Engineering aesthetics and aesthetic ergonomics: Theoretical ...

ERGONOMICS, 2003, VOL. 46, NOS 13/14, 1273 – 1292
Engineering aesthetics and aesthetic ergonomics: Theoretical
foundations and a dual-process research methodology
YILI LIU*
Department of Industrial and Operations Engineering, University of Michigan,
Ann Arbor, MI, 48109-2117, USA
Keywords: Engineering aesthetics; Aesthetic ergonomics; Aesthetic human
factors; Dual-process research methodology.
Although industrial and product designers are keenly aware of the importance of
design aesthetics, they make aesthetic design decisions largely on the basis of their
intuitive judgments and ‘educated guesses’. Whilst ergonomics and human factors
researchers have made great contributions to the safety, productivity, ease-of-use,
and comfort of human-machine-environment systems, aesthetics is largely
ignored as a topic of systematic scientific research in human factors and
ergonomics. This article discusses the need for incorporating the aesthetics
dimension in ergonomics and proposes the establishment of a new scientific and
engineering discipline that we can call ‘engineering aesthetics’. This discipline
addresses two major questions: How do we use engineering and scientific methods
to study aesthetics concepts in general and design aesthetics in particular? How do
we incorporate engineering and scientific methods in the aesthetic design and
evaluation process? This article identifies two special features that distinguish
aesthetic appraisal of products and system designs from aesthetic appreciation of
art, and lays out a theoretical foundation as well as a dual-process research
methodology for ‘engineering aesthetics’. Sample applications of this methodol-
ogy are also described.
1.
Introduction
While aesthetics and appearance have always played a role in product and system
design, this role will dramatically increase in the 21st century as the society and
market become more sophisticated and the manufacturing technologies become
further developed. To compete and succeed in the market place, manufacturers will
have to look beyond reliability and physical quality, and pay more and more
attention to the aesthetics and subjective quality of their products. In the more
established technology sectors, product reliability is a ‘given’ to the customers and is
often regarded as a basic qualifying ‘ticket’ to enter the market place. Other features
and metrics, such as usability and aesthetics often separate the winners and losers.
Although industrial and product designers are keenly aware of the importance of
design aesthetics, they rely largely on their ‘educated guesses,’ ‘talents’, or ‘gut-
feelings’ in making design decisions (Noblet 1993). Some of them also consult trend
analyser’s ‘hunches’ and predictions. There is an obvious lack of systematic,
scientific, and engineering methods to help them make aesthetic design decisions and
*e-mail: yililiu@umich.edu
Ergonomics ISSN 0014-0139 print/ISSN 1366-5847 online # 2003 Taylor & Francis Ltd
http://www.tandf.co.uk/journals
DOI: 10.1080/00140130310001610829

---

1274
Y. Liu
conduct aesthetic evaluations. There is also an obvious lack of a scientific and
theoretical foundation or framework to organize, communicate, and explain related
ideas and concepts.
As a scientific discipline that devotes itself to the study of human – machine –
environment systems, human factors and ergonomics has long established its goals
of enhancing the safety, comfort, productivity, and ease-of-use of products and
systems (Wickens et al. 1998) and has made great strides toward achieving these
goals. Although there have been calls for the expansion of the research scope of
human factors to include emotional aspects of design and there have been some
endeavours toward that direction (Nagamachi 1995, Jordan 1998), aesthetics has not
generally been regarded as one of the central topics of human factors research.
In a closely related discipline, ‘consumer behaviour’ has long been one of the
central topics of marketing research, where design and product aesthetics are
examined from the perspective of how they may influence people’s purchasing
decisions and their preferences or behaviour as buyers and consumers of market
products (Sewall 1978, Holbrook and Huber 1979). Results of marketing research
are extremely useful for product design, advertising, and marketing, but there are
major limitations in its current scope of research: Because of its main focus on
‘marketing’, it does not offer a comprehensive view of the design of human –
machine – environment systems, many of which are not designed for ‘marketing’ or
‘consumption’ (Liu 2000a). Examples of these systems abound and include hospitals,
schools, and military and public service systems.
This article argues that it is time that we add aesthetics as an important dimension
to human factors research. Furthermore, because design decisions may have ethical
implications, it is also important to incorporate the ethics dimension explicitly and
systematically in human factors research and practice. This argument can be further
supported by a brief examination of three fundamental human pursuits.
As shown in Figure 1, ancient philosophers believed that all human pursuits can
be classified into three fundamental categories: pursuit of truth, pursuit of beauty,
and pursuit of the good and right. Corresponding to this trinity of fundamental
pursuits there appears to be three types of judgments: the cognitive (or scientific), the
aesthetic, and the moral, which are the topics of study in three main branches of
philosophy: metaphysics, aesthetics, and ethics. Metaphysics addresses the issue of
truth – the true and fundamental nature of the universe and existence (what truly
exist). Aesthetics addresses the issue of beauty and related notions (e.g., tragedy,
sublimity). Ethics addresses the issue of what is a good (or bad) thing and what is a
right (or wrong) action. As some philosophers put it, ‘Truth, beauty, and the good
may be the traditional staples of philosophy (Honderich 1995: 14)’.
The foundation for traditional human factors is mainly that of metaphysics and
the pursuit of truth, and traditional human factors issues can be organized along
three dimensions: the arousing quality dimension, the dimension of information
processing demands, and the dimension of psychosomatic soundness. A broader
view of ergonomics should be based on all three pursuits, and should include an
aesthetics dimension and an ethics dimension. We may use the term ‘aesthetic
ergonomics’ or ‘aesthetic human factors’ to describe an ergonomic approach that
systematically incorporates all the five dimensions (the aesthetics and the ethics
dimensions, together with the three traditional dimensions). These five dimensions
together offer a structured and comprehensive view of the diverse range of human –
machine – environment systems and products, can help identify ignored important

---

Engineering aesthetics and aesthetic ergonomics
1275
Metaphysics
Ethics
(Natural Sciences)
(Social Sciences)
Truth
the Good
Beauty
Aesthetics
(Arts)
Figure 1.
The three fundamental human pursuits are shown in three circles. The three
corresponding branches of philosophy are shown in italics, and the three corresponding
fields of modern disciplines are shown in parenthesis. The foundation for traditional
human factors is mainly the upper-left circle, while aesthetic ergonomics should be based
on a comprehensive view of all the three circles (from Liu 2000a,c).
research areas, explain the demise of old work systems and products, and predict the
possible emergence of new work systems and products. For example, these five
dimensions help us realize that aesthetic ergonomics is not just about tangible
products made to sell or consume; it is also about intangible systems, jobs, and
environments. Aesthetic ergonomics is not just about design for pleasure; it is about
displeasing situations as well.
As an illustration, the aesthetic dimension is shown in Figure 2 with the dimension
of ‘psychosomatic soundness’. Future workplace and products should not only be
safe, but rejuvenating, as shown in Quadrant 1 (top-right quadrant) of Figure 2.
Some products and activities can have negative psychosomatic consequences,
although they may be pleasurable, as shown in Quadrant 4 (bottom-right quadrant),
such as reckless thrills and additive behaviours. Similarly, not all healthful situations
are pleasing or attractive to the experiencing person – Physical rehab or drug
rehabilitation programs can be extremely painful but healthful to the patient during

---

1276
Y. Liu
Rejuvenating
Some curative / remedial/
Healthful
Refreshing
corrective measures
Invigorating
Rehabilitation
^
^
safe
unattractive
comfort >>
attractive
displeasing
pleasing
Stressful
Adventurous
Dangerous
Riskyor reckless thrills
Hazardous
Harmful
Addictive behavior
Life/threatening
Figure 2.
The two-dimensional space defined by the aesthetics dimension and the dimension
of psychosomatic soundness. Other two dimensional spaces for job/product/system
classification can be found in Liu (2000a).
the treatment process, as shown in Quadrant 2 (top-left quadrant). Quadrant 3
(bottom-left quadrant) shows displeasing and harmful situations that can be called
stressful or even dangerous. But when the aesthetics and the ethics dimensions are
examined together, certain dangerous/displeasing situations have high ethical values
such as the jobs of prison guards, policemen, and firefighters. We often use words
like ‘brave’ and ‘heroic’ to describe them (Liu 2000a; 2003).
In this article, I focus on the aesthetics dimension and emphasize the need to
establish a research discipline that devotes itself to the systematic study of aesthetics
in human-machine-systems, and we may call this discipline ‘engineering aesthetics’. I
discuss the theoretical foundations for this discipline and propose a comprehensive
and rigorous dual-process research methodology for ‘engineering aesthetics’.
2.
Engineering aesthetics
The scientific discipline ‘engineering aesthetics’ should address two major questions:
(1) how can we use engineering and scientific methods to study aesthetic concepts in

---

Engineering aesthetics and aesthetic ergonomics
1277
system and product design? (2) How do we incorporate engineering and scientific
methods in the aesthetic design and evaluation process (beyond designer’s intuitions
and trend analyser’s ‘hunches’)?
As discussed later in this article, philosophers and art critics have been debating
about the nature of beauty and other aesthetic concepts for a long time. Although
these debates may offer important insights into aesthetic questions and provide
useful perspectives from which we can examine aesthetic concepts, these debates are
not, and they were not meant to be, scientific studies. Similarly, industrial designers
in various fields of design have developed a large base of design heuristics, success
stories, and winning strategies. They are extremely valuable ‘food for thoughts’.
They may serve as a rich soil for the growth of the discipline of ‘engineering
aesthetics,’ and will in return benefit from the fruits of the discipline. However,
designers’ heuristics are not, and they were not meant to be, scientific and
engineering statements or findings.
In daily life, the word ‘aesthetics’ is used widely in diverse contexts ranging from
cosmetics and beauty salons to the appreciation of enjoyable objects and fine arts.
However, currently in academic settings and scholarly discourse, the use of the term
‘aesthetics’ is primarily centered around the theory of art and the criticism of the arts
(Honderich 1995). Encouragingly, a number of empirical studies of aesthetic
concepts have appeared that can be found both inside and outside of the domain of
arts (e.g., Langlois and Roggman 1990, Hekkert and van Wieringen 1996). Both the
philosophical discussions and the empirical studies agree that aesthetic responses and
appraisals are not limited to beauty judgments. Rather, there is a whole range of
aesthetic notions such as the sublime, the beautiful, the pretty, the humorous, the
comic, the ‘cool’, the fashionable, the funky, the ugly, and the tragic (Honderich
1995, Devereaux 1997). Further, aesthetic experiences and responses are multi-
dimensional in the sense that overall aesthetic response is the joint outcome of a
multitude of factors. The issues of debate among philosophers, art critics, and
designers are what these factors are and how they contribute to aesthetic response,
either positively or negatively. The goal of engineering aesthetics is to employ
scientific, engineering, and mathematical methods to systematically identify and
quantify the roles of aesthetic factors in system design.
In addition to the multidimensional nature of aesthetic experience, I would like to
point out that aesthetic appraisals of products and work systems possess two special
features: First, they tend to be multi-modal; and second, they tend to be interactive.
These two features distinguish aesthetic appraisal of products and work systems
from aesthetic appreciation of arts, and pose special and fascinating challenges to
engineering aesthetics. Let me discuss the two features below.
First, aesthetic appraisal of product and system design tends to be multi-modal in
the sense that more than one sensory modality is likely to be involved in the process.
While fine art appreciation is primarily visual, aesthetic appreciation of a product or
work system may involve the interplay between a person’s visual, auditory,
olfactory, tactile, haptic, and even proprioceptive systems. For example, the visual
appearance and the surface texture of a perfume bottle are often as important as the
perfume itself in a consumer’s aesthetic evaluation of the perfume. Similarly, when
making aesthetic appraisals of a potato chip, consumers examine with their eyes and
feel with their fingers the shape, the contour, and the thickness of the chip. They
smell with their nose and taste with their tongue the flavour of the chip, feel with
their teeth and jaw the biting pressure, and hear with their ears the cracking sound of

---

1278
Y. Liu
breaking the chip. A winning brand will have to please the consumer along all the
modalities.
Second, aesthetic appraisal of a product or system may be not only multi-
dimensional and multi-modal, but interactive as well. In other words, the consumer
as an appraiser may not be a passive examiner of the appraised object. The appraiser
may actively interact with the object, test its reactions, and communicate with the
appraised, which may or may not ‘communicate back’. For example, before
purchasing a new car, we not only look and feel the car in a parking lot, but always
test drive it to see how it responses in various driving situations and whether it offers
us the ‘driving excitement’. In a classroom or lecture hall, students and audience
consider a speaker ‘engaging’ if the speaker is not merely an object to look at and
listen to, but a live person with whom they can interact in interesting ways.
Clearly, engineering aesthetics must develop theories and research methods to
address all the three characteristics. In Figure 3, I propose a framework for
representing the multi-dimensional, multi-modal, and interactive nature of aesthetic
appraisal of art work, products and work systems. As illustrated in Figure 3, the
overall aesthetic evaluation as a psychological response (CAE) is an integration of
responses along various specific psychological dimensions, Cj, j = 1, . . ., m, each of
which is based on several physical or environmental dimensions, Fi, i = 1, . . ., n.
Further, aesthetic evaluation is not a passive process. Individual characteristics of
Environment/Object
Individual
(causal modeling)
Φ
Ψ
Φ1
Ψ1
Φ2
Ψ2
(psychophysical methods)
*
*
ΨAE
Φi
Ψj
*
*
Φn
Ψm
(Content analysis/
(unidimensional scaling/
(conjoint analysis)
interaction analysis) multidimensional scaling/
factor analysis/
cluster analysis)
Figure 3.
A model of the multidimensional, multi-modal, and interactive characteristics of
aesthetic evaluation of products, systems, and environments. Selected major research
methods for each component of the model are shown in parenthesis correspondingly.

---

Engineering aesthetics and aesthetic ergonomics
1279
the perceiver, such as income level, age, gender, cultural background may influence
how the perceiver selects and responds to the information from the environment/
object, as shown by the arrows at the top of Figure 3, pointing from the individual to
the environment/object and to the mapping processes between the F’s and the C’s.
Figure 3 is not only a conceptual model of the processes involved in aesthetic
evaluation; it also shows the various mathematical/statistical/experimental
methods that can be used to examine these processes. For example, as discussed
later in this article, content analysis and interaction analysis can be used to
identify a list of the physical/environmental/task dimensions, Fi’s, that may be
relevant. Unidimensional scaling, multidimensional scaling methods, as well as
methods such as factor analysis and cluster analysis can be used further to
examine the relative importance of and the structural relationship among each of
these dimensions in affecting the various psychological dimensions, Cj’s. In other
words, how do the Fi’s map onto the Cj’s? Conjoint analysis can be used to
answer the following questions: How do the Cj’s combine to form the overall
impression of CAE? What are the relative importance of each dimension in
forming the overall impression of CAE? The hypothesized causal flows or
relations in the model can be examined with causal modelling methods.
Psychophysical and psychological experiments can be used to study the absolute
and relative thresholds of the perceivers in aesthetic judgments and to establish
related psychophysical magnitude functions. Later in this article I propose a dual-
process research methodology and describe in detail the use of these methods for
engineering aesthetics research. But first, let me briefly discuss the theoretical
foundations for engineering aesthetics.
3.
Theoretical foundations
3.1. Philosophical theories
Although most philosophers agree that not all aesthetic judgments are about art, the
philosophy of aesthetics is largely a philosophy of art. Discussions of aesthetic issues
of art and beauty can be traced back to ancient Greek philosophy, but Kant’s
Critique of Judgment (Kant 1790/1952) was generally regarded as the foundational
work that established aesthetics as a distinct discipline within philosophy. The topics
discussed by Kant such as the analysis of the beautiful and the sublime, the logic of
aesthetic judgments, and the moral function of the aesthetic are still among the
central issues of aesthetics today.
Philosophers in the school of aestheticism believe that aesthetic judgment or
aesthetic attitude is a distinct judgment that exists ‘for its own sake’, and is
independent of any utilitarian, instrumental, cognitive, emotional, or moral
judgments (Kant 1790/1952). But other philosophers such as instrumentalists believe
that aesthetic objects are judged to possess aesthetic value because they are a means
or instruments to some ends. They question whether we can and whether we should
have a purely aesthetic judgment (Schiller 1795/1967).
Some philosophers adopt an analytic view of aesthetics and attempt to identify the
invariant elemental ingredients and compositional structure of aesthetic judgments,
while some others examine aesthetics from a historical or sociological perspective to
investigate the historical, social, and cultural factors that influence taste and
aesthetic value. Some philosophers believe that aesthetics must engage itself with the
philosophy of mind and metaphysics in order to achieve a deeper understanding of
the relationship between the aesthetic value of an artwork, the mind of the artist, and

---

1280
Y. Liu
the notions of intention, belief, and emotion. Some philosophers seek and embrace
‘an ethical turn’ of aesthetics and make strong arguments about the moral function
of art, the moral responsibilities of the artist, and the moral limits of aesthetic
appreciation (Ross 1994, Honderich 1995, Cooper 1997, Korsmeyer 1998).
3.2. Psychophysical theories (also called formal or compositional theories)
While most psychologists date the birth of psychology as a scientific discipline in
1879, the year when Wilhelm Wundt established the first experimental psychology
laboratory at the University of Leipzig, no one argues that the forerunner of
experimental psychology was Fechner and his work in psychophysics. In fact, some
psychologists choose to celebrate 1860, the year of publication of Fechner’s Elements
of Psychophysics, as the birth of psychology from the intellectual incubator of
philosophy (Fechner 1860).
Fechner developed experimental techniques and measuring methods for investi-
gating the quantitative relationships between psychological responses and physical
stimuli. Along with his research on sensory thresholds, psychometric functions, and
psychophysical laws, he pioneered the experimental study of aesthetics (Fechner
1876). His research approach is characterized by systematic manipulations of the
dimensions of simple visual stimuli such as rectangles and ellipses with the research
goal of discovering relationships between aesthetic response and the manipulated
dimensions. Another goal of this research approach is to understand aesthetic
responses to more complex objects such as real artwork through ‘synthesizing’
research findings with more primitive pictorial elements. The research focus is mainly
on identifying the basic pictorial features and compositional patterns that please or
displease the senses. This ‘bottom-up’ approach continues in the branch of modern
experimental aesthetics that focuses on analysing essential aesthetic features of
stimuli such as shape, colour, complexity, order, rhythm, novelty, and prototypi-
cality that may affect an individual’s aesthetic response (Farnsworth 1932, Birkhoff
1933, Eysenck 1941, Austin and Sleight 1951, Granger 1955, Schiffman 1966, Boselie
and Leeuwenberg 1985, Martindale and Moore 1988).
A major criticism of this ‘bottom-up’ approach is that aesthetic response to
complex aesthetic objects such as an artwork is not simply the ‘sum’ of the aesthetic
responses to its components. The ‘top-down’ approach attempts to understand
aesthetic response as a whole. Real works of art or photographic images of nature
are often employed as stimuli (Berlyne 1971, 1974, 1975, O’Hare and Gordon 1977).
However, this approach encounters a major criticism that its lack of systematic
control of the stimulus variables and dimensions renders its findings difficult to
interpret. A more recent approach attempts to deal with both criticisms by
employing stimuli that are based on systematic manipulations of realistic images
along well-defined dimensions (Boselie 1992, Nodine et al. 1993, Hekkert and van
Wieringen 1996).
3.3. Cognitive (symbolic or association) and social theories
Many researchers in aesthetics and psychology believe that human aesthetic
responses are influenced not only by the form or the apparent surface attributes,
but also by the content or the symbolic meaning of the stimuli. Different individuals
may have different aesthetic responses to the same object or stimuli because they
carry different symbolic or connotative meanings to the individuals and evoke
different memories or mental associations.

---

Engineering aesthetics and aesthetic ergonomics
1281
Research methods and results from cognitive psychology, sociology, and
anthropology are borrowed to study the role of symbolic meaning, the stimulus
features that carry symbolic meaning, and the acquisition of symbolic meaning for
different individuals. Research methods and results from social and personality
psychology are also employed to examine the role of personality, race, gender, and
cultural backgrounds in aesthetic response (Adams and Crossman 1978, Jackson
1992, Franzoi and Herzog 1987, Cunningham et al. 1995).
3.4. Ecological theories
According to the ecological approach to perception pioneered by Gibson (1977),
there exists a direct relationship between animals and environment, and the animals
(including humans) pick up relevant information in the ambient array directly. The
ambient array refers to the ambient light with some sort of structure or arrangement,
such as a pattern, a texture, or a configuration. The information in the ambient array
is always relational in the sense that it always specifies the dimensions of the
environment on the scale of the perceiver and the habitat it occupies. The
information available to the perceiver is always veridical and complete in specifying
the environment.
The central concept of ecological psychology is the concept of affordances
introduced by Gibson, who states, ‘The affordance of anything is a specific
combination of its substance and its surfaces taken with reference to an animal’
(Gibson 1977: 67). The affordance of anything is what it ‘offers the animal, what it
provides or furnishes, either for good or ill’ (Gibson 1979: 127).
The ecological approach to perception and the concept of affordances have been
employed mainly in studies of motion perception, environmental support for action,
and ‘usability’ of objects. For example, in motion perception, according to Gibson,
information for motion perception is contained in the ambient optic array that
surrounds the perceiver. The flow patterns of the optic array, called optic flows,
provide information for persisting or invariant structures of the environmental
layout; they also provide information for the location and action of the perceiver
with respect to the environment he moves in (Gibson 1977). In action, experimental
evidence showed that individuals make judgments of ‘usability’ of objects according
to their own action capabilities. They made judgments about whether a staircase
affords climbing according to a constant proportion of their leg length with respect
to the riser height and tread depth. Similarly, they judged the ‘sittability’ of chairs
and the ‘passability’ of walkways with body-scaled information (Turvey et al. 1978,
Michaels and Carello 1981).
It is not clear how the concept of affordances can be fruitfully employed in the
study of aesthetics. A chair’s affordance may provide information to an individual
about whether and how it affords or supports sitting. It is not clear how this
affordance can please or displease the senses and elicit the aesthetic responses from
the sitter. Is the concept of ‘affordances’ alone sufficient to explain aesthetic
responses? Do we need concepts such as ‘aesthetances, pleasantances, or excitances’?
These questions need to be addressed in aesthetics research for those who adopt the
ecological approach.
3.5. Natural and sexual selection theories
Natural selection theories of aesthetic response essentially adopt a Darwinian
approach to aesthetic theorizing, in that aesthetic responses are explained in terms of

---

1282
Y. Liu
evolutionary adaptation and survival. For example, Appleton (1975) suggests that
the kind of landscapes that are most pleasing to humans once would have provided
us a ‘refuge’ from potential danger or a ‘prospect’ for exploration of surrounding
environments (Appleton 1975). Langlois and Roggman (1990) suggests that cross-
cultural preferences for attractive faces may be explained by evolutionary processes
that favor symmetrical, average, and prototypical facial features (Langlois and
Roggman 1990).
It has been suggested that symmetric faces may reveal a higher level of ability to
resist parasites. Many adult male facial and body features that are now regarded
as attractive once would also have supported him to be a stronger hunter. Many
adult female facial and body features that are considered attractive may also reveal
higher fertility levels that are critical for reproductive success (Buss and Barnes
1986).
While natural selection theories focus on the survival of the species or the
individual, sexual selection theories explain aesthetic response from the
perspective of sexual desire and mating opportunity. Many exhibitional or
decorative features of animals enhance their mating opportunities (such as the
beautiful plumage of birds and the musky odours of some animals in the mating
season), although these features are not necessarily beneficial and may be harmful
to individual survival (such as the peacock’s tail and some deers’ large antlers)
(Buss 1985).
4.
A dual-process research and evaluation methodology
As illustrated in Figure 3, aesthetic appraisal or evaluation of products and systems
is multidimensional, multimodal, and interactive. The theories and research
approaches described above either focus on one aspect or dimension of aesthetic
response or are qualitative in nature. To achieve a comprehensive, rigorous, and
quantitative understanding of aesthetic responses in a design context, we need to ask
two sets of questions. The first set is ‘top-down’: what is the conceptual and
mathematical structure of the aesthetic constructs in question? What are the major
psychological and physical dimensions involved? How do we measure and scale these
dimensions (ordinal, interval, or ratio scale)? How are the dimensions related to each
other and what is the relative importance of each dimension? What type of
multidimensional evaluation scale can be developed to measure the aesthetic
construct with adequate validity and reliability?
The second set of questions is ‘bottom-up’: how sensitive are the perceivers in
detecting small variations in aesthetic variables? What are their absolute and relative
thresholds in detection? What are their abilities to perceive and judge values,
changes, and variations in design parameters? What are their preferences of the levels
of values of aesthetic variables?
The two sets of questions can be addressed by two types of research methods, as
shown in the dual-process engineering aesthetics research methodology proposed by
Liu (2000b). This dual-process methodology consists of two parallel but closely
related lines of research (Figure 4). The first process (shown on the left side of Figure
4) is called ‘multidimensional construct analysis or multivariate psychometric
analysis’, whose goal is to establish a ‘global’, ‘top-down’, and quantitative view of
the critical dimensions involved in a specific aesthetic response process. The second
process (shown on the right side of Figure 4) is called ‘psychophysical analysis’,
whose objective is to establish a ‘local’, ‘bottom-up’, and quantitative view of the

---