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  <front>
    <journal-meta />
    <article-meta>
      <title-group>
        <article-title>When Reflective Feedback Triggers Goal Revision: a Computational Model for Literary Creativity</article-title>
      </title-group>
      <contrib-group>
        <contrib contrib-type="author">
          <string-name>Pablo Gerva´ s</string-name>
          <email>pgervas@sip.ucm.es</email>
          <xref ref-type="aff" rid="aff1">1</xref>
        </contrib>
        <contrib contrib-type="author">
          <string-name>Carlos Leo´ n</string-name>
          <email>cleon@fdi.ucm.es</email>
          <xref ref-type="aff" rid="aff0">0</xref>
        </contrib>
        <aff id="aff0">
          <label>0</label>
          <institution>Facultad de Informa ́tica, Universidad Complutense de Madrid</institution>
          ,
          <addr-line>28040 Madrid</addr-line>
          ,
          <country country="ES">Spain</country>
        </aff>
        <aff id="aff1">
          <label>1</label>
          <institution>Instituto de Tecnolog ́ıa del Conocimiento, Universidad Complutense de Madrid</institution>
          ,
          <addr-line>28040 Madrid</addr-line>
          ,
          <country country="ES">Spain</country>
        </aff>
      </contrib-group>
      <fpage>32</fpage>
      <lpage>39</lpage>
      <abstract>
        <p>Existing models of the writing task from a cognitive viewpoint agree on the importance of draft revision in the overall process. This is generally assumed to focus on reviewing intermediate drafts in search for feedback on how to modify them to match the driving constraints. However, in literary creativity it is often the case that the feedback leads not to a revision of the current draft but to a redefinition of the constraints that are driving the process. This phenomenon is explicitly described in Sharples' model of writing as a creative task. Yet existing computational models of literary creativity do not contemplate it. The present paper describes a computational model of the creative processes in literary creativity that contemplates the explicit representation of the constraints driving the process, and allows for the feedback from the validation to modify not just the ongoing draft but also the constraints that it is expected to satisfy. This allows the model to represent cases of serendipitous discovery of interesting features. This paper has been partially supported by the project WHIM 611560 funded by the European Commission, Framework Program 7, the ICT theme, and the Future Emerging Technologies FET program.</p>
      </abstract>
    </article-meta>
  </front>
  <body>
    <sec id="sec-1">
      <title>-</title>
      <p>Creative processes as carried out by humans are known to
involve a significant amount of trial and error. Writers,
musicians, painters, poets... rely on a succession of drafts that get
polished over many iterations, each one involving feedback
from the previous version, and resulting from a process of
revision or regeneration of it. Yet computational models
developed in AI over the years to emulate these same processes
very rarely capture this type of dynamic operation.
Sometimes they do, in a limited fashion, when an AI program
includes an evaluation function that defines the desired form
for outcomes, and this is run over the results of a generative
process that produces candidate artefacts of the desired type.
However, the dynamics of the creative process in humans are
known to be more complex than this, possibly differing
significantly across different domains.</p>
      <p>The present paper focuses on literary creativity, and
proposes a computational model for the creative process in this
domain based on a number of cognitive model of the task of
writing as carried out by humans.
2</p>
    </sec>
    <sec id="sec-2">
      <title>Previous Work</title>
      <p>The present paper puts forward a proposal that captures in
computational terms the operations described in two existing
cognitive models of the writing tasks. This section reviews
these two models and two competing computational models
also based them.
2.1</p>
      <sec id="sec-2-1">
        <title>Cognitive Models of the Writing Task</title>
        <p>Flower and Hayes [Flower and Hayes, 1981] define a
cognitive model of writing in terms of three basic process:
planning, translating these ideas into text, and reviewing the result
with a view to improving it. These three processes are said to
operate interactively, guided by a monitor that activates one
or the other as needed. The planning process involves
generating ideas, but also setting goals that can later be taken into
account by all the other processes. The translating process
involves putting ideas into words, and implies dealing with
the restrictions and resources presented by the language to be
employed. The reviewing process involves evaluating the text
produced so far and revising it in accordance to the result of
the evaluation. Flower and Hayes’ model is oriented towards
models of communicative composition (such as writing
essays or functional texts), and it has little to say about literary
creativity in particular. Nevertheless, a computational model
of literary creativity would be better if it can be understood
in terms compatible with this cognitive model. An important
feature to be considered is that the complete model is framed
by what Flower and Hayes consider “the rhetorical problem”,
constituted by the rhetorical situation, the audience and the
writer’s goals.</p>
        <p>Sharples [Sharples, 1996] presents a description of writing
understood as a problem-solving process where the writer is
both a creative thinker and a designer of text. For Sharples,
the universe of concepts to be explored in the domain of
writing could be established in a generative way by exhaustively
applying the rules of grammar that define the set of
wellformed sentences. The conceptual space on which a writer
operates is a subset of this universe identified by a set of
constraints which define what is appropriate to the task at hand.
Sharples explains that the use of a conceptual space “eases
the burden of writing by limiting the scope of search through
long term memory to those concepts and schemas that are
appropriate to the task” [Sharples, 1996, p. 3]. To Sharples,
the imposition of these constraints enables creativity in the
sense that he identifies creativity in writing (in contrast with
simple novelty) with the application of processes that
manipulate these constraints, thereby exploring and
transforming the conceptual space that they define. Sharples provides
a specification of what he envisages these constraints to be.
Constraints on the writing task are described as “a
combination of the given task, external resources, and the writer’s
knowledge and experience” [Sharples, 1996, p. 1]. He also
mentions they can be external (essay topic, previously
written material, a set of publishers guidelines. . . ) or internal
(schemas, inter-related concepts, genres, and knowledge of
language that form the writer’s conceptual spaces).</p>
        <p>Sharples also provides a description of how the typical
writer alternates between the simple task of exploring the
conceptual space defined by a given set of constraints and the
more complex task of modifying such constraints to
transform the conceptual space. Sharples proposes a cyclic
process moving through two different phases: engagement and
reflection. During the engagement phase the constraints are
taken as given and the conceptual space defined by them is
simply explored, progressively generating new material.
During the reflection phase, the generated material is revised and
constraints may be transformed as a result of this revision.
Sharples also provides a model of how the reflection phase
may be analysed in terms of specific operations on the
various elements. A three step process of reviewing,
contemplating and planning the result is suggested as a description
of the reflection phase. During reviewing the result is read,
minor edits may be carried out, but most important it is
interpreted to represent “the procedures enacted during
composition as explicit knowledge which can then be integrated
with an existing conceptual space”. Contemplation involves
the process of operating on the results of this interpretation,
which are likely to be explicit representations of specific
constraints. Planning uses the results of contemplation to create
plans or intentions to guide the next phase of engagement.</p>
        <p>Sharples also provides an account of how the explicit
representation of constraints as elements susceptible of
modification is fundamental to achieve this type of cyclic
operation. People produce grammatically correct linguistic
utterances without being aware of the rules of grammar, but to
explore and transform conceptual spaces one needs to call
up constraints and schemas as explicit entities, and work on
them in a deliberate fashion. For the mind to be able to
manipulate the constraints, they have to be subjected to a process
of “representational redescription” [Karmiloff-Smith, 1995],
re-representing knowledge that was previously embedded in
effective procedures as elements susceptible of manipulation.</p>
        <p>The problem is that beginners addressing such a cognitive
task do not have a vocabulary to describe mental processes
to themselves. To learn, they must develop “a coherent
mental framework of plans, operators, genres and text types that
can guide the process of knowledge integration and
transformation” [Sharples, 1996, p. 5]. Experts tend to have such
a mental framework that underlies and supports their writing
efforts. For beginners, the problem must be addressed with
the aid of general knowledge about how to design artefacts,
how to transform mental structures and how to solve
problems. Because this is difficult to do in the head, some writers
resort to capturing the ideas involved in paper, as sketches,
lists, plans, notes etc. These external representations stand
for mental structures, and they are easier to manipulate. The
writer can then explore different ways of structuring the
content, apply systematic transformations, establish priorities,
and reorder or cluster items. The task of writing addressed
in these terms is much closer to recognised design tasks.</p>
        <p>The arguments outlined above with respect to how Sharples
models the differences between beginners and experts
suggests further consideration of the role of the evolution of
representation in the progressive acquisition of expertise. In this
respect, Karmiloff-Smith [Karmiloff-Smith, 1995] proposes
a model of evolving representation called Representational
Redescription model.</p>
        <p>This model analyses the development of behavioural
mastery in a given domain – meaning consistenly successful
performance in the domain – in terms of how knowledge about
the domain is represented internally by the individual. The
model considers three phases of learning. During the first
phase the individual focuses on his interaction with the
environment, and represents these in the form of raw data received
from outside. This may lead to an initial achievement of
behavioural mastery. Over the second phase, internal
representations are abstracted from the raw data, and processing may
start to focus on them. As a result of this introspection,
features of the environment may temporarily be disregarded and,
as a result, observed behaviour may deteriorate. However,
this leads to a recuperation of a more flexible achievement of
behavioural mastery, by then based on having achieved
reconciliation between internal representation and external data.</p>
        <p>This model describes four different levels of cognitive
representation: implicit, focused on the process itself; explicit
level one in which basic aggregation of raw data present in
the implicit level is performed in terms of data storage but
may not yet be accessible to the cognitive system for
manipulation operations; explicit level two, in which structures from
the first explicit level are converted into schemas and thereby
become available; and explicit level three, a final and
“crosssystem” representation of concepts that can be verbalized and
are fully integrated in a more general cognitive system.
2.2</p>
      </sec>
      <sec id="sec-2-2">
        <title>Existing Implementations of Sharples’ Model</title>
        <p>MEXICA [Pe´rez y Pe´rez, 1999] was a computer model
designed to study the creative process in writing in terms of the
cycle of engagement and reflection [Sharples, 1999]. It was
designed to generate short stories about the MEXICAS (also
wrongly known as Aztecs). MEXICA is a flexible tool where
the user can set the value of different parameters to constrain
the writing process and explore different aspects of story
generation. It takes into account emotional links and tensions
between the characters as means for driving and evaluating
ongoing stories.</p>
        <p>MEXICA relies on certain structures to represent its
knowledge: a set of story actions (defined in terms of
preconditions and post-conditions) and a set of previous stories
(stated in terms of story actions). MEXICA stands out from
other systems in that it actually builds its own set of schemas
from the set of previous stories. A single type of knowledge
structure, known as a Story-World Context (SWC), is used to
represent these schemas. Story-World Contexts represent
instances of contexts (described in terms of emotional links and
tensions between existing characters) in which an action has
appeared in a previous story, and they act like rules during
the engagement phase: an action is added to the plot if a
Story-World Context for that action can be found that matches
the plot so far.1 The reflection phase revises the plot so far,
mainly checking it for coherence, novelty and interest. The
checks for novelty and interest involve comparing the plot so
far with that of previous stories. If the story is too similar
to some previous one, or if its measure of interest compares
badly to previous stories, the system takes action by setting a
guideline to be obeyed during engagement. These guidelines
can be considered as a basic implementation of Sharples’
constraints, driving which types of action can be chosen from the
set of possible candidates.</p>
        <p>In MEXICA, the system is actually aware of the emotions
of all the characters (and the emotional tensions between
them) and uses these to drive and structure the story. But
these emotions and tensions are often not mentioned in the
final text of the story.
2.3</p>
      </sec>
      <sec id="sec-2-3">
        <title>The ICTIVS Model</title>
        <p>The ICTIVS model [Gerva´s and Leo´n, 2014] arose as an
1It is important to note that Story-World Contexts (and not the
definitions of action in terms of their pre-conditions) are used to find
the next action to extend the plot.
initial attempt to construct a theoretical model based on an
abstract analysis of the task of story construction in the
context of a basic communication situation. Figure 1 shows a
graphical representation of the ICTIVS model. The
communication takes place as an exchange of a linear sequence of
text that encodes a complex set of data that correspond to a
set of events that take place over a volume of space time,
possibly in simultaneous manner at more than one location. To
convey this complexity as a linear sequence and recover it
again at the other end of the communication process requires
a process of condensing it first into a message and then
expanding it again into a representation as close as possible to
the original. There is a composer, in charge of composing a
linear discourse from a conceptual source that may also have
been produced by himself, and an interpreter, faced with the
task of reconstructing a selected subset of the material in the
conceptual source as an interpretation of the received
narrative discourse. In real life, the role of the composer is usually
played by a writer and the role of interpreter by a reader, but
in the present case a more generic formulation has been
preferred for generality.</p>
        <p>This overarching act of communication is fundamental
because it allows the definition of the purpose of the task in
terms of the expected impact of the constructed story on the
interpreter. Whatever is produced by the composer will have
to be processed by the interpreter, and the impact on the
interpreter cannot in truth be considered without taking into
account what this process of interpretation involves. With
this premise in mind, the ICTIVS model [Gerva´s and Leo´n,
2014] started from a linear description of the complete act of
communication from an original purpose in the mind of the
composer to a final impression in the mind of the interpreter.
This act of communication involves processes of invention of
a message and composition of an appropriate form meant to
be carried out by the composer. It also involves processes
of interpretation and validation carried out by the interpreter.
From the point of view of the communicative act, the
measure of success of such an act of needs to be established in
terms of whether the interpretation by the interpreter matches
the message constructed by the composer – success in terms
of information transfer – and whether the impression in the
mind of the interpreter matches the original purpose of the
composer – success in terms of expected impact. As a first
approximation, the impression in the mind of the interpreter
could be correlated to the results of the validation applied to
the message. In order to capture this intuition, the ICTIVS
model defines the task of story composition as an iterative
cycle of revisions in which the composer progressively
generates drafts of his message, and then applies to them an
internal process of interpretation and validation intended to match
the one that the interpreter will be applying. At each iteration,
the results of this estimated interpretation/validation are
compared with the original purpose. If mismatches are detected,
another cycle is started, and only when a successful match
has been found does the resulting version of the message get
communicated to the intended audience.</p>
        <p>Five specific stages are included in the model:
INVENTION – coming up with content for the narrative, possibly
starting from scratch but often from some specification of
purpose; a composer task –, COMPOSITION – establishing a
form to express the desired content; a composer task –,
INTERPRETATION – given a story, fill in the gaps, connect
the dots, make assumptions on posible background implied,
and extend it into a full picture of what the author wants you
to “see in your mind”; an interpreter task that the composer
needs to model to generate informative feedback for the
construction process –, VALIDATION – identify the impact that
the story, and/or the material interpreted from it, has on the
interpreter; as above, an interpreter task but one that the
composer needs to model to provide feedback –, and
TRANSMISSION – passing over the result of the other processes to an
audience; this stage establishes the link between the composer
and the interpreter. Of these five stages, the first four may
take place in an iterative cycle, and the final stage occurs only
once after the iterations have lead to a successful draft with
potential for achieving the expected impact on the interpreter
according to the composer’s purpose.
3</p>
      </sec>
    </sec>
    <sec id="sec-3">
      <title>Reflective Feedback and Goal Revision in</title>
    </sec>
    <sec id="sec-4">
      <title>Computational Models of Literary</title>
    </sec>
    <sec id="sec-5">
      <title>Creativity</title>
      <p>The computational models reviewed in section 2.2 and 2.3
capture the essence of the cognitive models described in
section 2.1, but they both fail to capture the particular features
that concern feedback and goal revision. The model of
engagement and reflection in MEXICA has very limited
explicit representation of the constraints driving the process,
in the form of guidelines set during reflection. The ICTIVS
model as originally described was formulated at a more
abstract level, but focuses more on the constructive approach to
the creative process, with no explicit modelling of the task
of revising an already existing draft. It did include the
representation of a seed idea or meaning that the composer wants
to convey, but no representation of the possibility of this idea
being modified as part of the creative process. A refinement
on these models is required that can integrate a specification
of the purpose for the generation task as an input, that can
allow for revision of this specification as part of the process,
and that at the same time can take advantage of the existing
body of work on narrative generation.</p>
      <p>Three relevant insights arise from the consideration of the
original ICTIVS model in this enriched context of
purposedriven communication.</p>
      <p>First, there will probably be a significant difference in
computational terms between the initial iteration, where at each
stage new material is generated from the corresponding
input, and subsequent iterations, where two different processes
may need to be employed: further generation of new
material from the specification, and revision of the material
generated in previous iterations - where the revision needs to be
informed by the initial specification, the earlier drafts, and the
identified mismatches. This is important because the
computational mechanisms involved in each case may be different,
and also because outputs from these two different processes
may need to be combined into an integrated output for the
corresponding stage.</p>
      <p>Second, at the point of deciding whether a given draft is
successful in terms of how it matches the original purpose, a
truly creative process may consider not only revision of the
draft but also revision of the purpose. This may arise
whenever the estimated impact of a given draft on the interpreter is
considered valuable by the composer beyond his original
purpose. By means of this extension, the model can capture the
role of serendipity in the creative process [Pease et al., 2013;
Corneli et al., 2014].</p>
      <p>Third, although computational models of the creative task
are traditionally formulated as a cycle, in an ideal creative
process cross-fertilization across the type of stages defined
would be very positive. This is evident in Flower and Hayes
description of the process as a set of transitions between three
processes governed by an overall monitoring process that
allocates effort to each one of them, and in Sharples’ phrasing
of his model as a dual cycle between two stages that
operate on different data – the text and the constraints. A similar
abstraction will need to be considered in our model.</p>
      <p>The present section analyses these important concepts in
more detail and attempts an initial formulation of such a
refinement to take them into account in a manner that better
reflects the intuitions arising from the cognitive models.
3.1</p>
      <sec id="sec-5-1">
        <title>Analysing the Tasks Involved in Creative</title>
      </sec>
      <sec id="sec-5-2">
        <title>Production</title>
        <p>In order to identify the core features that the desired model
needs, the tasks involved in generation must be examined
explicitly and compared to what the models can currently
represent. Following this, we proposed a categorization of
generative system according to their capabilities in terms of
feedback.</p>
        <p>Regarding their internal process, four types of systems can
be identified:
those that take no input and generate outputs determined
exclusively by decisions taken during the construction
of the system (mere generation)
those that take as input some kind of specification that
determines in some way the type of output that is to be
obtained (specification)
those that include a module that quantifies in some way
the degree to which the outputs obtained satisfy the
requirements specified as input (diagnostic)
those that can benefit from the results of a diagnostic
module to modify the specification and self correct their
output (reflective)</p>
        <p>Taking into account the kind of input that the systems
accept, a parallel axis of classification may be whether the
system can generate outputs only by constructing them from
scratch (construction) or by applying transformations to an
initial version of the desired artefacts (revision).</p>
        <p>When these two axes are combined with the issues
described previously, the following set of possible modes of
operation arise:
mere construction: the system generates outputs of a
given form as determined by its construction
construction to a specification: the system generates
outputs conforming to a given specification
construction with diagnostic: the system generates
outputs and can provide some quantification of their quality
reflective construction: the system generates outputs
conforming to a given specification and can provide
some quantification of their degree of satisfaction, and
modify it accordingly.
mere revision: the system receives an instance of the
desired artefact and revises it towards a given goal
determined by its construction
revision to a specification: the system receives an
instance of the desired artefact and a given specification
and revises the instance of the desired artefact towards
the given specification
revision with diagnostic: the system receives an instance
of the desired artefact, revises it towards a given goal
determined by its construction, and can provide some
quantification of the quality of the revised artefact
reflective revision: the system receives an instance of
the desired artefact and a given specification, revises the
instance of the desired artefact towards the given
specification, and can provide some quantification of their
degree of satisfaction of the specification, and modify it
accordingly.
3.2</p>
      </sec>
      <sec id="sec-5-3">
        <title>Summarising the Features of a Creative</title>
      </sec>
      <sec id="sec-5-4">
        <title>Process from a Computational Point of View</title>
        <p>The cognitive models reviewed in section 2.1 show a number
of distinctive features that are relevant for the purpose of the
present paper:
1. the creative process is iterative in nature
2. the creative process is driven by a set of constraints
that restrict the desired outputs in some way; these
constraints may be considered an input to the process
3. a cycle may involve processes of construction and/or
processes of revision of prior results
4. at the end of each cycle a diagnostic procedure is applied
to the result obtained so far
5. part of the diagnostic may involve quantifying degree of
satisfaction of the given constraints
6. subsequent cycles take into account the diagnostic to
attempt to improve the results of subsequent cycles
7. consideration of the diagnostic may take the form of
planning further operations either on the artefact so far
or on the set of constraints
8. the process as a whole includes a stage of meta-level
reasoning which decides among the various available
operational options applicable to the task at hand, such as,
for instance, whether to iterate further or to stop, or,
for a given iteration, whether to construct or to revise,
whether to act upon the artefact itself or upon the set of
constraints, or whether to apply the chosen operation to
the whole element or to specific parts of it
3.3</p>
      </sec>
      <sec id="sec-5-5">
        <title>Integrating the Reviewed Tasks and Features into a Computational Model</title>
        <p>After having analysed both the tasks and the features involved
in the creative process from a computational perspective, we
propose the following three extensions for the refined model
of the computations involved in literary creativity:
to consider the explicit representation of constraints as
part of the draft itself, so that they can be subject to the
same operations as the rest of the draft
to consider a range of operations that includes both
construction and revision
to consider the possibility of focusing system operation
on particular subsets of the draft</p>
        <p>The representation on which the creative process operates
would therefore need to include at least two different parts:
the set of constraints to be used to drive the construction
process and/or to validate any resulting drafts, known as
the brief
the actual draft at each point of the creative process
Both the brief and the draft should be represented in such
a way that different parts of them may be operated upon in
isolation of the rest.</p>
        <p>This representation that includes both a brief and a draft
will be referred to henceforth as the work in progress. Any
references to operations upon the work in progress can refer
to both operations on the draft or on its specification.</p>
        <p>The set of operations to consider would be:
reject: eliminate from the work in progress a particular
item for the next cycle
generate: generate anew a particular item of the work in
progress during the next cycle
revise: modify a particular item of the work in progress
during the next cycle
keep: leave a particular item of the work in progress as
it resulted from the previous cycle</p>
        <p>Based on this terminology, a computational model for the
tasks involved in literary creativity can now be rephrased at
a lower level of detail. The same set of general steps can be
seen, but each one of them now operates over a representation
of the work in progress that includes both a brief and a draft,
and at each stage the four types of operation (reject, generate,
revise or keep) may be applied to any subset of the work in
progress.</p>
        <p>The computational model that we propose may now start
from a hybrid representation of work in progress. Input may
be provided to a creative system either in terms of a brief - a
set of constraints that the output should satisfy – or a partial
sample of the desired artefact, or as a combination of both
modes.</p>
        <p>This initial representation of the work in progress would
undergo a process of reflection. In this initial reflection
process, each of the sections of the work in progress is
considered. If only a brief is available, the brief is marked as to be
retained for the following construction cycle, and the empty
draft is tagged to be generated. If a brief and a partial draft are
available, the partial draft is analysed in the light of the brief.
The result of this analysis will be a diagnostic. Based on this
diagnostic, the available draft is partitioned into sections, and
each of these sections is marked as either to be left as it is
(keep), to be regenerated (generate), to be revised (revise) or
to be rejected (reject). Additionally, if the brief suggests
sections should be added to the partial draft, place holders for
them are added to the partial draft tagged as to be generated.
If only a draft is available, an interpretation process is run on
it to reverse engineer a brief. Based on the resulting brief,
the available draft is processed as above. If neither brief nor
draft are available, the creative system may follow different
procedures, depending on whether a brief or a partial draft is
constructed first.</p>
        <p>Once the initial reflection phase is over, the system would
enter a phase of construction. In spite of the similarities, we
do not refer to this stage as engagement, because engagement
in the sense used by Sharples applies very specifically to a
process of production of new material, and the construction
envisaged here may cover other processes such as revision,
editing, or omisin. During this phase, each of the sections
into which the draft has been partitioned will undergo the
operation for which it has been tagged. The draft will therefore
be edited by the application of the four basic operations
described above. Any sections of the draft that are rejected at
this point are stored in a log of fruitless paths.</p>
        <p>At the end of the construction phase, the system would
enter another phase of reflection. The first aim of this phase
would be to ascertain whether the creative process has been
concluded satisfactorily. This would arise if the draft matches
the brief to perfection.</p>
        <p>If the draft does not match the brief, the system would
proceed with the rest of the reflection phase as described above,
and iterated over another reflection/construction cycle.
During reflection cycles other than the first one, the system may
also consider modifications to the brief. These may arise from
three possible situations. First, if part of the brief has proven
impossible to satisfy during the prior cycle, the system may
consider abandoning it. This would be plausible behaviour
for human creators and should therefore be considered a
possibility for artificial models. It would also constitute a very
useful addition to allow creative system to steer themselves
out of unproductive regions of a conceptual space when the
current brief constrains them to restrict the search so. Second,
if the reverse engineered brief shows positive features that
were not included in the original brief, the system may decide
to include them in the brief for the next iteration. This would
allow such systems to incorporate the concept of serendipity
into their computational models. Third, if the exploration of
the conceptual space during a prior construction phase has
included an excessive number of choices between possible
candidate results, the system may decide to extend the brief
to restrict the search to a subset of the conceptual space in
question. Extensions to the brief should be compatible with
the rest of it, and may take into account information about
prior attempts that have failed.</p>
        <p>Figure 2 depicts the reflective process in the proposed
computational model for the tasks involved in literary creativity,
as compared to the classic version that does not address
feedback (depicted in Figure 1).</p>
        <sec id="sec-5-5-1">
          <title>Invent</title>
          <p>social
constraints
narrative
constraints
Compose
discoursive
constraints
ideas
discourse
judgement
story</p>
        </sec>
        <sec id="sec-5-5-2">
          <title>Tell</title>
          <p>literary
constraints</p>
        </sec>
        <sec id="sec-5-5-3">
          <title>Validate</title>
        </sec>
        <sec id="sec-5-5-4">
          <title>Interpret</title>
          <p>ideas*
narrative
constraints*
The planning process that Flower and Hayes has a dual
purpose of generating ideas – which could correspond to
additions to the ongoing draft – and of generating goals for the
other processes. While the model that Flower and Hayes
propose is not necessarily focused on creative writing, we
consider it to be fundamental for describing narrative
composition from the point of view of feedback. The ability to
generate additions to the ongoing draft would correspond to
Sharples process of engagement, with the slight refinement
that the ideas generated in that case are restricted to the
conceptual space defined by the initial constraints – which would
correspond to our definition of the brief. These processes
are covered by the generate option of our construction phase.
The ability to set goals for other processes as established
during the planning process that Flower and Hayes describe in
their model corresponds to the establishment of constraints
as described by Sharples. These processes are covered in our
model by the part of the reflection stage where modifications
to the brief are considered – in cycles beyond the initial one.</p>
          <p>The translating process described by Flower and Hayes is
described as a process of transforming ideas into text.
According to our definitions, this would correspond to the task
of generating a new instance of a particular section of the draft
according to the corresponding brief, as carried out during a
construction stage.</p>
          <p>Our reflection process combines features of the reviewing
process as described by Flower and Hayes – in as much as
it involves evaluating the material produced so far and
determining which parts of it can stand and which ones need
further operations performed upon them – and the reflection
stage of Sharples’ model in the case of cycles beyond the
initial one – where diagnostic leads not to revision of the draft
but of the brief, which corresponds closely to Sharples’
constraints. These constraints may then affect subsequent
processes of revision but also of further construction or
reconstruction of material already in the draft. The detailed
description of the reflection stage as described by Sharples can
be revisited using the proposed new terminology, which
allows for finer consideration from a computational point of
view of the actual operations involved at each point. The step
that Sharples names reviewing involves a process of
representational redescription – following Karmiloff-Smith – which
clearly goes beyond comparing the results obtained with the
original brief. Sharples specifically describes how the
results obtained are processed to make available for reasoning
within the system knowledge about “the procedures enacted
during composition”. Following Karmiloff-Smith, the raw
data received from the generation processes are interpreted
and internal representations are constructed describing
valuable properties of these data at a more abstract level. This
may take several forms, but a simple solution is to consider
attempts to reverse engineer from the resulting draft a
hypothetical brief that may have lead to it. This might be a
reasonable match for the “explicit representations of specific
constraints” that Sharples describes as likely outcomes of the
process. The task of comparing such a reverse-engineered
brief with the one actually used to drive the construction
process would match Sharples step of contemplation, which
operates on the results of the reviewing step. Sharples includes
in the reflection stage an additional step of planning, where
the results of contemplation lead to the creation of plans or
intentions to guide the next phase of engagement. To fully
capture the subtleties of Sharples analysis we have
considered that the validation stage may result in the application of
the four operations we have described – reject, generate,
revise, keep – to the pair of briefs under consideration: the one
used to generate the draft under revision and the one reverse
engineered from the actual draft obtained. From this process
a new brief will emerge, which can inherit constraints from
the original brief, or delete them.</p>
          <p>The reflection stage as we have described, in as much as it
includes procedures for deciding which operations are to be
carried out next on which parts of the work in progress,
integrates the task of monitoring the creative process to guide
the interaction and alternation between its constituent
subprocesses – as described in Flower and Hayes model. The
description provided in the present paper, given that it starts
from a more fine-grained representation of both the data and
the operations under consideration – allows for a more
detailed and expressive description. This should allow for easier
implementation of instances of creative systems that consider
this type of behaviour.</p>
          <p>With respect to the ICTIVS model, the model proposed in
this paper may be seen as a refinement at a lower level of
detail regarding the types of data involved and the types of
operation carried out on them, but phrased at a higher level
of abstraction with respect to the type of artefact being
considered. The ICTIVS model was designed for the specific
domain of narrative, and because of this it included separate
stages for the ideation of plot or fabula and the composition of
such plots or fabulae into sequential discourses. This would
correspond to having different narrative levels of
representation – fabula and discourse – for the material within the draft,
and contemplating a specific process of conversion from one
to the other. When we abstract away from these features
specific to narrative, we can consider that the stages of
INVENTION and COMPOSITION of the ICTIVS model would
correspond to te construction phase that we have described
in the current model, the INTERPRETATION and
VALIDATION stage would correspond to the reflection stage, and the
TRANSMISSION stage would correspond to the actual action
of publishing or sending the final draft to an audience, which
would correspond to the fulfilling the stopping condition
implicit in our current phrasing of the reflection stage. With
respect to the low level details described above, the task of
reverse engineering a brief from a partial draft would match
closely the processing that is considered during the
interpretation phase of the ICTIVS model. The task of comparing
such a reverse-engineered brief with the one actually used to
drive the construction process would match the ICTIVS stage
of validation.</p>
          <p>The main advantage of this proposal is that two new
sources of additional constraints are now included in the
model of the creative process. First, the reverse-engineered
brief may contain valuable constraints that were not in the
original brief. This would correspond to the occurrence of
serendipity: the constructive process employed leads to
valuable features that were not in the original brief but which
may be noticed during contemplation/interpretation of the
result, and from then on added explicitly to the brief for
subsequent iterations of the process. Second, the model allows
for an explicit process for the generation of new constraints.
This allows for the design of systems that can autonomously
search for their own constraints, which would allow for a
broader range of creative process. With respect to Boden’s
well known taxonomy of creative system [Boden, 2003], as
the constraints being considered define the conceptual space
that is being explored, a system capable of modifying the
constraints that drive it might be capable of achieving
transformational creativity. In this way the proposed models allows for
a more fine grained representation of data and processes that
may lead to the development of more expressive solutions.</p>
          <p>The importance of making the system able to reject
selected parts of its original brief should not be underestimated.
The ability of human creators to depart – sometimes in very
radical ways – from their original intentions in search for
new aesthetics experiences has long been considered a
critical ingredient of creativity of the highest order. It ties in very
closely with the concept of transformational creativity, and
the implicit ability to shift into new paradigms rather than
just explore the old ones. Although all such issues are
currently beyond the state of the art of creative systems, it is
important to enable our computational models to represent
the types of behaviour that may one lead to implementation
of similar behaviours. This would correspond to building
explicitly into our computational models the idea of creativity at
the metalevel [Wiggins, 2006]. The issue of how such
operations might be profitably controlled is beyond the scope of the
present paper and will need to be addressed in further work.
Overall, a large proportion of the success of a creative system
as described in the present proposal will depend on the
implementation of suitable strategies for the partitioning of the
draft into sections requiring the different operations available,
and on the procedures for modifying the brief. These should
be the focus of further work along the lines described in this
paper.
5</p>
        </sec>
      </sec>
    </sec>
    <sec id="sec-6">
      <title>Conclusions</title>
      <p>The processes of literary creativity involve a complex web
of interacting procedures (generation from a brief, evaluating
how a draft matches a given brief, revision of an
intermediate draft to fit a given brief, identifying unexpected valuable
features from a working draft, editing a brief to optimise the
search for creative results,. . . ) and strategies for navigating
between them. Existing cognitive models cover this space
of solutions, but tend to remain at a high level of
abstraction that leaves many of the features relevant for
computation underspecified. The existing computational models of
the writing task that have tried to take the cognitive models
into account have focused on specific features of the process
as their engineering mainstays, without trying to address the
full complexity of the problem as a whole. The present paper
proposes a computational model of the writing task that
considers a broader set of ingredients than had been considered
before, represented at a lower level of granularity in terms of
their computational nature, both in terms of data and in terms
of operations. The resulting model shows a strong potential
for capturing significant phenomena in the field of
creativity not often modelled computationally in the past, such as
revision of drafts, working to a given brief, serendipity, and
transformational creativity.</p>
      <p>A valuable contribution of the proposed model is that it
opens for exploration a significant number of lines of research
to explore how these various phenomena might be addressed
either in terms of working implementations of the proposed
computational model or refinements of its basic formulation.</p>
    </sec>
    <sec id="sec-7">
      <title>Acknowledgments</title>
      <p>This paper has been partially supported by the project WHIM
611560 funded by the European Commission, Framework
Program 7, the ICT theme, and the Future Emerging
Technologies FET program.</p>
    </sec>
  </body>
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