Externalisation and Design
, Layda Gongora
Lancaster, LA1 4AW, UK
43 Temple Row
Birmingham, B2 5LS, UK
External representations are ubiquitous in design from
blue-foam models, to formal requirements documents.
This paper seeks to explicate the role of externalisation in
the light of literature in philosophy, psychology, and design
practice. The apparent conflict between theories of
embodiment, which emphasises tacit action, and the ideal
of reflective practice is resolved in a rich interplay between
tacit and explicit knowledge and reasoning. By
understanding the kinds of external representation in design
their properties, and functions, we are able to make sense of
tools and techniques for reflection and creativity and we
hope ultimately improve them and design itself.
design, embodiment, reflective practice, external
INTRODUCTION AND MOTIVATION
In this paper we seek to unpack different forms of
externalisation and in particular the role it plays in design.
Ethnographies often emphasise shared representations as
enablers of collaboration. External representations are also
central to distributed cognition, where they act to augment
of processing or memory, and in philosophical theories of
embodiment. Furthermore, we all make use of notes and
calendars, wall-planners and blogs; and even this paper acts
as a critical externalisation of the authors' own thinking.
Externalisation is ubiquitous and important to understand
as it is often a critical part of the domains we study in
designing for interaction. However, it is also central in the
process of design itself, as evidenced by blue-foam models,
architectural plans and UML diagrams; and furthermore to
our own intellectual processes as researchers.
What is externalisation?
We all interact with external environments and artefacts as
part of our day-to-day lives, as emphasised in various
approaches including ecological perception  and
situated action . Often these are given by the world:
waiting for a kettle to boil, digging the earth, or the
movements and activities of those studied in field studies.
We are not isolated; being human means interacting with
the impingements and resistances of the outside world from
stones to people to computers.
Of course, we do not simply react to the external world but
actively shape it to serve our needs: building walls and
roofs for shelter, weapons for hunting and war, cars to
drive, and fields to feed.
Externalisation is the step beyond, the active shaping of the
world as an intellectual resource, maybe a uniquely human
ability and certainly the foundation of culture and
civilisation. Externalisation involves the embodiment,
representation and exploration of our own thoughts,
feelings and interior life. As we shall discuss further, this
takes many forms and serves many overlapping purposes
from communication to elaboration of our nascent ideas.
The term externalisation itself reflects a philosophical and
practical tension: it suggests both embodied interactions
with external artefacts, but also the process of making
internal representations external. In art and design this
reflects dual views of creativity as internal muse or
This paper builds on previous analysis of the practical use
of externalisation , and on literature on embodiment
and reflection, notably Schön's studies of different forms of
reflection , which is often facilitated by external
representations. We will illustrate an unfolding framework
of dimensions and categories using examples from our own
past studies, published data of others and reflective
anecdotes, which we hope will be familiar in the readers'
We also seek to understand the role of externalisation at a
more theoretical level. In particular, we will make use of
cognitive models that attempt to deal with both more
explicit, conscious (rational) thinking and also more tacit,
unconscious, associative processes.
By doing this we add another dualism to the
interior/exterior dualism already implicit in the term
externalisation. Both distinctions risk offending many who
work in the areas most central to our concerns, who often
seek to breakdown such distinctions and take a more
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holistic view of self and action.
However, we believe that by
making such distinctions,
however problematic and
nuanced, we are better able to
understand the whole.
This structured and theoretical
analysis will, we hope, offer grounding for more practical
interventions. However, it is part of an ongoing process;
we do not expect it to be complete and final, neither
theoretically or practically.
This paper will begin by considering some of the
theoretical roots of externalisation and reflection. This is
followed by a section focussed more on practice, and the
different forms of externalisation in design. The fourth
section discusses the kinds of interactions facilitated by
externalisation: with the world, with other people and with
oneself. Finally, we consider what externalisation does: its
functions and the way these can be enhanced in tools and
techniques for design and creativity.
Externalisation most obviously connects with theories of
embodied or external cognition, which in different ways
emphasise the role of the external environment in human
cognition. These have become popular in recent years
drawing on a number of sources.
In philosophy, Heidegger's "Being and Time"  and
Merleau–Ponty's "Phenomenology of Perception"  have
both been influential focusing on our unconsidered, yet
artful, interactions with the world in contrast to more
traditional dualistic/mentalistic models from Descartes
onwards that prioritised the interior self . Many
modern philosophers draw on concepts of embodiment,
albeit with very different emphases, including Clark ,
Gallagher  and Varela .
In psychology, Gibson's "The Ecological Approach to
Visual Perception"  suggested that perception was far
more intimately tied to action than had previously been
considered and his concept of affordance has become
heavily used within human-computer interaction (HCI)
research and user-interface design [23,28,41]. Also ideas
of embodiment are being explored within neuroscience
using a combination of traditional experimentation and
brain scanning technology to investigate to what extent
perceptions are represented directly within motor areas of
the brain .
Building on roots in social anthropology and
ethnomethodology respectively, the concepts of distributed
cognition [33,31] and situated action  have been
influential in HCI since its beginning as a discipline.
Distributed cognition emphasises that we do not simply
think in our heads, but actively use the world in 'problem
solving', for example, moving the pieces of a jigsaw puzzle
not just staring at them. Furthermore, cognition may be
socially distributed; for example
an early study examined
Peloponnesian navigators who
traverse vast areas of sea
without modern aids, yet no
single individual holds
everything in their head, instead,
through working together as a
group, navigation happens. Situated action is similar,
emphasising the way we do not come to situations with pre-
made plans, but instead work out what to do based on the
exigencies of the moment.
Most of these positions focus on the largely unconsidered
moment-to-moment interactions with the world. As we lift
a cup, or walk down the road, we are not actively and
consciously lifting our arm, or swinging our leg, we just do
it. Heidegger calls this thrownness and contrasts it with
breakdown when we become explicitly aware of the actions
we perform and tools that we use. While at one level this is
merely descriptive, there is often also an implicit or explicit
value judgement, whereby breakdown has pejorative or, at
best, undesirable connotations.
It is clear that thrownness and artful interaction is crucial
when dealing with many forms of external representation.
For example, in drama and dance, while expert improvisers
are able to reflect whilst improvising, most performers will
not move as fluidly when thinking about their own actions.
Similarly an interface designer may want to walk through
an interface as she would imagine a user will do, but, if she
thinks about what she is doing, she will simply make the
same assumptions as she did while building the prototype.
However, we will see in later sections that breakdown is
also an essential part of externalisation and reflection, and
we will present a class of practical techniques aimed at
engineering breakdown at appropriate points.
Kinds of Knowing: Tacit and Explicit
This distinction between thrownness and breakdown, can
be seen as essentially that between tacit compared with
more explicit understanding and cognition.
There are a variety of closely overlapping terms used in this
area, and the distinctions are often less hard-edged when
examined in detail. However we can characterise these
modes in terms of common attributes.
Tacit knowledge and action is unconscious, in the sense
that we act without consciously thinking about it, although
the term 'unconscious' has many Freudian connotations, so
is often avoided. Gallagher use the more neutral term pre-
noetic . It is the more ancient mode of reasoning we
share largely with animals, based on associative/analogical
reasoning and builds naturally on neural mechanisms.
Learning tends to be slow requiring many examples and
trial and error, and is heavily affected by strength of
emotion. However, the slow building through multiple
exposures means tacit knowledge often has a probabilistic
nature, which we are particularly bad at consciously
"How does something that begins as an idea
or image in the mind become material?
How is the work of the hand influenced by
movements of the mind and vice versa?"
David Levi Strauss, From Head to Heart 
without external aids. The strength of this tacit probabilistic
learning was demonstrated in simulated gambling
experiments where participants showed galvanic skin
response to card stacks with different payoffs well before
they were able to explicitly distinguish them .
Tacit knowledge tends to be relational rather than
categorical/denotational, however that is not to say there is
no categorisation. As is evident in Lakoff 's work ,
categorisation of some sort is essential for associative
thinking, otherwise we could not generalise from past
actions. However, associative 'categories' may be more
soft-edged bundles of related things that tend to activate
together – that is no 'grandmother' neuron ... even though
there is a 'grandmother' word.
In contrast explicit knowledge and action, is consciously
available, we know we are doing it. It tends to be more
rational/logical and based on discrete categories that are
typically associated with words. Indeed there is a close
relationship between this kind of thinking and language;
however, while language appears to be necessary for
'higher' thought (as is evident from wild children brought
up with no language), it is also evident that we are not
limited to thinking within the existing vocabulary .
Furthermore, the categories of explicit thought, while being
available for discussion, are often based as much on fuzzy
(tacit) connotations as on precise denotations. While
learning itself is tacit (we cannot simply tell ourselves
'remember'), explicit conscious thinking tends to lead to
single-example learning through abduction or other forms
of reasoning. The associative learning of tacit knowledge
is old/primitive; in contrast explicit reasoning is a uniquely
or at least largely human attribute. From a computational
view, it builds awkwardly upon the neural substrate, which
is naturally associative, and must be very expensive in
terms of brain capacity used. This 'hardware' cost suggests
that has been of considerable value in our development as a
While there are contrasts between the tacit and explicit, we
should avoid simplistic dualism. Different philosophical
approaches prioritise one or the other, and popular
literature is full of advice on how to 'turn off' more rational
decision processes to let intuition take prime place [20, 26].
However, we are not schizophrenic with Jekyll and Hyde
personalities vying for control, but rather both kinds of
thinking contribute to our cognitive makeup.
Proponents of embodiment emphasise the way that what we
think of consciously, what springs to mind, is not under
conscious control; it is pre-noetic . Similarly, while the
interpretations are not unproblematic, Libet's frequently
cited experiments show that certain actions we might have
thought were under conscious decision making are in fact
'already decided' unconsciously before we are aware of
them . While framed in terms of 'free will', the actions
studied in these experiment, spontaneous but arbitrary hand
movement, are at best peripheral to any core idea of
personal choice. However, even these experiments show
that the conscious mind gets a chance to 'veto' unconscious
action; hence it has been argued we don't have 'free will',
but do have 'free won't' .
Complex emotions often involve a combination of more
logical/rational thinking and unconscious processes. For
example, when experiencing regret one makes a complex
counter-factual assessment of what would have happened if
one had acted differently and how likely this would have
been to lead to a different result. However, this complex
processing drives an emotional response and hence
subconscious associative learning .
In a deep review and critique of the psychological
embodiment literature, Wilson presents a rich picture 
where, on the one hand, pure embodied (and tacit)
explanations fail to account for common cognitive
activities such as planning, yet, on the other hand, virtually
all aspects of 'pure' cognitive activity, from memory to
reasoning are found to have physical/bodily aspects at play.
This mixing of unconscious and conscious is also common
in design where ideas seem to come to mind without
conscious thought, yet are evaluated, critiqued and
developed in a more rational mind.
Breakdown and Reflection
As has been noted, breakdown gets a bad press in the
embodiment literature. However, this seems to be the heart
of the reflective practice that is seen as the ideal in Schön's
work . Schön describes three levels of expert knowing:
knowing in action, reflection in action, and reflection on
action. However, all of these, Schö n is keen to point out,
differ from abstracted bodies of knowledge applied
acontextually to problems in what he terms 'Technical
The first kind, knowing in action, is not unlike thrownness:
referring to knowing that is "ordinarily tacit" and "implicit
in our patterns of action". This lived knowledge involves
"innumerable judgements of quality" without criteria that
can be explicitly stated and skills without explicit rules or
procedures. In terms reminiscent of Heidegger, Schön says
our "knowing is in our action" [47, p.49].
However, the professional does not stop there, but engages
in reflection in action monitoring and becoming explicitly
aware of the situation and "the prior understandings which
have been implicit in his behaviour", being open to
"surprise, puzzlement or confusion" [47, p.68]. This is, in
Heideggerian terms, clearly breakdown, yet regarded by
Schön as constructive, allowing the professional to attain
This mix of conscious and unconscious, rational and associative,
thinking is used in the 'principle of least regret'. Normally when
making a decision, one considers how good each course would
be and weighs these up. Instead one can envisage having taken
each action and imagine the regret felt at not having done the
alternatives – you choose the action with least regret.
deeper understanding of the situation and step out of
Finally, the most successful professionals engage in
'reflection on action', long-term growth through reflecting
on practices and processes. This is far rarer than knowing
in action or reflection in action indeed Schön sees a
weakness in many practical management schools because
managers "have little access to their own reflection in
action" [47, p.243], and therefore cannot pass on this
knowledge to others.
EXTERNALISATION IN DESIGN
The Ubiquity of Externality
External representations are ubiquitous in design and all
In architecture, we see plans, models, and also formal
procedures of consultations and deliverables to clients. In
product design we also see sketches and, because the end
product is human scale, full-scale mock-ups in blue foam,
cardboard or 3D printing, culminating in many cases, with
the production-line mould. In addition, both disciplines use
CAD and other forms of simulation or virtual walkthrough,
as do various kinds of engineers.
Some artists, particularly painters and sculptors, have no
external representation other than the nascent form of the
ultimate product. However, many employ some form of
sketch and may use mood boards or other means to
familiarise themselves with the emotional and physical
aspects of a brief.
Outside the visual arts it is common for the output of the
artist to be some form of intermediate representation (book
or score) before the actual performance of the work
(reading, or playing). However, again there are often
preliminary representations. Poets and song-makers make
many drafts and some cut out words and phrases to shuffle
around seeking inspiration or simply serendipity (if the two
are separable). A composer may hum bars, or sit at a
keyboard playing stray notes whilst penning then striking
out notes on the stave. Furthermore the performance of a
play, opera or symphony all are accomplished, Cage
included, in the external sound, silence and sights they
In the crafts, as in industrial design, sketches, models and
mood boards are common, as are more precise
representations such as the scale drawings used in carpentry
to plan complex joints, or the 'drafts' used in weaving to
turn the desired appearance of the fabric into the pattern of
warp threading and sheds.
In software engineering external forms abound from the
simple flow diagram to the multifarious notations of UML.
Indeed, now that electronic music and various forms of
performance are deeply embedded in software, composers
and artists may find themselves manipulating box and
arrow diagrams rather than physical instruments and
Within user interface design there are representations of the
systems being designed with paper prototypes and
storyboards as well as representations of the users and their
use situations in personae and scenarios.
The mathematician, is lost without blackboards or
notebooks full of diagrams, equations and scribbled notes.
And for all, there is always the paper napkin.
Uses of externalisation in the design process
These different forms of external entities address different
facets of design.
product – The most obvious external artefacts are the
products of design itself or representations of them:
sketches, models, prototypes. These have many functions
including communicating to clients, and testing how ideas
pan-out in practice. In the case of communicating to
others, the design may be close to final form. However,
concrete external representations of products can also be
more experimental. Indeed both Schon  and Alexander
, use scientific language when talking of this: the
concrete design as an 'experiment' or 'hypothesis'.
problem space – External representations can also be used
to express the problem to be solved or the context in which
the design is to be placed. Mood boards are an example of
this, not specifying a specific design, but communicating
the values and ethos of an organisation or of a setting.
Similarly a requirements specification creates an explicit
statement of aspects of the context. Alexander  regards
design as obtaining a fit between form (product/artefact)
and context, and describes the diagrams, which are the core
of his conception of 'patterns', as a "way of representing
design problems". The problem space can be both very
concrete, for example, photographs of an intended location
for a work of art, or in the case of Quist and Petra's
conversation in Schon  the physical structure of the site
of a school. However, it can also be very abstract, for
example the precise formal software requirements
specification, or the suggestive impressions from collecting
cultural probes .
Of course in representing the problem space, it can become
itself problematic, something to be 'designed', and it is this
reframing of the problem, which Schon considers one of
the hallmarks of a 'reflective practioner' [47, p:40].
design space – While a sketch or prototype represents a
single design possibility, some representations represent
aspects of a whole set of possibilities for the eventual
product. This can be done quite concretely by a series of
alternative designs, which in someway cover or sample the
set of possible designs. However, it may be abstract, for
example lists of criteria, properties, options: design
rationale notations such as QOC attempt to express the
choices for a design  and the Bad Ideas method, by
prompting one to consider why an idea is bad (or good),
forces one to articulate criteria . In some ways the
problem space and design space are doing a similar thing,
the former focused on the context, but using that to set
constraints on the design, the later transforming those
external constraints into criteria and properties of the
product of design. However, some issues arise only in
representations of the design space, for example, the
external (problem) constraints for a chair may be about
weight, strength and comfort, but choice of material, while
impacting these external constraints, may not be an explicit
part of the problem.
The nature of materials and tools has a profound impact on
the kinds of externalisations produced. In studies of group
design using different materials, it was noticeable that those
with plasticine or cardboard and glue, tended to explore the
design space by way of example, whereas those with paper
and pencil, tended to create more abstract lists of properties
process – Finally, one may have some form of
representation of the process being followed. This may be
a post-hoc record or some sort of plan or normative
schedule. For example, architects follow a prescribed set
of stages and in biology and chemistry laboratories the lab
notebook is a central part of the activity crucial for
intellectual property reasons, but also because of the
necessity to be able to reproduce precisely the same
conditions in future.
For some artists, for example, Andy Goldsworthy's
manipulations of the natural world, it is as much the record
of the process of construction as it is the final artefact that
comprises the work of art itself.
Properties and Dimensions
The physical and semiotic nature of these external artefacts
and representations also differ in various ways:
representation – Some external artefacts are physical and
in some sense isomorphic with at least aspects of the things
being designed, for example, the foam model of the product
designer, or (in a different modality) the hummed notes of
the composer. Some are more schematic or representative
such as the sketch or floor plan: in some ways rendering
aspects of the final item and yet in a different medium, or
some way distanced from it. Finally are more symbolic
representations such as the words in a mind-map, or
equations on the blackboard, which deal more with more
abstract concepts, ideas, criteria or properties.
modality – The forms of externalisation differ also in the
modality in which they are expressed. There is written
language, both normal language and also specialised
languages such as mathematical or musical notation. These
are typically abstract and symbolic. In addition, language
may be used in speech, whether as part of a discussion,
dictaphone notes, or speaking out loud a poem or other
work in progress. There are also drawn diagrams, sketches
or images, some more abstract or schematic, others closer
in form to the final product. Similarly there may be aural
representations (playing music), or even olfactory or tactile
externalisations, usually also close in form the final
product. Finally the externalisation may be done using the
whole body when acting out scenarios or body-storming
persistence – Some externalisations are naturally
persistent: the words written on a page, the clay model, or
the sketch on the back of an envelope. However, some are
ephemeral and past as soon as they are framed: the words
in a conversation, the notes played on a keyboard, or the
movements made during an improvisation session. These
two flow into one another when the ephemeral leaves
traces: patterns of footsteps on the sand, peeing on snow
, or whiteboard sketches at the end of a meeting. Indeed
one class of techniques we will see later is precisely those
that help create traces for discussion and reflection.
EXTERNALISATION AS INTERACTION
To understand how externalisation works as part of activity
in general and design in particular, we first need to realise
that while interconnected there are many different
processes at work involving physical, social and cognitive
interacting with the world
Physical externalisations offer opportunities and resistances
because of their physical nature. When a concept, an object
of mind, becomes solid it becomes subject to the same laws
as objects of nature and the resistances of the world form
the outcome as much as the initial mental idea. This is
exactly the process described by Sennett as a conversation
with materials .
This is often tacit and it is exactly this continuous
interaction with the environment that is emphasised by
those who argue for the centrality of embodiment or
enactment in all human activity. For example, Gibson
suggests that perception is not static, but is continuously
created through interacting with physical things and
moving in the physical environment : we can tell the
distance of an object by the way in which its edges change
as we move our head or move towards it.
However, in a design setting, externalisations may be
explicitly created in the form of scale models or diagrams
in order to exploit physical resistance; for example, by
looking at an architectural model, we may realise that a
window is facing a wall, or that there is no room for the
Sometimes this kind of limitation is only realised when an
exact scale (or real size) model is acted out in a real
scenario. For example, [16, p.202] describes a discussion
around the design of an Internet-enabled Swiss army knife.
The idea was that useful tips could be shared via a web site
and step-by-step instructions for using different blades
would be displayed on a small screen on the side of the
knife, using the toothpick as a stylus. While discussing this
verbally it sounded fine, it was only when acted out that it
became apparent that at a critical moment the fingers
holding the knife would obscure the display.
However, sometimes simply seeing a representation may
enable us to imagine limitations, or constraints or
opportunities. For example, the architecture pupil Petra
described by Schon [47, p.83] creates a scale drawing of a
school with six classrooms arranged in a staggered form,
but realises that these are too "small in scale" and so
instead changes them into three L shaped configurations.
Similarly, in a study where groups were given different
materials to work with, those with card tended to create
designs around flat or cylindrical (rolled) shapes .
Figure 1. Card suggests tubes and sheets (from )
These constraints of the world are also evident in less
physical situations. For example, in writing this paper it
may only be by formatting it in the appropriate style that
we discover if it is the right length, or that figures need to
be shifted to layout neatly. Similarly, in drawing UML
diagrams of a piece of software the tangle of lines may
suggest that there is insufficient modularity.
Many design situations now involve some form of virtual
model, whether 3D CAD or a traffic simulation. Here
computation does the job of the world in offering resistance
or 'talking back'. As with physical objects this may be
because it recruits the designers own understanding (e.g.
walking through a virtual building) or may that the
computation does the work (e.g. structural models). Of
course, in the case of code, the final output is virtual, but
equally a medium to be worked with and against; indeed
Sennett views the coder as much a craftsman as the
carpenter . This is evident in vignette 1, where Xara
finds that comparing outputs of her program helps her 'feel'
interacting with others
The importance of shared representations is a common
theme in ethnographies. In Heath and Luff's classic study
of the London Underground control room , the 'fixed
line diagram', a large display visible to everyone, shows the
locations of trains, track and signals and acts as a common
point of reference. Equally, more recent studies of the
home reveal a rich collection of resources for shared
coordination, from calendars and notice boards, to working
out who is at home from the keys in a bowl .
Non-physical externalisations are also critical. Star's
original conception of 'boundary objects' centred on the use
of a shared taxonomy, a conceptual 'object', as the means
by which diverse professionals in a museum environment
could interact . Similarly in vignette 2, Betty is able to
read Yorick's written argument and thus critique it.
Furthermore, she is able to listen to his verbalisation and
reflect back aspects of the argumentation that were absent
in the written externalisation, but present in his spoken
This last point is worth pausing upon. Quite naturally,
many people find it easier to speak than to write, as the
latter is a more complex skill. However, it is often hard to
'hear' one's own words. The authors have frequently
observed that simply reflecting back a student's own words
yields reactions such as "I never knew that". We will
return to this when considering externalisation tools and
Interacting with oneself
As well as being a way to interact with the world and with
others, externalisation can be a means to interact with
oneself both at the moment or in the future. This may
sometimes be an 'accident' of externalisation for others, as
one communicates with others one elaborates and thus
understands an issue better. It may also arise out of
Vignette 1: Xara's work involves writing simulations of
large-scale software. Because of the complexity of the
systems involved it is often hard to understand why
particular outputs are produced, even when everything
is working correctly. Albert has encouraged her to write
and update documentation of her code including
example outputs, this was largely to help her to obtain a
better understanding of her own code through the
process of documentation. Some months after starting
this process she remarks on the insight she obtained by
comparing different versions of the document and in
particular the different outputs produced. As the code
was evolving, the same input data produced different
outputs over time. Through seeing this, she expresses a
changing understanding of the underlying algorithms:
she says she is beginning to "feel" the code rather than
simply being able to calculate.
Vignette 2: Yorick has been writing a paper on the
1970's Cod War in the North Atlantic and is discussing
it with Betty. Betty picks on a few paragraphs near the
beginning of the paper as they appear to represent
related issues and examples, but without an obvious
argument structure, and starts to dissect them. On a
sentence-by-sentence basis she asks why each is there
and how it relates to the argument as a whole. She also
asks Yorick to say in words what he is trying to express
in the text. Yorick's verbal explanation includes
substantially more detail and rationale than in the text.
Betty realises that some issues mentioned in the text
that she had initially thought irrelevant were in fact part
of an argument and she reflects back what she believes
to be the underlying argument of the section. Although
he had not previously articulated this argument either in
the text or verbally, Yorick recognises this was indeed
an accurate reflection of the previously implicit
feelings he had of the situation.
interaction with the world, for example, after seeing the
thumb over the Swiss army knife 'screen' the importance of
how you hold devices became more salient.
Notes, plans and diaries are ways in which we externalise
now something that we believe will be of value to us in the
future. Unlike externalisations for others, which rely on
some form of common ground  or inter-subjectivity,
externalisation for oneself may only need a word, icon or
sketch that reminds one, a form of semi-private language.
For example, Threadway reports how the textile artist
Charlotte Hodes keeps a log of "handwritten notes and
sketches", which are "nebulous thoughts" and so
"sufficiently fluid to enable free exploration of visual ideas"
Talking across boundaries
Returning to the inter-personal use of external
representations, it may be driven by tacit or explicit
knowledge and evoke both tacit and explicit responses.
The prototypical 'informational' (see next section) human–
human conversation, especially in academic discourse, is
effectively acting at an explicit–explicit level: the
communication involves explicit thinking, representation
and interpretation on both sides. However, there is always
a level of tacit understanding in even the most apparently
explicit interchange, as highlighted in Herb Clark's notion
of establishing and negotiating common ground [8, 9].
In contrast a tacit–tacit level of intercourse is the primary
and ostensive purpose of externalisation in many of the
arts: a painting may convey emotions, or a poetic metaphor
express rich associations. However, tacit–tacit interactions
are also common in day-to-day experiences, from holding
out a shopping bag for another to fill, to dancing together at
a nightclub. Cultural probes can also act in this mode.
Using the probe packs, participants take photos, fill out
postcards, and otherwise create external artefacts. When
returned, the completed probes are placed in the designers'
workspace and serve to enculture them; while they may use
the probes more analytically (tacit–explicit), they often
simply soak in the atmosphere created by the probes
Externalisation may reach across the explicit–tacit divide.
In advertising and in design aimed at motivation or
persuasion  there is an explicit creation of an external
representation (image, object, game), which is intended to
create a tacit response: in the case of advertising often
appealing to desires, emotions; in the case of motivational
design maybe attempting to encourage positive feelings
about exercise, or make healthy eating seem cool. The use
of mood boards for brands is another example of this: the
mood board is intended to evoke very specific feelings
about the corporate brand and image, so that those
Note 'semi-' in the sense that it neither need be perfectly private,
nor give rise to perfect recall, the two attributes that were the
subject of Wittgenstein's critique [59/Wi53])).
designing electronic and print materials can fit within the
brand without necessarily themselves explicitly thinking
about the brand values. Even in academic writing we may
have an explicit idea of the expected emotional impact of
writing: do we keep the reader in suspense, but risk
confusion, or 'give away' the whole story in the abstract?
Finally, and perhaps most interesting, externalisations can
make tacit understanding available to explicit interrogation
by others. Looking again at vignette V2, Yorick verbally
expresses an argument, which is then reflected back and
elaborated by Betty. Although Betty also adds to the
argument, she also hears elements in Yorick's verbalisation,
which he clearly 'knew' tacitly in the sense that he said
them, but did not know explicitly enough to articulate.
Similarly in the arts one may analyse a poem exposing the
subtle use of metre and language by which it creates its
emotive effects. We will return to this tacit–explicit mode
later when we re-examine reflection.
Table. 1. Modes of interaction with others
Table 1 summarises these modes of explict/implict
communications. However, this itself, while avoiding the
dualism that separates these completely, still runs the risk
of over simplifying. Where would one put Derrida in such
a picture? Even Einstein's imaginary 'sitting on a light
beam' strains the boundaries.
Functions of Externalisation
So far we have looked at examples of externalisation, seen
it as a rich process, which often involves many layers of
action and thought at the same time, and seen how it
operates within and across the tacit–explicit divide.
However, externalisation is not a purposeless phenomenon,
but something that achieves something. We identify four
functions of externalisation:
informational – This is the obvious explicit–explicit
communicative function of writing, noted in the last
section: you have some existing thoughts or ideas and set
these down on paper so that someone else can understand
the same things that you do (Figure 2). Similarly an
architect may make a scale model or virtual reality
simulation in order to convey the shape, appearance or
experience of a building to a client. Note that this process
may not be perfect. The words or pictures on the paper, or
model on the table may not perfectly capture the idea or
picture in your head. Similarly, the impression that this
creates in your readers' or clients' heads may be not be the
same as in your own. However, whilst not a perfect act of
communication, it is achieving a communicative purpose.
Figure 2. informational – passing on to others already formed
formational – Most writers have noticed the common yet
strange phenomenon that they know more after they have
written than they did before. This is weird if one regards
externalisation solely as an act of communication. The act
of writing demands a particular word, the need to sketch
demands that the location of a door is specified; what had
been vague or fuzzy thoughts becomes specific and
concrete; the very process of elaboration of thoughts
changes the thoughts. Rather then pre-existing ideas being
re-presented in an external form, the idea is itself formed in
the process of presentation. This can be problematic
leading to premature commitment, hence the need at some
stages of design for deliberately fuzzy representations; for
example, Buxton  emphasises the importance of the way
sketched lines are imprecise and often don't join at the
Figure 3. formational – vague ideas becoming clearer
by the process of externalisation
transformational – While the informational function is
most obvious when considering communication media, for
those involved in craft or product design the most
important thing is that the external representation has
properties that can be used to help in understanding or
planning the eventual outcome. We may measure lengths
on a scale diagram, add up lists of numbers, play back a
tune, or simply run our hands over the planned shape of the
wing of a car. Sennett  talks about the relationship
between craftsman and material as a form of conversation
and Schön  refers to the "back talk" of the situation,
part of knowing in action. In problem solving research it is
well known that changes of representation can offer
obvious solutions to what appeared to be intractable
problems, and perhaps this move from internal to external
is the most radical transformation of all. It is this function
of externalisation as an augmentation of cognitive activity
that is critical in distributed cognition accounts and in those
– This final meta-cognitive function is the
least obvious, but ultimately perhaps the most powerful.
Because our thoughts have been expressed externally we
can peruse them as if they were any other thing. This is
most obvious when we in some way capture the abstract
aspects: concepts, arguments, criteria, etc. In a mind map
one can see both the names of concepts written down and
also the relationships between them as connecting lines and
clustered word bubbles. In an academic paper, like this, one
can analyse the way the argument is structured and
recognise its strengths and gaps. This function is most
common with symbolic representations such as words, as
the symbols in some sense 'flatten' the conceptual
landscape: the word "stone" is similar to the word
"concept" or "efficiency"; so that talking about thoughts
and thoughts about thoughts become little different from
talking about feet or walking.
Fugure 5. transcendental – our thoughts and ideas
become the object of thought
Without minimising the importance of communication in
the informational function, or the embodied cognition of
the transformational function; we will shift our attention to
the formational and transcendental aspects as it is in these
that embodiment and reflection meet.
From knowing to knowing about knowing
It is the transcendental function of externalisation that we
see at work in accounts of professional reflection. Often
this is through the resistances felt through interactions with
others or with the world that then force reflection. Recall
Quist is the tutor architect in Schön . Quist and Petra
are discussing her initial ideas for the site and her
problems. Quist says, "You should begin with a discipline,
even if it is arbitrary, because the site is so screwy ...". The
odd patterns of contours in the site, its 'screwiness' forces
Quist to step back, consider and explicate higher-level
'Transcendental' here is being used in its meaning as a different
(higher) plane or level of reasoning, not in any mystical sense.
Figure 4. transformational – thinking using materials
heuristics. However, the
screwiness itself was evident not
from walking the terrain, but from
the representation in terms of
contour lines on the page. The
externalisation allows Quist's tacit
understanding of the spatial
characteristics to operate, noticing
the site feels 'screwy' and the by
articulating this, makes it available as an explicit issue to be
At a larger scale, Alexander's pattern language is doing just
this, reflecting on centuries of craft knowledge made
external in buildings and streets, and from that extracting
the patterns of events and spaces that make these 'work' for
people . Furthermore, by making these patterns explicit,
one can not only apply and teach them, but also discuss
them, maybe debate whether a particular pattern is right, or
how patterns fit together. Similarly, by naming his six 'S's
(site, structure, skin, services, space plan and stuff), Brand
was able to analyse and articulate the aspects of traditional
buildings that made them able to evolve . In music
theory also, Magnusson describes how the need to create
code means that digital instruments make explicit the
knowledge that was implicit in traditional analogue
At an even larger level this can be seen as the ultimate
success of language and the symbolic. Words allow us to
talk about things and so collaborate. However, words also
are things in themselves, identifiable on the page, and yet
remarkably similar in form no matter whether what they
represent is concrete or abstract, verb or adjective. In his
use of archaeology to uncover past human and pre-human
cognition, Mithen identifies the importance of cognitive
fluidity, the ability to work between multiple modular
intelligences (social, physical, etc.), which arose
somewhere between 30 and 60 thousand years ago .
This fluidity is necessary for material symbolism, and so
essential for language, thus language cannot be the sole
source for it. One of the authors has argued that
imagination acts as an alternative cognitive connection
between these modules, maybe kick-starting the process
Whatever the origins, language creates an important ratchet
as symbols and words are a great conceptual leveller. Once
they are external symbols, we can manipulate 'wolf' and
'worry', 'heavy' and 'health' as they are things not ideas or
concepts. At its extreme, this is precisely the agenda of the
formalist movement at the turn of the 19/20 century, but is
also the stuff of day-to-day language use. Language is one
of the core tools of the transcendental function of
externalisation, as it turns the world of ideas into the world
of material 'stuff', and thus allows us to have ideas about
ideas as easily as ideas about stuff, and those ideas about
ideas are named, become material and thus the subject of
discussion. At each stage the level
of discourse is raised, allowing us
to think more generically, more
Andy Clark sees language within a
framework of external mind, as a
sort of bringing of the external
word into the internal . The
external material symbols become available in our
imagination so are amenable to our internal means to
apprehend and deal easily with the external material world.
Some writers, such as Searle  stress the role of
language in creating reality, especially in establishing
institutional facts (Obama is the President of the United
States, because he was declared to be it), however Renfrew
notes that it is often "the material reality, the material
symbol, that takes precedence" [46, p.127]. It seems there
is a rich interplay whereby material realities shape
language, but language, while not in the end limiting
thought , does shape it, making some things easier to
say and think. This then changes material culture – the fact
that we have words for 'chair' and 'table' means we see the
world in these terms, and so the world becomes populated
with easily classifiable chairs and tables .
By understanding this rich interplay, it is possible to exploit
it, to expose our internal categories in our external actions,
and to use external tools to challenge those categories.
Tools and Methods
In general, understanding the ways in which externalisation
works, can help us make sense of various tools and
techniques for design and creativity, and moreover to
develop new ones.
tapping into the tacit – Some techniques work by
appealing directly to our tacit understanding. Rich
scenarios and personae do this. They are deliberately far
more detailed than crude user profiles including
'unnecessary' details that make the people and the physical
situation seem to real to us. By appealing to our
imagination, they spark our natural social and physical
understandings in a way that an abstracted 'user group'
cannot. Similarly (re)coding dialectic, provides a way for
analysts to validate and evolve their vocabulary, models or
categorisation schemes (whether these are based an a priori
theory or inductive methods) . The analyst is asked to
(re)code existing transcripts or observations with the
scheme. It is obvious that extra thought is required where
there are gaps. Less obviously, where a category (say 'X')
does apply, the analyst is prompted to say to themselves
"this item is just X" or "no more than X". This "just a"
phrase often sparks a visceral response "no it is not just an
X ..." and in explicating this tacit response, the scheme is
refined and developed.
resistance and breakdown – Another class of techniques
attempt to bring aspects of our tacit understanding of the
external world to our attention, problematising them, and so
making them available for reflection. Many artists,
"There are known knowns ...
We also know there are known unknowns; ...
But there are also unknown unknowns ..."
Donald Rumsfeld, 2002
When we tap into our tacit knowledge
we are uncovering the unknown knowns.
ethnographers and comedians are experts at estangement,
taking the everyday and making it in some way strange: a
focus of wonder, analysis or laughter; the things we take
for granted are instead granted centre stage.
This can become an explicit analytic method. In one
exercise, designers named and arranged the activities they
used in their personal design process, then, one-by-one, the
activities were removed and the designers reacted to the
envisaged loss . In Making Tea, chemists' use of lab
books was examined by asking them to make tea using both
chemistry and kitchen equipment, in each case treating the
exercise as if it were a laboratory procedure [48/sD09].
This created a common ground between researcher and
chemist, but also made the chemists' everyday, invisible
practices in the lab 'strange' and salient. The early stages of
Bad Ideas do the same, by asking participants to come up
with a bad or silly idea, rather than a good one, they
instantly find themselves in a strange part of the design
space, and so are able to see it more clearly .
In some areas near constant breakdown can have a positive
effect. In studies of novice object-oriented programmers,
simply asking them to vocalise during early design lead to
improved performance . This is also evident in pair
programming, which is popular in agile software
development methods .
reducing and relating – When words or symbols are on
paper, they become available, but often need to be brought
together to see similarities and differences, to bring out
commonality or explore conflicts. The codes used in
content analysis and grounded theory, do this for transcript
data. The transcripts (or video/audio recordings which they
record), may be to large to apprehend, but when reduced to
a stream of codes relationships themes and higher order
categories become evident. We see this in vignette 3 where
Zoe becomes aware of cross cutting categories due to
similar names and words. A similar technique can be used
in dealing with reviews of literature, software or products.
By using a few bullet points to capture the salient points of
each item, what was a huge pile of papers, documentation,
or objects gets reduced to a few A4 sheets of paper –
similar terms in bullet points become apparent and thematic
concepts, that were clearly there tacitly in that they were
used to write the bullet points, suddenly become explicit.
engagement and reflection – There is often a tension: to let
our tacit skills work we need thrownness, engagement in
what we are doing, but reflection can get in the way of this.
If a poet were to think at the end of each line, "I wonder
what poetic techniques I have used", it is unlikely more
than one line would get written. Where the externalisation
is persistent: on paper, in clay, or captured digitally, then
this tension can be resolved partially by separating in time
thrownness and breakdown, action and reflection: the poet
may write then critique, the painter stands back.
For more analytic processes whether exploring a design
brief, establishing user requirements, or academic research,
reflection is often achieved through text. We have already
noted how simply reflecting back students' words can elicit
surprise, as if the idea was new. This is particularly the
case with abstract and relational concepts; students know
about the concrete nouns and noun categories that they use,
but are less likely to recognise the adjectives, criteria and
property words – even though they speak them. In
requirements engineering it is common to perform noun-
verb analysis on written materials (documentation, manuals
etc.). In a similar way it is possible to analyse one's own
writing and examine critically the vocabulary. This is a
common weakness of mind maps, which tend to focus on
nouns and concrete classes; but explicitly naming the
linking lines and arrows may yield new insights.
tracing the ephemeral – This separation works when the
externalisation is persistent: writing, drawing, sculpting,
modelling; but fails for the ephemeral: spoken words,
improvised dance or music, drama or body storming. A
facilitator or observer may aid this, so that the actor (the
person engaged in tacit action) can continue unreflectively,
while the observer watches for novel ideas and issues. For
example, training simulators have been developed for
special forces to develop cultural sensitivity; some
participants take active roles, while others observe; in
addition facilitators draw the observers' attention to
interesting points . In this case the active participants
are not reflecting themselves, it is more that their actions,
would be similar to those of the observer so provoking self-
reflection on the part of the (novice) observers.
When the performer needs to reflect on their own
performance or when the action happens too quickly for
effective observation, some form of recording is needed,
laying down a trace where there is none naturally. This is
exactly what is seen in physical sports where trainers will
film athletes, and then watch alongside one another in order
to improve their performance. Note that this involves three
phases: first through recording and observing making tacit
Vignette 3: Zoe engaged in an extensive qualitative
study of libraries using grounded theory. She studied
different libraries then analysed each separately using
grounded theory and is finally bringing the results
together. To do this she reduced the rich descriptions of
each category and sub-category to simple lists in a
spreadsheet so that similar concepts can be identified in
the different libraries studied. However, in doing this,
she notices that even within a single library's results,
there are sub-concepts with very similar names
appearing under different concepts: for example,
"oversize books" occurs under "shelving" and "large
books" under "scanning during check-out/check-in".
This at first appears to be a problem in the analysis, but
in discussing this with Charles, they realise that in fact
this corresponds to a cross-cutting issue, that of the
physical properties of books, which should perhaps be a
concept in its own right that has inter-relationships with
other concepts such as "shelving" and "scanning".
behaviour available for explicit reflection, then through
explicit analysis working out improved techniques, finally
the explicitly understood techniques have to be practiced so
that they are committed to tacit 'muscle memory'. This
same process can be used in more cognitive design
situations, for example, simply recording conversations (or
learning to type and note-take less reflectively) so that the
resulting written trace can be later examined in a more
In the Replay method , observation and video recording
are used during dramatic and design-focused improvisation,
both forms of ephemeral externalisation. By asking some
actors to take a more reflective role, they become like the
tutor or trainer, observing and eliciting interesting issues,
themes or ideas from the otherwise fleeting actions of the
other actors. Recordings are later replayed for further
reflection by the group. Similar techniques are used in
cooperative evaluation and video-based user evaluations of
user interfaces , and cultural probes, as well as their
tacit–tacit role, also act as ways of recording (albeit with
disruption) the quintessence of the quotidian for later
Externalisation is ubiquitous in design and it is important to
understand its role so that we can make the most of it, and
develop ways to improve its power. However, there is a
theoretical and practical tension between external
representation as part of embodied action and as a means
for reflection. We have shown how externalisation is in
fact a link point between the tacit and explicit, enabling
unreflective embodied action to become the subject of
analytic reflection. This analysis offers a way to
understand, refine and develop practical design and
creativity techniques. This paper is itself effectively a meta-
reflection, and we hope by exposing these issues they can
become part of the tacit as well as explicit understanding
we bring to bear on our understanding of practical design.
This work is part of the DESIRE ITN (desirenetwork.eu).
Thanks also for comments from Linden Ball and reviewers.
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