement, evaluation?
• What are the characteristics of the given product or system?
• What external, restrictive factors are there?

In many cases it is the third aspect that helps to decide which method to choose from
among the 25-30 techniques available. External factors are: a. amount of time available b.
amount of resources available c. the presence and skills of experts (certain analyzing methods
cannot be realized without experts of ergonomics such as heuristic evaluation) and d. ethical

22

considerations. Our own goals influence how important it is for us to have strict control over a
given measurement, or that the measurement is reliable and valid. Often, especially in the
initial stage of a project, broader, but less resource-dependent techniques might do, as a sort
of orientation (Noyes, 2004).

What Makes a “Good” Product?
As it was described in the first part of the introduction the main goal of ergonomics is
to create the harmony between human and machine, human and work surroundings. It is an
important question how the good fitting can be measured that is what subjective, objective or
empirical methods are at stake for the researchers and practicing specialists and how to
choose the most suitable method. There is only one, but not easy question left at the end of the
chapter: what is considered to be a good product from an ergonomical aspect? Certainly for
most readers such terms as “user-friendly” or “usability” sound familiar, nevertheless
researches often have to face the fact that these terms are difficult to operacionalize, to render
measurable22. Experts of ergonomics have made strenuous efforts to define the concept of
usability.
Before the introduction of the results of these efforts let us review, along Noyes
(2004), why it is so difficult to design for people. Noyes enlists several factors:
• human adaptation
• human creativity
• human diversity and
• the difference between human expectations and actual use.

The first factor is human adaptation: most of the people can adapt rather well to bad or
inadequate design, so the existence of a problem is not always discovered. This is not a good
solution from an ergonomic point of view, as it does not realize human –centered design:
instead of fitting the machines, instruments and systems to the human, it is the human that fits
himself to them. A good example is the design of today’s keyboards: the letter allocation of
the QWERTY23 keyboard was created in the 1960s and it is still the most widespread layout to
this day despite the fact that many researchers have presented that this is not the optimal form
of the allocation of the letters (Lehto and Buck, 2008). The second factor is in close relation
with the adaptation: human creativity. People are not only good at adapting themselves to bad
22
This is especially true in the case of the term “user-friendly” (Noyes, 2004).
23
The acronym QWERTY refers to the upper line of the letters of the keyboard.

23

designs, but also at creatively enhancing the adequacy of the design. On an operating board
where the switches are impossible to tell apart for example, the operators often put different
stickers (like beer labels, magnets, etc). This is a creative solution, but it does not cover up the
omission made by designers and technicians. The variety experienced in human performance
is a challenge in the designing process: people compared to one another, and even one person
can perform very differently from time to time. This fluctuation in one person’s performance
is a real challenge for the designers. Maybe a given user during a test will perform lower with
an ergonomically better designed product than he would with a less well designed product at a
different time. Because of this during the data processing instead of the actual performance
now what is becoming generally used is the so-called reliability interval, which estimates that
based on the observed performance what performance would a given person give in 95 cases
out of 100. The fourth question has to do with human expectations: if a consumer was asked
the question, which washing machine would they choose, they would probably mention many
programs on the washing machine as an advantage. Reflecting on this, designers have created
washing machines that can operate with up to 20 programs. In reality though most of the
consumers only use two programs – a quick and a slow wash program. What consumers say
they would like to use is very often different from what they actually do.

Pheasant (2003), citing one of the pamphlets of the Ergonomic Society, defines the
ergonomically well designed product as the following:
Try to use it! Think about all the ways and circumstances in which you will want to
use it in. Does it match your body proportions, or could it fit you better? Can you see or hear
everything that you should see and hear? Is it hard to make an error during its use, or is it
easy? Is it comfortable to use it? Is it comfortable starting to use it? Could it be improved? Is
it easy to learn how to use it? Are the instructions unambiguous? Is it easy to clean it and to
maintain it? If your answer was ”yes” to all of these questions then during the process of the
design You, the user had probably been taken into consideration as well.
The text of the pamphlet highlights what criteria the product has to meet in order to
realize the harmonic fitting of human and technology. Researchers of ergonomics try to draw
up these aspects as observable criteria. These criteria are often referred to as usability as a
whole. This term is often related to the name of Professor Brian Shackel (1981) who, right
after the appearance and the widespread of personal computers, tried to operacionalize
usability. This is how the acronym, LEAF was born: the product should be easily learned
(“learnability”), be used effectively (“effectiveness”), should meet the consumer’s subjective

24

evaluation (“attitude of the user”), and should be flexible during its application (“flexibility”).
In the last decades these original criteria were completed by several others. Lehto and Buck,
in their book published in 2008, summarized the aspects of good designing as follows:
• consumption should be fast
• consumption should be accurate
• consumption should be safe, not endangering the consumer’s health
• consumption should be easy, smooth
• consumption should be easily learned
• the consumer should be satisfied during the consumption (Lehto and Buck, 2008)

The original LEAF criteria are clearly present in these criteria as well. It is important
to underline that the nature of the criteria shows that although during the process of designing
the goal is to make a product that meets the all of the consumer’s needs – so the designing
should be absolutely human-centered – this ideal state can never be reached in reality. There
are more reasons for this, here two will be presented:
• contradictions among the criteria
• beyond the ergonomic aspect other factors, like economical, engineering, practical
considerations.

Contradictions among the criteria are represented by the well-known “speed-
punctuality” trade – tradeoff – phenomenon. The time needed to reach the goal – speed – is
often an important aspect, but not in cases where other criteria are not met. In other words it
does not matter how fast we get somewhere if we are going to the wrong place. Giving more
time to carry out the task often leads to more accurate outputs (for example the error rate is
lower). A complicating factor is that the “speed-punctuality” tradeoff is not rue for everyone
in every case. Gigerenzer (2007) points out the phenomenon that in the case of experts (e.g.
professional sportsmen) more time leads to lower performance: in most cases experts, thanks
to their experiences, first think of the best solution. In this scenario more time leads to wrong
solutions (for example when a sportsman hesitates then makes the wrong decision). However,
according to Gigerenzer (2007) in the case of beginners more time leads to more accurate
solutions. Actually the criteria of speed and punctuality work against each other: the faster the
solution, the less accurate it will be. According to Lehto and Buck (2008) it is also true that in
the relation between speed and punctuality there is an optimal range: it is true that too fast

25

speed leads to inaccuracy, but it is also true that too slow speed does the same (a very good
demonstration of this is if someone tried to walk slower than normal walking speed).
Another important thing is that ergonomic companies and experts of ergonomics
constantly have to make compromises among ergonomic, economic, engineering-practical
aspects. It was Rose and co (1992) who put this into words: “in order to reach greater success
with the introduction of a new, ergonomically better method, product, it is important for the
new method, product to have economical advantages”. Lehto and Buck (2008) believe hat the
minimum expectancy is that the economical value of the method, product created along the
new project should bring back the money invested in the project.

Works Cited
Antalovits, Miklós (1998) Bevezetés az ergonómiába. In Klein Sándor (szerk)
Munkapszichológia. 2. átdolgozott kiadás, SHL Kiadó, 699-744. o.

Bertalanffy, L.V. (1950) An Outline of General System Theory. British Journal for the
Philosophy of Science, 1 (2): 134-165.

Dekker, S. (2004) To engineer is to err. In Sandom, C.,& Harvey, R.S. (eds) Human Factors
for Engineers. London: The Institution of Engineering and Technology.

Gigerenzer, G. (2007) Gut feelings: the intelligence of the unconscious. London: Penguin
Books.

Grether, W.F. (1949) The design of long-scale indicators for speed and accuracy of
quantitative reading. Journal of Applied Psychology, 33: 363-372.

Grudin, J. (2008) A moving target: the evolution of human-computer interaction. In Sears,
A.,& Jacko, J. (eds) Handbook of Human-Computer Interaction. Boca Raton, Florida: CRC
Press.

Harvey, R.S. (2004) Human factors and cost benefits. In Sandom, C.,& Harvey, R.S. (eds)
Human Factors for Engineers. London: The Institution of Engineering and Technology.

26

Hendrick, H.W. (1984) Wagging the tail with the dog: Organizational design considerations
in ergonomics. In Proceedings of the Human Factors Society 28th Annual Meeting (pp.899-
903). Santa Monica, CA: Human Factors Society.

Hendrick, H.W. (1986a) Macroergonomics: a conceptual model for integrating human factors
with organizational design. In Brown, O.,& Hendrick, H.W. (eds) Human factors in
organizational design and Management, 467-478. Amsterdam: North-Holland.

Hendrick, H.W. (1986b) Macroergonomics: A concept whose time has come. In Human
Factors Society Bulletin, 30 (2): 1-3.

Hendrick, H.W. (2002) An Overview of Macroergonomics. In Hendrick, H.W.,& Kleiner,
B.M. (eds) Macroergonomics. Theory, Methods, and Applications. New Jersey, London:
Lawrence Erlbaum Associates.

Howitt, D.,& Cramer, D. (2000) First step in research and statistics: a practical workbook
for psychology students. London: Routledge.

Kirwan, B.,& Ainsworth, L.K. (eds) (1992) A guide to task analysis. London:
Taylor&Francis.

Lehto, M.R.,& Buck, J.R. (2008) Introduction to Human Factors and Ergonomics for
Engineers. New York, London: Lawrence Erlbaum Associates.

Meshkati, N. (1986) Major human factors consideration in technology transfer to industrially
developing countries: an analysis and proposed model. In Brown, O.,& Hendrick, H.W. (eds)
Human Factors in Organizational Design and Management II. 351-363. Amsterdam: North-
Holland.

Meshkati, N. (1991) Human factors in large-scale technological system’s accidents: Three
Mile Island, Bhopan and Chernobyl. Industrial Crisis Quarterly, 5: 133-154.

Meshkati, N.,& Robertson, M.M. (1986) The effects of human factors on the success of
technology transfer projects to industrially developing countries: a review of representative

27

case studies. In Brown, O.,& Hendrick, H.W. (eds) Human Factors in Organizational
Design and Management II. 343-350. Amsterdam: North-Holland.

Munipov, V. (1990) Human engineering analysis of the Chernobyl accident. In Kumashiro,
M.,& Megaw, E.D. (eds) Toward human work: solutions and problems in occupational
health and safety, 380-386. London: Taylor&Francis.

Murrell, K.M. (1965) Ergonomics. London: Chapman and Hall.

Nayak, U.S.L. (1995) Elders-led design. Ergonomics in Design, 1: 8-13.

Norman, D.A. (1988) The psychology of everyday things. New York: Basic Books.

Noyes, J., Garland, K.,& Bruneau, D. (2004) Humans: skills, capabilities, and limitations. In
Sandom, C.,& Harvey, R.S. (eds) Human Factors for Engineers. London: The Institution of
Engineering and Technology.

Noyes, J. (2004) The human factors instrumentkit. In In Sandom, C.,& Harvey, R.S. (eds)
Human Factors for Engineers. London: The Institution of Engineering and Technology.

Oborne, D.J. (1982) Ergonomics at Work. Chichester: Wiley.

Pheasant, S. (2003) Bodyspace. Anthropometry, Ergonomics and the Design of Work.
London: Taylor&Francis, 2nd edition.

Pulat, B.M. (1992) Fundamentals of Industrial Ergonomics. Prentice-Hall, Inc.

Rose, L., Ericson, M., Glimskär, B., Nordgren,B.,& Örtengren, R. (1992) Ergo-Index. A
model to determine pause needs after fatigue and pain reactions during work. In Kumar, S.
(ed) Advances in Industrial Ergonomics and Safety 4 (Proceedings of Annual Industrial
Ergonomics and Safety Conference, 1992, Denver, Colorado, USA, June 10-14, 1992).
London: Taylor&Francis.

28

Shackel, B. (1981) The concept of usability. Proceedings of IBM Software and Information
Usability Symposium, September 15-18: 1-30. Poughkeepsie, New York: IBM Corporation.

Stanton, N.A. (2003) Product design with people in mind. In Stanton, N.A. (ed) Human
Factors in Consumer Products. New York, London: Taylor&Francis.

Stanton, N.A.,& Young, M.S. (2003) A Guide to Methodology in Ergonomics. Designing for
Human Use. New York, London: Taylor&Francis.

Taylor, F.W. (1911) Principles of scientific management. New York: Harper.

29

CHAPTER TWO: The Encounter of Human and Machine. The Human-Machine Interface
Problem on a Sensory-motoric and Cognitive Level.

Two cars – “A” and “B” – following each other are speeding. A little farther ahead the
police measures speed. Car “A” passes by the police without slowing down, car “B” reduces
its speed to the speed limit. What happened to car “A” and car “B”? It is easier to tell in the
case of car “B”: most probably they noticed the police, looked at the mileometer, then with
the help of the brake pedal corrected its speed. The driver of car “B” then reeived information
from one of the car’s – machine’s – display, then accordingly with one of the controllers – the
brake pedal – terminated the difference between the desirable and the actual conditions. After
this operation the mileometer now shows the new, altered condition: gives feedback of the
success of the operation. If feedback indicates that the operation was not successful – for
example the car is still going over the speed limit – then the cycle starts again: the consumer
reacts to the information then compares the state reached after the reaction to his original
goal.
What happened to car “A”? Here more solutions might be correct, let us examine some
of them:
• Wrong or insufficient information from the machine: the display sent the wrong
information to the driver of the car. For example the milometer always displays the
same, so the driver could not tell how fast the car goes.
• The display is not, or hardly visible: the position makes it very difficult or impossible
for the driver to read it. The average user’s choice would be to avoid the problem.
• Incorrect feedback: another possibility is that the speed changes on the milometer, but
it is not in accordance with reality. The driver stops the correction because as far as he
knows he is going with the right speed. The result is the same as in the previous two
cases: the driver cannot determine how fast to car is going.
• Malfunctioning controllers: this is a serious functional disorder. The machine sends
the correct information to the driver, the driver tries to correct, but either the
accelerator or the brake pedal does not respond. The accelerator gets stuck or the
pressing of the brake pedal does not slow the car down. The driver of the car receives
the correct information but the car does not respond to his actions.

30

• The driver ignores the information received from the machine : the display sends the
correct information, the controllers function right, but the driver of the car does not
perform correction. Ignores the received information.
• The driver of the car does not have enough background information, knowledge:
driver of car ”A” is not familiar with the speed limit, or – although this is not very
probable in this example – does not know what are the steps of the correction.
This example highlights the issues the experts of ergonomics deal with while designing the
human-machine interface. On Figure 1. the essential elements of the interface are
demonstrated: the display, the controller and the feedback, which are set in the context of the
system, the environment, the task, the machine and the user.

Figure 1.: Encounter of Human and Machine: Interface.

In the first part of the chapter the chronological evolution of the human-machine
interface problem will be discussed, from the sensory-motoric fitting to the encounter of
human and artificial intelligence.

Human-Machine Interface on the Sensory-motoric and Cognitive Level

31

It was during the Second World War that pointed out dramatically the challenges of
the designing of the human-machine interface (Grudin, 2008). Solutions far from the optimal
increased the possibility of errors, which claimed human and financial losses or lead to the
technically improved weapon-systems’ disability to reach their planned parameters (Harvey,
2004). Comparisons made by Grether (1949) indicated the negative consequences of the
ignorance of human factors in the process of designing. He observed altimeters that either
took human factors into consideration or not: instruments that took human factors into
consideration were faster and more punctual to read. Accordingly the first ergonomic
laboratories were founded in the military (e.g. MANPRINT in the U.S.A.). There are two
important issues to be considered for the researchers and practical experts: in what form
should the machine give signals and share information with the user (display), and what type
of operating board should it have (control).
The problem of the interface was altered by the widespread of computers, the
appearance of the personal computers at the beginning of the1980s. Discovery of the silicone
chip and the widespread of computers opened a new chapter in the history of ergonomics:
researches on cognitive- and software-ergonomics (Hendrick, 2002). With the help of
personal computers the common man had to face artificial intelligence more often, so
researches have shifted from the sensory-motoric level to the cognitive. How to fit the human
and the artificial intelligence? In order to solve this, the first thing to be found out is how
human information processing, thinking works: what is the human attention, memory like,
what characterizes human decision-making, what is the mental pressure a human can bear, or
what mental pressure is optimal for humans, how can machines handle and benefit from
human creativity? (Noyes and co., 2004).
It is important to underline though, that these issues – cognitive- and sensory-motoric
fitting – exist alongside one another: to this day there are many researches on how the human-
machine interface should look like in order for the human to be able to operate the machines
surrounding him effectively on a sensory-motoric level.

The Display that Takes Human Factors into Consideration:
According to Lehto and Buck (2008) what should be taken into consideration firstly
during the designing of the display – and the operators of course – is that the human-machine
relation is communication. Humans tell machines what to do and machines tell human what to
do or not to do and give feedback of the consequences of human decisions – orders that is.
This communication is very important because miscommunication is often behind accidents,

32

injuries. Communication has many characteristics, but maybe one of the most important ones
is how much information
arrives to the human from
the machine that is how
efficient the display of the
machine is in transmitting
the information24. In this
part we will take a closer
look at what should be
taken into account during
the process of designing.

These are of course general guidelines: as the display can be of many kinds, and it can
be used in many situations, the formulating of any practical advice is very difficult (see e.g.
Diaper and Schithi, 1995; Ivergard and Hunt, 2009). But general aspects and guidelines are
good when they use the information collected on human functioning, needs and nature.

Knowledge on Human Functioning, Needs and Nature
If we want to be able to examine humans, we often turn to the analogy of the
information processing system which in the case of human beings consists of inputs,
intermediate processes and outputs. Inputs are the stimuli coming from our surroundings
which we either react to or ignore. Between perception and procession on a higher level there
is cognition and attention. What happens on a higher level is often simply referred to as
“thinking”. This includes such processes as decision making, problem-solving and creativity.
All these human cognitive processes are permeated by memory, short term work-memory as
well as long-term memory. At the end of the process there usually is some motoric reaction,
action. This model helps to illustrate what types of information should be taken into
consideration when designing for humans25 (Noyes, Garland and Bruneau, 2004). The model
shows that the characteristics of perception, cognition, attention, “thinking”, memory and
motoric reactions are primarily interesting for researchers of ergonomics. In the next part
some of these aspects will be described.

24
Of course in reality it is about how effective the designer of the machine is in designing a display that takes the
consumer into consideration.
25
This is what is called “human-centered design” (Harvey, 2004).

33

A very important aspect during the process of designing the display is the
understanding of the complex nature of human attention. One important characteristic of
human attention is that it is selective: humans are able to ignore some information, while they
pay attention to others (see e.g. Broadbent, 1958). This is a criterion of normal functioning,
for if we have taken in all the information that would lead to overload, so we have to
differentiate between relevant and irrelevant information. This is not an “all or nothing” type
of processing, as some of the information that we do not consciously pay attention to is
detected too. A well-known phenomenon is the cocktail-party effect. On the one hand it
demonstrates that humans are able to pay attention to and follow one particular discussion in
the midst of many other parallel discussions – that is they are able to filter – on the other hand
if our name is mentioned in a discussion not currently followed, it attracts our attention. The
discussion rated irrelevant thus is not completely excluded (Moray, 1959). This phenomenon
though shows great individual diversity: in the original experiment of Moray (1959) 33% of
the observed people heard their names when placed in an irrelevant message, in their more
sophisticated observation Wood and Cowan (1995) found this rate to be 34.6%. As it has been
implied earlier one of the main reasons behind the selectivity of human attention is its limited
capacity: Kahneman (1973) wrote about attention as a unified, undifferentiated, limited
resource which has to be distributed in accordance to the given tasks. Multiple resources
theories (e.g. Navon and Gopher, 1979) claim that attention is not unified, but can be
differentiated in the different channels, but they agree with Kahneman int hat capacity is
limited. It further complicates the situation that some researchers (e.g. Schneider and Shiffrin,
1977) differentiate between the automatic and the conscious forms of stimulus processing,
which indicate different relations to the capacity of attention. Automatic procession is out of
the individual’s control and is independent from attention. It does not consume resources
unlike conscious procession, which is controlled and uses resources. In the course of training,
education conscious processing can become automatic (an example is the difference between
the beginner- and the experienced driver). Some aspects critical from the point of view of
both the designer and the user are evident even from this short summary, which only indicates
why it is so important to take the nature of human attention into consideration in the process
of the designing of the human-machine interface:
• The consumer needs help in deciding what stimuli is relevant and what is
irrelevant as the capacity of attention is limited so accordingly it is selective too. The
detection of irrelevant stimuli lessens the probability of the detection of the relevant

34

stimuli, while the failing of the detection of the relevant stimuli increases the risk of
errors, accidents, human and financial losses.
• The nature of attention differs greatly among the individuals. On the one hand
this concerns the capacity of attention (see e.g. Just&Carpenter, 1992; Cowan, 2001;
Halford, Wilson, &Phillips, 1998), on the other hand it also concerns phenomena like
to what extent can the individual follow the channel previously rated irrelevant
(Moray, 1959; Wood&Cowan, 1995).

• Different processes need different capacity: automatic processing does not use
up attention resources, while conscious processing does (Schneider and Shiffrin,
1977). Education and training might turn conscious processing into automatic.

• The limited capacity of attention predicts that certain aspects of the
environment and the task will lead to errors: for example if the user is asked to divide
his attention between two resource-consuming tasks (e.g. he has to read to displays at
the same time), or if alongside the relevant stimulus there are too many irrelevant
stimuli (e.g. he has to read a display but there are too many discussions going on
around him). If these situations are unavoidable, then the possibility of errors should
be reduced in the process of the designing or in worse cases at least the consequences
of the errors. In the first scenario, when the user is asked to read two displays, we can
profit from one of the sensory channels not being filled (e.g. the task is visual and the
user can be warned about a problem with a sound).

The problem of the capacity of attention goes hand in hand with the problem of how
much a human can bear. Yerkes and Dodson (1908) demonstrated that between load/activity
and performance/efficiency there is an upside-down U-shaped connection (this is the so-called
Yerkes-Dodson law). With low activity (underload) efficiency is low too. The increase of
activity leads to the improvement of efficiency to a certain point (according to the hypothesis
this is because the increase of activity has an energizing effect). After this point the increase
of activity leads to the decrease of efficiency (presumably because of such factors as stress).
The connection proposed by Yerkes and Dodson (1908) has been approved in many
researches (for example Broadhurst, 1959; Duffy, 1962; Anderson, 1988), although as for the
reasons of the connection the results are controversial (Anderson, Revelle and Lynch, 1989).

35

What is important from the point of view of designing is the optimal level of the
loading: the level where efficiency is the
highest. Interestingly enough it is the
widespread of computerization that ignores this
connection observed more than a 100 years ago
the most. Ivergard and Hunt (2009) claim that
the appearance of the computer often involves
the disappearance of the consumer’s active role
displayed in Fig. 1. Instead the computer enters
the circle of communication and operation between human and machine as shown in Fig. 4.

Figure 4: The Computer Entering in Between Consumer and Machine (Ivergard és
Hunt, 2009).

Ivergard and Hunt (2009) find this to be a problem because with the decrease of the
consumer’s active role his best abilities are taken away (such as flexibility, experience, long-
term memory, and so on), highlighting at the same time his weak points (for instance that
most humans are not very good at maintaining attention in so-called vigilance situations
where vigilance is important). In the system presented in Fig. 4. humans fill such a position
and role that his abilities do not qualify him for26. In systems using computers the
participation of humans have to be relied on which is accounted for by the negative
consequences of underload. Wood (2004) finds that the greatest problem is that most of
today’s systems require very low or absolutely no input from the operator in 95% of the time,
while if something goes wrong the claims on the operator become very high suddenly. The
goal is the minimalization of the chance of the operator falling out from the controlling cycle
either because he is daydreaming, his attention fades or he collapses under pressure. Wood
(2004) enlists a couple of possible solutions: personal factors (e.g. the decreasing of the
26
We have to note though that in reality the situation described on Fig. 4. does not exist because computers
overtaking all information-gathering and directing functions have not been invented yet.

36

possibility of sleep deprivation by redesigning ill-organized shifts), design of systems (e.g. the
introduction of secondary tasks that would increase, or have the activity stagnate, avoiding so
the monotonization of the system), design of instruments (e.g. the avoiding of hypnotizing
effects by avoiding recurring, monotone audio signals), design of environment (e.g. avoiding
the too quiet, too warm, too calm, too neutral environment), design of instruments (e.g. the
designing of an interface that requires movement, direct verbal communication and
teamwork).

Three further aspects during the process of designing:

• The human information processing system is essentially set for expectations.
Humans are less likely to respond to stimuli that they do not expect, in fact they are
more likely to hear and see what they want to hear and see.

• The operation of the memory responsible for responding to short-term stimuli
suggests that it is a good designing strategy if the information appears on the display
when it is needed (so for example not sooner, for instance during a former phase of the
process).

• It is an important aspect for most humans how much effort do they have to
make in order to get the given information: what first appears to be a demanding task
many people will avoid. This is especially true if there are more stimuli around trying
to claim the human’s attention. So the designer has to design an interface where the
information is quickly and easily accessed.

In accordance with this and other basic information on humans, some principles can
be identified in connection with the designing of displays. It is essential that the information
on the display is relevant, easily accessible, easily discriminated. It is important that the
criteria, function, danger or ill-use of the task have valid indicators. Before describing the
principles of designing in detail the boarder line between design and ergonomics has to be
made clear: Norman (1988) differentiates between artistic value and ergonomic usability.

One more subject has to be dealt with shortly: the types of displays. Displays are
normally visual or audio (or the combinations of the two). Displays relying on other

37

modalities are rare (e.g. the sense of smell or touch). Visual displays can be static which
means that their content does not change: for example signals, labels, road signs, books. The
other type is the dynamic display which represents variable information: such as the
milometer, fuel indicator, oil pressure indicator or the display indicating the temperature of
the cooling water. Dynamic displays can be analogue or digital depending on in what form
they show the information. In most cars for instance dilatometers are analogue though there
are some digital ones too. Displays can be grouped along their function too: 1. status displays:
such as the milometer, which represents a current state 2. warning displays: these indicate
unusual states, danger, such as the different sirens 3. predictive displays: these make
predictions based on data and trends of the system, for example the system that based on the
car’s average fuel-consumption and the currently available fuel predicts for how many more
kilometers will the fuel be sufficient for 4 instruction, recommendation, order displays. An
important question is how the display encodes the information? There are several options:
spatial (for example diagrams, charts, figures, which represent elements connecting through
space and time); symbolic (for example letters, numbers, or other non-verbal symbols); and
imagery (for example the use of the image of fire, flame on a sign indicating danger).

The Principles of Designing

In the following section two overlapping principle-systems will be discussed. The first
one is by Lehto and Buck (2008) consisting of 27 elements, and the other is by Macredie and
Coughlan (2004) consisting of 7 elements.

Lehto and Buck (2008): The 27 Principles of Designing

These 27 principles can be drawn up by 4 wider topics (Figure 5.):

38

Figure 5: The 4 main topic in display design by Lehto and Buck (2008)

First Topic: The Selection of the Sensory Modality
First the designer has to decide which sensory modality is most in accordance with the
application in question. The first designing principle is related to this:
• First Principle: the planned function of the display – what it wants to show –,
what are the sensory requirements of the background tasks, of what nature are the
perception and detection of the future consumer (the senses of seeing and hearing of
elderly people are usually worse than that of younger generations) are the factors that
determine which sensory modality is the best. This is obviously a complex topic, so
we are forced to focus on a few, general realizations: if we want to put a big amount of
information on the display, then we do not really have a choice – the display will have
to be visual. Some other modality can also be part of the display, but visuality is an
obligatory element. When the designer intends to place little information on the
display, then the choice among the sensory modalities is not so evident anymore.
Audio signals for example are good for drawing attention to change, to unusual, urgent
situations. It is not by any chance that these are mostly used as alarm signals. When
choosing the modality it is very important to take other factors of the situation, the
system into consideration: for example under how much visual pressure does the

39

consumer have to function? If it is a lot then the application of another modality (e.g.
the sense of hearing, seeing or smelling) in the display is advisable. A good example is
the use of tactile signals (e.g. the vibration of mobile phones), in situations that claim
both the visual and the audio channels. Of course all modalities have their advantages
and disadvantages: the use of audio channels in noisy environments for example is not
very favourable, and loud signals in themselves can puzzle the consumer (a good
example is the already described case where the operators of the Three Mile Island
nuclear power plant distracted by the too loud, warning sirens, leading to and even
greater disaster).
• Second Principle: displays combining sensory modalities are especially
effective. An example would be the kind of computer screen that gives an audio signal
when an important message arrives (this way combining the visual display and the
audio signal). This is especially useful when the user has to follow more than one
display at a time. This way, if he receives an audio signal when a critical value appears
on one of the displays, then it is more likely that he will be able to respond in time to
the current situation.

Second Topic: The Positioning and Arranging of the Display
The second large topic in the designing of the display is the positioning and arranging
of the display.
• Third Principle: visual displays have to be placed where they are visible, and the more
important information has to be placed into a center position. Displays not detectable
for humans are not detected. Important information has to be placed in the center, so
that they can be seen more easily, more often, more accurately. During designing
possible obstacles have to be taken into consideration such as plants or other signs in
the displays’ surroundings. Visual overload is the problem of big cities: too many
lights, neon can confuse the consumer (for instance the driving person trying to read
the road signs).
• Fourth Principle: the display has to show the information when it is needed. This is
because of work memory restrictions: if the information is introduced at the right time
(and no sooner or later), then it does not have to be remembered and cannot be
forgotten. This reduces the chance of making an error a great deal.

40

• Fifth Principle: if there is more than one display then the displays, if there is only one
display then the elements of the display have to be arranged according to the sequence,
steps of the process. The usefulness of this is easy to see: the sequent arrangement and
the not sequent arrangement differ significantly in how much eye movement is
required in the performing of the task. If the arrangement is consistent with the
sequence then the time spent on searching is reduced, so more time can be spent on
working on other parts of the task.
• Sixth Principle: in the case of tasks which require the integration of the information
the integration has to be presented on the level of the display as well. Elements of the
display have to be arranged so that the connections and differences of the elements are
easily perceived. Colour-coding is a common strategy, but there are other options too.
For example if the related indicators are designed so that they point in the same
direction in case of normal functioning, then the different position of an indicator will
instantly gives a warning that something is wrong. This way the problem is recognized
without the consumer’s close examination.
• Seventh Principle: indicators of the displays that are near to one another will probably
be perceived as cohesive elements. This is the principle of proximity. If the proximity
is actual functional proximity as well, then it can be made even more obvious by
placing the cohesive elements into a frame (for example by a light-grey metal frame).
• Eighth Principle: the good designer positions the display and the elements of the
display so that they have a clear spatial reference.

Third Topic: The Visibility of the Display’s Elements
Visibility is one of the most emphasized criteria in the designing of displays. The size
of the displays is obviously important from this point of view, though the recommended size
depends on many different factors (for instance from how far the display needs to be
perceived, how much lighting is there, etc).
• Ninth and Tenth Principle: individual differences and circumstances should be taken
into account during the process of designing. For example characters and symbols
should be larger and bold when visual conditions are poor or readability is important.
• Eleventh Principle: the contrast between visual elements and their background should
be adequate on a display. For instance in case of printed material the brightness
contrast between characters and their background has to be at least 50%. In most cases

41

this is not an issue as the contrast is mostly 80% or more. In case of CRT or LED
screens though contrast is a challenge for designers: here the problem is that there is a
glass layer between the visual elements and their background. With these displays the
contrast has to be at least 88% and the higher this rate is the better. In case of larger
screens the minimum is 94%.
• Twelfth Principle: avoid over-crowdedness when designing a display! Over-
crowdedness is the consequence of the designer trying to position too much
information on the display. This over-packing involves the miniaturizing of the
elements too. The problem is that both the over-crowdedness and the application of
smaller characters lead to decreases the visibility of the contents of the display. There
are several options how to solve this problem: 1. reducing the number of the visual
elements 2. replacing the text with pictures or symbols 3. increasing the size of the
display.
• Thirteenth Principle: when designing for the visibility aspect, groups with special
needs such as elderly people and unfavourable environmental conditions should be
taken into consideration too. Lehto (1992) stresses the importance of the testing of the
display for the predictable unfavourable conditions such as dirt, smoke, fog, steam,
etc. It was discovered during such researches that the visibility of symbols is less
affected by dirt and other contaminants. It is for this reason for instance that most road
signs contain symbols.

Fourth Topic: The Content of the Information and Its Encoding Method
The most important job of the display is to tell the user what he should know, but has
not known yet. The method of encoding the information is important too. Some encoding
methods are better for correct understanding. But first let us take a look at the principles about
the types of information.
• Fourteenth Principle: instructions on the display should be affirmative as we respond
slower to negative instructions. It is better to say “Do this” than saying “Don’t do
this”.
• Fifteenth Principle: already the designer has to be selective when picking the
information. What should be on the display and what should not? This is important
because if there is too much information on the display that triggers avoidance in the
consumer. They simply will not read, they will ignore the message.

42

Ergonomics - edited study book -

Ergonomics - edited study book -

Recommended

Recommended

More Related Content

What's hot

What's hot (18)

Viewers also liked

Viewers also liked (16)

Similar to Ergonomics - edited study book -

Similar to Ergonomics - edited study book - (20)

More from Balazs Pankasz

More from Balazs Pankasz (20)

Recently uploaded

Recently uploaded (20)

Ergonomics - edited study book -