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<article xmlns:xlink="http://www.w3.org/1999/xlink">
  <front>
    <journal-meta />
    <article-meta>
      <title-group>
        <article-title>Understanding the U-Shaped Curve: Central Claims and Applications for AI*</article-title>
      </title-group>
      <contrib-group>
        <contrib contrib-type="author">
          <string-name>B. Briskey</string-name>
          <email>brisbm02@students.ipfw.edu</email>
          <xref ref-type="aff" rid="aff0">0</xref>
        </contrib>
        <contrib contrib-type="author">
          <string-name>M. Greidanus Romaneli</string-name>
          <email>mgreidan@purdue.edu</email>
          <xref ref-type="aff" rid="aff0">0</xref>
        </contrib>
        <contrib contrib-type="author">
          <string-name>D. Hale</string-name>
          <email>haledt01@students.ipfw.edu</email>
          <xref ref-type="aff" rid="aff0">0</xref>
        </contrib>
        <contrib contrib-type="author">
          <string-name>J. Licato</string-name>
          <email>licatoj@ipfw.edu</email>
          <xref ref-type="aff" rid="aff0">0</xref>
        </contrib>
        <aff id="aff0">
          <label>0</label>
          <institution>Indiana University-Purdue University</institution>
          ,
          <addr-line>Fort Wayne</addr-line>
          ,
          <country country="US">USA</country>
        </aff>
      </contrib-group>
      <pub-date>
        <year>2017</year>
      </pub-date>
      <fpage>21</fpage>
      <lpage>28</lpage>
      <abstract>
        <p>Representational Redescription theory as proposed by KarmiloffSmith [1992] investigates the changes in behavioral performance and “level of representation” as children experience new domains of knowledge. In order to introduce the applicability of this theory's propositions to knowledge acquisition in both children and Artificial Intelligence systems, we analyzed the experimental literature in Representational Redescription, as well as in the closely related theory of Neuroconstructivism.</p>
      </abstract>
    </article-meta>
  </front>
  <body>
    <sec id="sec-1">
      <title>INTRODUCTION</title>
      <p>Investigations into how children process information have typically
focused on specific factors, including biological and socio-cultural
constraints, environmental cues, and innate predispositions to
attend to certain stimuli. All of these factors have demonstrated
important influences on how children learn and communicate new
ideas and abilities. However, much of the evidence for these effects
has come from observations and interpretations of behaviors. While
behaviors may be readily observed and interpreted, processes taking
place within the child’s mind that may be influencing behavior may
be quite difficult to identify. One theoretical perspective that
attempts to explain these internal processes, named
“representational redescription theory,” seeks to explain how
children can acquire representations of their external and internal
environments that attain increasing levels of complexity and
flexibility [Karmiloff-Smith, 1992]. Insight into this process may
also have important applications for machine learning and AI, by
facilitating the development of progressively more complex skills
and capacities in intelligent agents. Yet, such applications can only
exist if the concept of ‘representation’ and its change throughout
development is coherent. Unfortunately, work that refers to
representational redescription theory has not been consistent on the
point of what it means for a representation to change.</p>
      <p>We will address the confusion over what a representation is and how
it changes, as predicted by representational redescription theory.
This will be followed by an account of Karmiloff-Smith’s original
operationalizations of key concepts of the developmental curve,
based on her landmark 1992 publication. We will then discuss
subsequent literature on these predictions, while also clarifying the
lack of consensus on how to test representational change
independently from behavioral mastery. Finally, we will present
alternative methods for measuring this change, in specific
neuroconstructivist computational modeling, as well as possible
applications of representational redescription to artificial
intelligence.
2 OVERVIEW OF REPRESENTATIONAL
REDESCRIPTION
Representational redescription theory, originally developed by
Annette Karmiloff-Smith, attempts to explain how a child
represents the external environment within their mind, changes
these representations through continued interaction with the
environment, and eventually reaches a higher degree of both
behavioral mastery and metacognition. Karmiloff-Smith [1992]
divides this process of change into three phases, characterized by
two factors: the level of performance on a task, and the ‘level of
representation[al development],’ an abstract measure whose lack of
a definition is the cause of much confusion. The relation between
levels of performance and representational development form what
Karmiloff-Smith calls a “U-shaped curve” (Figure 1). In phase 1,
performance is high but level of representation is low; the child does
not possess any metacognition about the performance of that
specific behavior, but he or she has learned to associate the behavior
with its context through observation and feedback from the
environment. As the behavior is repeated, they begin to develop a
higher level of representation marked by, for instance,
theorybuilding and generalizations. In phase 2, the level of representation
within a given micro-domain goes up and is associated with lower</p>
      <p>Finally, as the process of representational redescription continues to
phase 3, the child demonstrates more representational flexibility by
not only being able to reflect on and describe the rationales for their
behavior, but also through accounting for exceptions to the
preestablished representations. Thus, the developmental graph of a
specific microdomain shows a linear development of level of
representation, but at the same time a non-linear development of
performance, reaching its lowest level at phase 2. A graph of the
U-Shaped curve, equivalent to the one initially proposed by
Karmiloff-Smith [1992], can be seen in Figure 1. This U-Shaped
curve, originally presented in Karmiloff-Smith [1992] as a
hypothetical model, has room for interpretation. Other authors, such
as Pinker [1995], have referenced this decrease in behavior
performance in other terminology.</p>
      <p>
        Initial support for the change in the level of representation relied
specifically on grammatical development, with changes in
representation marked by the ability to analyze grammatical
elements on a pronoun-noun phrase in French [Karmiloff-Smith,
1979, 1986] and the ability of separating the grammatical elements
of American Sign Language (ASL) [Newport 1981]. The inference
that representational change occurred in these cases stemmed
primarily from the same evidence that suggests a decrease in
behavioral performance.1 In those studies, markers of less accurate
behavior (e.g., breaking down a pronoun into a more complex and
incorrect phase, breaking down a sign in ASL instead of delivering
it fluidly) were indications that children were hyper-aware of the
grammatical elements in their utterances/gestures, to the extent of
prioritizing the acknowledgment of these internal processes over
1 Respectively, the breakdown of the correct utterance “mes voitures” [1st
person + plural possessive “my” + plural “cars”] into incorrect forms in
which grammatical person and number were separated, “les miennes des
2
what was initially correct performance. Late-occurring behavioral
performance errors in both examples constitute a large part of the
evidence for representational change, however, Karmiloff-Smith
further analyzes specific aspects of those mistakes in order to
support the U-shaped curve and representational redescription.
These aspects, as presented in Karmiloff-Smith [1992], were
originally described as accompanying an increase in the level of
complexity of representations, demonstrated by the presentation
over time of abilities not previously available. They include the
abilities to (
        <xref ref-type="bibr" rid="ref1">1</xref>
        ) analyze a procedure/representation into its
meaningful parts, (
        <xref ref-type="bibr" rid="ref2">2</xref>
        ) identify and understand relationships between
elements of a larger whole (e.g., morphemes within words), (3a)
form general theories about a specific procedure or micro-domain,
as well as to (3b) later correctly identify and address exceptions to
such theories, (
        <xref ref-type="bibr" rid="ref4">4</xref>
        ) contrast characteristics or functions of similar
elements (e.g., definite vs. indefinite articles) and (
        <xref ref-type="bibr" rid="ref5">5</xref>
        ) elaborate
verbal explanations of rationales for either correct or incorrect
behavior.
      </p>
      <p>These specific markers of representational change, however, were
not as clearly operationalized as the decrease in behavioral
performance itself in supporting the U-shaped curve, and may be to
blame for some inconsistencies in the research following the
original publication of the theory. The confusion about the meaning
of the U-shaped curve and the ambiguity of representational
redescription’s central claims have led to a variety of incompatible
interpretations. We will now summarize these interpretations.</p>
    </sec>
    <sec id="sec-2">
      <title>3 WORK ON</title>
      <p>REPRESENTATIONAL REDESCRIPTION</p>
    </sec>
    <sec id="sec-3">
      <title>3.1 Language</title>
      <p>One of the domains explored in Karmiloff-Smith [1992] was
language, with an emphasis on semantic and morphosyntactic
development. Critten, Pine, and Steffler [2007] are early
proponents of the application of the theory to other language related
microdomains, such as spelling. In their 2007 study, the lowest level
of representational redescription in children’s spelling development
was operationalized as inflexible behavioral mastery without
conscious access to the knowledge in the microdomain, while the
second and third phases were characterized, respectively, by
overgeneralization errors progressing to less performance errors
without full rule understanding, and finally proficient task
performance with complete comprehension of applicable spelling
rules. The researchers were able to demonstrate a behavioral
developmental curve, in which the decrease in performance was
associated to an over-reliance in specific phonetic or morphological
spelling strategies.</p>
      <p>Expanding on this first study, Critten, Pine, and Messer [2013]
continued to analyze representational and behavioral change within
voitures” [Karmiloff-Smith 1979, 1986] and the breakdown of initially
“holistic” ASL signs into “staccato-like” movements, in which the parts of
the sign were broken down based on its morphological markers.
the microdomains of spelling recognition and production. In the
spelling recognition task, children were asked to choose between
one correct and two incorrect spellings of a list of words, including
regular and irregular verbs, as well as non-verbs. Performance and
ability to justify their choices, as well as why the other alternatives
were incorrect, were taken into account when assigning phases of
representational development to children. While children in the
second-lowest phase had high accuracy in choosing the correctly
spelled option (following a phase of low accuracy), subsequent
phases demonstrated lower accuracy due to the emergence of new
mistakes (e.g., identifying [-ed] as a marker of past-tense in verbs
and rejecting correct spellings of irregular verbs for lacking the
suffix). Finally, in the last phase, children not only regained high
performance, but were also able to explain verbally the rationale for
their choices. This pattern of development, composed of a decrease
in behavioral performance (marked by accuracy) due to the
overregularization of newly identified elements of language (e.g., [-ed]
suffix marking past tense), is in accordance with the original
propositions of the U-Shaped curve and the patterns of behavioral
and representational development proposed by Karmiloff-Smith
[1992].</p>
      <p>In a similar spelling production task, the researchers presented
children with a spelled word or pseudoword, and an assortment of
letter magnets. Children then had to use the letter magnets in order
to transform the previous word into a new word proposed by the
researcher. Performance was measured in terms of their ability to
accurately create the new word and verbally express their
justification for both how they transformed the word and how the
words differed. Successful performance of the task involved
replacing the first letter of the word or pseudoword (always a
consonant) with a different consonant. In this second task,
providing an incorrect explanation coupled with lower task
accuracy was considered by the researchers as a marker of an
intermediate phase, which would correspond to phase 2 of the
Ushaped curve. This spelling production task, unlike other literature
on Representational Redescription and spelling development, did
not directly address morphological development, while the skills
tested were based purely on phonetic development and letter
recognition.</p>
      <p>Critten et al. [2007] and Critten et al. [2013] utilized children’s
verbalizations in order to establish phase distinctions that are not
present in representational redescription theory, creating what
would be a new section of phase 2 of the U-shaped curve,
separating between phonological and morphological
overgeneralizations and errors. This distinction appears to be
specific to the spelling microdomain, and may not necessarily
extend to other developmental microdomains. In proposing the
subdivision, however, the researchers still relied heavily on verbal
explanations, even in the phases in which children are predicted to
not be able to produce them. Evidence based on children’s
explanations, although effective in distinguishing between implicit
(phase 1 in the U-shaped curve, when children are only procedurally
aware of the task) and explicit representations (phase 3 in the
Ushaped curve, when children have a higher level of representation</p>
      <p>MAICS’17, Fort Wayne, Indiana, USA
and are able to verbalize rationales for their behavior), is not
sensitive to the markers of representational change in intermediary
phases.</p>
      <p>Critten, Sheriston, and Man [2016] further examined the
applications of representational redescription theory in the
microdomains of spelling recognition and production. Two groups
of children from three different UK schools, from year 1 and year 2
respectively, performed two separate tasks. Much like Critten, Pine,
and Steffler [2007], children were presented with three words, one
spelled correctly and two incorrectly, and were prompted to give an
explanation as to why their choice was correct and why the other
two choices were not correct. In addition, children were asked to
spell words that had been previously presented, although in a
different order than the child’s previous trial. Critten et al. [2016]
operationalized representations as children’s explicit explanations
about spelling performance using the same evaluation criteria as
Critten, Pine, and Steffler [2007]. The participants were then
grouped together based on an overall level of representational
development, determined by the type of explanation given for their
performance on the tasks. Children in the group corresponding to
phase 2 often made overgeneralization errors and therefore
demonstrated representational inflexibility. The researchers
maintained the subdivisions proposed in previous studies [Critten et
al. 2007; Critten et al. 2013] and provided additional empirical
support to a division between morphological and phonetic errors in
phase 2. This categorization of groups supports the notion of the
Ushaped developmental curve in representational redescription as
children’s explanations became more advanced as well as having
better performance on spelling recognition tasks once their spelling
knowledge became more flexible.</p>
      <p>Lorandi and Karmiloff-Smith [2012], on the other hand, analyzed
children’s morphological knowledge in Brazilian Portuguese. They
did so through recording the spontaneous occurrence of variant
forms of verbs (e.g., overgeneralizations and neologisms
inconsistent with the standard norm of the language), as well as
through a morphological test in which children were given a
nonsense grammatical base (created in accordance with common
word structures in the language) and a semantic context, and were
prompted to produce inflected forms of such words. While
measuring the incidence of errors in these tasks, the researchers
found support for an increase in performance and for children’s
awareness of morphological markers of location, agency, and tense,
among others. Although the results in this study do not make
evident a U-shaped curve of behavioral performance, they support
an increase in level of representation in accordance with the claims
of representational redescription theory (e.g., in children’s ability to
identify and utilize morphological markers in novel productions).
Evidence from microdomains within language, as a whole, indicate
the existence of a U-shaped curve very similar (if not equivalent) to
the one proposed in representational redescription theory. Still, the
simultaneous development of some of these microdomains (such as
phonetics, morphology, and letter recognition in the spelling tasks
described) and the reliance on verbal explanations provide
confounding factors. Thus, these methodologies, although shedding
some light into the relationship between representational
redescription and language development, do not offer generalizable,
agreed-upon insights into this process.</p>
    </sec>
    <sec id="sec-4">
      <title>3.2 Mathematics</title>
      <p>While representational redescription is argued to be
domainspecific — that is, representations in each micro-domain undergo
the developmental process independently — the investigations
seeking to support or refute the theory’s claims vary greatly in
terms of domains of knowledge analyzed. One of the fields of
experimental research mentioned by Karmiloff-Smith [1992] was
arithmetic. Voutsina [2012] examined the presence of markers of
representational redescription through testing children’s ability to
identify number pairs, i.e. what numbers can be added together to
obtain a specified number. A qualitative analysis of ten 5-6 year
old children’s strategies in finding all pairs of numbers revealed
that children’s explanations of behavioral strategies changed over
the course of the study, based on a set number of phases
determined by the researchers. Children in the first phase were able
to distinctly view the procedures for solving each step; this first
step involved children only trying to solve what number pairs
made up the number bond without regard to linking the different
number pairs together. Later, in the second and third phases,
children were able to manipulate and link different aspects of
knowledge. After observing how they solved the problem, children
developed a strategy for organizing number pairs for number
bonds. For example, for the number bond “9”, children would
replace [0+9] for [9+0], in a strategy called swapping, rather than
randomly organizing number bonds, such as [2+7] and then [4+5].
Thus, Voutsina [2012] provides evidence for a constant increase
in level of redescription, marked by the emergence of new abilities
and strategies from phase to phase. Furthermore, throughout the
study, strategies used by the children (such as the ordering
strategy) resulted in constant behavioral performance. Considering
also that even in the first level of representation, described by the
researchers, there were already signs of a higher level of
redescription; Voutsina [2012] provides evidence for what appears
to be the upwards slope of both behavioral performance and level
of redescription. It does not, however, provide evidence
supporting or refuting the decrease in performance characteristic
of the U-shaped curve, as there was no operationalization for
verifying the process of spontaneous redescription of knowledge.
Likewise, Simpson and Stehlikova [2006] examined
representational redescription in the domain of Algebra. Rather
than with children, this study observed a college student’s
development across a span of three-years in a case study. Initially,
the participant followed strict procedures in order to solve the
problems, such as solely adding up the numbers in the problems.
The “second shift of attention,” or the first explicit level, was
operationalized as using the knowledge gained from the familiar
procedure towards similar problems that would also use a similar
procedure. During the study, as the participant gained a more
in4
depth understanding of the representation, she made errors;
eventually the participant realized the errors and corrected them. As
time went on, she verbalized the relationships between some of the
numbers before moving to the last phase of representational
redescription where she utilized her knowledge about the problems
and procedures the professor gave to similar, extra problems and the
operations needed to solve them. This participant's performance
during the study supports the existence of the U-shaped
developmental curve in representational redescription theory.
Despite this support, there was no operationalization for verifying
the process of spontaneous redescription of knowledge; Simpson
and Stehlikova [2006] acknowledged that there was no spontaneous
redescription of knowledge, as the participant did not suddenly gain
an insight to utilize a specific abstract algebra strategy
(zsubtraction) even though she realized and corrected her errors. Even
though there was no spontaneous redescription of knowledge,
support for the U-shaped developmental curve in Simpson and
Stehlikova [2006] was found as the participant’s performance at
first decreased before increasing.</p>
    </sec>
    <sec id="sec-5">
      <title>3.3 Drawing</title>
      <p>The domain of drawing involves representations; these
representations can be modified and applied to various drawing
microdomains. In Picard and Vinter [2006], it was hypothesized
that exposure to a model would increase performance in an
associated task. Children were tasked with drawing pictures with
components that either had no separation or separation by two parts
or multiple separations. It was discovered that breaking down
knowledge helped change the representation from implicit to
explicit; through this decomposition process redescription could
occur. During decomposition, children made new knowledge
connections such as being able to identity and draw the different
parts of the drawing, indicative of knowledge being redescribed.
Similarly to Picard and Vinter [2006], Hollis and Low [2005]
investigated representational redescription in the drawing
microdomain. The purpose was to investigate environmental
constraints that impacted the flexibility of representational
redescription in the drawing domain. The study had 315 children,
whose ages ranged from 6 to 9 years old. The participants were
tasked with drawing pictures of a typical house and person before
being tasked with drawing a picture of a “pretend person.”
Afterwards, researchers asked the participants to talk about their
“pretend person” and later put the children into either the distraction
condition, draw alone condition, or the explanation about why this
is a “pretend person” condition.</p>
      <p>The participants were tested a total of four times. The results from
Hollis and Low [2005] support representational redescription. It
was observed that children aged 6-7 were at the beginning phase of
redescription; their procedures were inflexible. This changed over
time, however, when their knowledge became more flexible after
exposure to the explanation condition; this condition was associated
with a greater rate drawing modification during the middle of the
drawing process. This change in knowledge, from inflexible
performance with few mistakes, to flexible performance with many
errors, is in support of the U-shaped developmental curve.</p>
    </sec>
    <sec id="sec-6">
      <title>3.4 Block Balancing Tasks</title>
      <p>Similar to the language domain, representational redescription has
been widely studied in the block balancing microdomain, where
children are tasked with balancing blocks on a beam. Messer, Pine,
and Butler [2008] hypothesized that representations are similar in a
domain, even if the tasks vary. Children in an equivalent of phase
two of representational development tended to have lower
performance than children at later representational levels, even
though they used consistent strategies to try to solve the block
balancing task. Although the children utilized the same strategies in
order to solve the block balancing task, the children who had not yet
redescribed their knowledge had more errors while solving the task,
in comparison to children who redescribed some of the knowledge.
This is in contrast to children at the first phase who could not
explain why their behavior on a task but still had high behavioral
performance. This change in knowledge, from inflexible
performance with few mistakes, to flexible performance with many
errors, along with the decrease in performance for children at the
abstraction level, supports the U-shaped developmental curve.
Representational change was operationalized as a difference in
performance in tasks. Cheung and Wong [2011] hypothesized that
participants would be unaware that they transferred the strategy of
a geometric-center theory for balancing the blocks to different tasks.
Behavioral performance was operationalized by how many times
children successfully placed blocks in the middle of the beam, in
the middle before moving them, and only in the center area of the
beam for each block trial. Eight of the twelve participants utilized
geometric-center theory across the task; this theory states that
children believe that all objects can be balanced at the center.
Despite utilizing this strategy, children were unaware of this
knowledge, supporting the hypothesis; they tried to complete the
task but were unable to explain what their strategy utilized.
Although the U-shaped pattern did not appear in the study, Cheung
and Wong [2011] argued that the absence of the U-shaped curve
does not discredit the representational redescription model, as it is
not the main premise behind representational redescription. Other
researchers, however, have utilized this absence of a U-Shaped
curve in their data as a basis for refuting Representational
Redescription theory [Krist, Horz, and Schonfeld, 2005].
Krist, Horz, and Schonfeld [2005] disputed representational
redescription in the block balancing task due to the absence of the
U-shaped developmental curve. The U-shaped curve was
operationally defined as children utilizing the geometric-centric
theory during the block balancing task. The study tasked sixty five
children, between 4 and 8 years old, with balancing wooden blocks,
evenly and unevenly weighted, on a beam. In order to not influence
the theories that the children made while completing the task,
researchers did not prompt children with questions such as if some
blocks are “unbalanceable.” Rather, the researchers asked the
children why/how blocks can be balanced. It was predicted that</p>
      <p>MAICS’17, Fort Wayne, Indiana, USA
success with the task would follow the U-shaped curve with the
unevenly weighted blocks: a decrease in performance subsequently
followed by an increase due to the redescription of block knowledge
from correct block readjustments. This change in performance
would be indicative of the children’s representational change from
the first explicit level (E1) to the later levels (E2 and E3). Success
with evenly weighted blocks, however, was predicted to either stay
the same or increase with children’s age.</p>
      <p>Results in Krist et al. [2005], however, showed no support for the
U-shaped curve. While performance success improved with evenly
weighted blocks, in unevenly weighted blocks performance success
decreased along with children’s correct block rearrangements. Kris
et al. [2005] explained this lack of evidence due to differences in
the methodology utilized in Karmiloff-Smith’s On Modularity;
Krist et al. [2005] had more participants, a standardized system to
measure children’s performance, and did not prompt the
participants to make predictions but rather why/how blocks can be
balanced in contrast to the original study. Additionally, these results
differed due to the fact that the theory of representational
redescription has not made clear an operationalization for verifying
the process of spontaneous redescription of knowledge, which
resulted in these studies using diverging, and often conflicting,
methodologies. Despite criticisms and lacking evidence for the
Ushaped curve, Krist et al. [2005] advocated for finding domains
representational redescription can occur in, rather than throwing out
representational redescription theory. Although skeptical, Krist et
al. [2005] acknowledged a possible connection between
representational redescription and “modern connectionism with
developmental neuropsychology,” or neuroconstructivism.</p>
    </sec>
    <sec id="sec-7">
      <title>3.5 Neuroconstructivism</title>
      <p>Achieving a consensus regarding what constitutes a
“representation,” along with how such a representation might adapt
or change, appears to be a critical problem when testing
representational redescription. In the studies previously described,
behavior has been linked with encoded information states, i.e.
representations, effectively associating changes in behavior with
changes of these representations. In addition, verbal reports of one’s
understanding can lead to alterations of this understanding, and only
the representations that can be verbalized may be accounted for with
this methodology. So far there has been no direct way to measure
representational change within human participants. However,
Karmiloff-Smith [1992] mentions that computational modeling
may provide important insights into specific brain processes that
cannot be measured through other experimental means.
The theory of neuroconstructivism may provide some assistance
with quantifying representations. A central assertion of this theory
is that cognition affects the development of the brain, and the
current state of the brain constrains cognitive development
[Mareschal, et al. 2007; Polk &amp; Farah 1998; Sirois, et al. 2008;
Westermann, et al. 2007]. It is because of this interdependent
relationship that any theory regarding cognitive function should be
informed by underlying biological activity without reducing all
cognition to simply biological function. By investigating neural
function, through the use of computational modeling, and the
relationships between levels of description, such as behavior in
relation to the state of a neural model, it might be possible to
observe representational change in a more direct manner.
Various computational models have been developed with the intent
to simulate neural function in a way that mimics observed human
behavior, and these models might then provide insights into human
neural functioning. One such model is used in Westermann [1998]
to simulate brain activity in a way that closely approximates human
learning of English past tense verbs. The model consists of a large
number of nodes acting as an idealized version of a neural network.
Nodes are assembled into an input layer, responding to a specific
stimulus, a hidden layer that modifies the outputs of the model, and
an output layer. In the neuroconstructivist model, the number of
nodes present in the model is modified, in addition to the weights of
the connections between nodes. In this way, the model modifies its
structure by constantly evaluating each node in the hidden layer, and
each of these nodes are replaced if they are found to be contributing
to a large amount of errors according to certain algorithms operating
within the system. Because each node in the hidden layer only
responds to certain inputs, each node has a certain “receptive” field
for which the node will activate, and modification of the hidden
layer alters these fields. In this way, the model learns how to
reproduce a large amount of past tense verbs when provided with
the present tense version, and this is accomplished by changing the
structure of the network in order to more effectively represent
information.</p>
      <p>After exposing the model to many different verbs, both regular and
irregular, different trends about the model and its performance can
be observed. In Westermann [1998], it was discovered that the
model, which starts with only two nodes in the hidden layer,
develops receptive fields that may overlap, implying that some
nodes may respond to the same input as other nodes; however, there
6
may be many inputs that are exclusive to either node. The hidden
layer is described as a type of “memory” by the author, which
responds to the identity of certain verbs rather than just the
structural qualities of the word.</p>
      <p>Additionally, Westermann and Ruh [2012] continued
experimentation with this model and past tense acquisition,
discovering that as the model was exposed to more verbs, the nodes
in the hidden layer became more specialized to either regular or
irregular verb forms. In addition, this model demonstrated U-shaped
performance, i.e. failing to reproduce verbs that had been produced
accurately at an earlier time. Model performance was then
compared to results of previous studies involving human
participants completing similar tasks, and a significant correlation
was reported [Westermann &amp; Ruh 2012].</p>
      <p>The specific properties of this model seem to have implications for
understanding cognitive development within humans. First, the
late-occurring errors observed in both the model and human
participants seem to indicate that there are similar processes taking
place in both contexts. The hidden layer is also of interest in that the
structural change to the model may indicate a change in how the
model represents the information presented to it. In this way, the
number of hidden units, the degree of specialization among these
units, and the receptive field that each node possesses all seem to be
direct indications of representational change and development at the
level of a neural network. If this is the case, then there appears to be
evidence for an increase in the complexity of representations across
developmental time in the form of increased nodes in the hidden
layer of the model (see Figure 2 for a visual depiction of this
concept, as originally presented by Karmiloff-Smith which allows
room for interpretation). The hidden layer also starts with very
broad receptive fields (two nodes accounting for all inputs) that
become increasingly complex in order to compensate for ineffective
performance of the current network. This seems to mirror
representational redescription on the cognitive level in response to
exceptions to current theories.</p>
      <p>By developing a computational model with similar behavioral
qualities as human participants, inferences into how the brain and
mind might be developing may be formed. However, this specific
neuroconstructivist model only operates within the domain of
English past-tense verb acquisition. In order to provide further
insights into the other domains previously mentioned in this paper,
it would be necessary to construct models that can operate within
these domains. It may also be the case that such modeling can be
applied to other fields of study, particularly those that utilize more
advanced neural network models, such as artificial intelligence.</p>
    </sec>
    <sec id="sec-8">
      <title>4 APPLICATIONS TO ARTIFICIAL INTELLIGENCE</title>
      <p>Given the current popularity of brain-inspired computational
representations (e.g., deep neural networks and deep reinforcement
learners), knowledge about how representations develop and
change in human brains is more relevant than ever. Taken together,
the neuroconstructivist model and representational redescription
specialized, and each node gains a receptive field, indicative of
theory offer a unique approach for the design and study of artificial
representational change. Thus, the theory of neuroconstructivism
intelligence. As demonstrated in Westermann and Ruh’s [2012]
fills in the gaps in the central claims of representational
model, representational change may provide a way for a machine to
redescription, as well as decreasing the confusion over what a
develop effective representations when presented with novel
representation is.
stimuli. This may provide a significant advantage over fixed
programming, in that adaptation to open environments would
become possible. By changing how information is stored,
artificially intelligent agents may become better able to adapt to
their environment, leading to more efficient automation with
broader, more human-like capabilities.</p>
      <p>In this paper, we have surveyed the literature on representational
redescription theory and the closely related neuroconstructivist
theory, finding that they both (when properly interpreted) predict
the existence of a U-shaped curve in the development of mental
representations. We claim that this striking fact has implications for
AI research, especially as the field continues to be dominated by
Conversely, artificial intelligence research might also provide
increasingly massive neural-like networks. Namely, computational
insights into the representational redescription theory that the
representations that claim to be realistic models of the mind must,
current data with human participants has not yet been able to
at a
minimum, be able to show how representations and
address. In the U-shaped curve, for instance, one of the main
performance match the predictions set out by representational
markers of the increase in the level of representation in phase 2 is a
redescription theory. In future work, we hope to expand on these
decrease in developmental performance. While this decrease in
implications for AI research.
performance is adequate behavioral evidence for the curve, it does
not sufficiently support the claim of representational change.
Utilizing AI models in testing the existence of the U-shaped curve
would allow for a clear, measurable, and observable separation
between performance and the representations that facilitate
behavior.</p>
      <p>Other critical aspects must be considered when using artificially
intelligent agents to observe representational change
within
different domains. As mentioned above, the neuroconstructivist
model is only designed for learning past-tense forms of English
verbs. Using neural models that can alter connection weights in
addition to the structure of the network itself in the context of agents
that can manipulate physical objects may assist in explaining the
differences observed between studies investigating children’s
performance on the block balancing task. In fact, many other
domains and tasks may be investigated in this manner.
5</p>
    </sec>
    <sec id="sec-9">
      <title>CONCLUSIONS</title>
      <p>The confusion on the meaning of the three phases and the ambiguity
of representational redescription’s central claims have led to a
variety of incompatible interpretations, particularly with respect to
the correct meaning and use of the U-shaped curve. There is a lack
of generalized consensus among previous studies about what
constitutes representational change in the context of this theory and
finding means to test for this change that do not rely on the
behavioral component of the U-shaped curve. The majority of prior
studies did not operationalize representational change effectively as
they based representational change solely off of observable
behaviors. In this paper, we hoped to decrease the confusion about
representation in Representational Redescription Theory. By
examining neuroconstructivism in relation to representational
redescription, representational change can be quantified without
dependence on behavior as this theory states that cognition affects
brain development; as knowledge becomes redescribed, the number
of nodes increase, the nodes in the hidden layer become more</p>
    </sec>
  </body>
  <back>
    <ref-list>
      <ref id="ref1">
        <mixed-citation>
          [1]
          <string-name>
            <surname>Cheung</surname>
            ,
            <given-names>C.</given-names>
          </string-name>
          , &amp;
          <string-name>
            <surname>Wong</surname>
            ,
            <given-names>W.</given-names>
          </string-name>
          (
          <year>2011</year>
          ).
          <article-title>Understanding conceptual development along the implicit-explicit dimension: Looking through the lens of the representational redescription model</article-title>
          .
          <source>Child Development</source>
          ,
          <volume>82</volume>
          (
          <issue>6</issue>
          ),
          <fpage>2037</fpage>
          -
          <lpage>2052</lpage>
          . doi:
          <volume>10</volume>
          .1111/j.1467-
          <fpage>8624</fpage>
          .
          <year>2011</year>
          .
          <volume>01657</volume>
          .x
        </mixed-citation>
      </ref>
      <ref id="ref2">
        <mixed-citation>
          [2]
          <string-name>
            <surname>Critten</surname>
            ,
            <given-names>S.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Sheriston</surname>
            ,
            <given-names>L.</given-names>
          </string-name>
          , &amp;
          <string-name>
            <surname>Mann</surname>
            ,
            <given-names>F.</given-names>
          </string-name>
          (
          <year>2016</year>
          ).
          <article-title>Young children's spelling representations and spelling strategies</article-title>
          .
          <source>Learning &amp;amp; Instruction</source>
          ,
          <fpage>4634</fpage>
          -
          <lpage>44</lpage>
          .
        </mixed-citation>
      </ref>
      <ref id="ref3">
        <mixed-citation>
          [3]
          <string-name>
            <surname>Critten</surname>
            ,
            <given-names>S.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Pine</surname>
            ,
            <given-names>K. J.</given-names>
          </string-name>
          , &amp;
          <string-name>
            <surname>Messer</surname>
            ,
            <given-names>D. J.</given-names>
          </string-name>
          (
          <year>2013</year>
          ).
          <article-title>Revealing children's implicit spelling representations</article-title>
          .
          <source>British Journal Of Developmental Psychology</source>
          ,
          <volume>31</volume>
          (
          <issue>2</issue>
          ),
          <fpage>198</fpage>
          -
          <lpage>211</lpage>
          . doi:
          <volume>10</volume>
          .1111/bjdp.12000
        </mixed-citation>
      </ref>
      <ref id="ref4">
        <mixed-citation>
          [4]
          <string-name>
            <surname>Critten</surname>
            ,
            <given-names>S.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Pine</surname>
            ,
            <given-names>K.</given-names>
          </string-name>
          , &amp;
          <string-name>
            <surname>Steffler</surname>
            ,
            <given-names>D.</given-names>
          </string-name>
          (
          <year>2007</year>
          ).
          <article-title>Spelling development in young children: A case of representational redescription?</article-title>
          .
          <source>Journal Of Educational Psychology</source>
          ,
          <volume>99</volume>
          (
          <issue>1</issue>
          ),
          <fpage>207</fpage>
          -
          <lpage>220</lpage>
          . doi:
          <volume>10</volume>
          .1037/
          <fpage>0022</fpage>
          -
          <lpage>0663</lpage>
          .
          <year>99</year>
          .1.
          <fpage>207</fpage>
        </mixed-citation>
      </ref>
      <ref id="ref5">
        <mixed-citation>
          [5]
          <string-name>
            <surname>Hollis</surname>
            ,
            <given-names>S.</given-names>
          </string-name>
          , &amp;
          <string-name>
            <surname>Low</surname>
            ,
            <given-names>J.</given-names>
          </string-name>
          (
          <year>2005</year>
          ).
          <article-title>Karmiloff-Smith's RRM distinction between adjunctions and redescriptions: It's about time (and children's drawings)</article-title>
          .
          <source>British Journal Of Developmental Psychology</source>
          ,
          <volume>23</volume>
          (
          <issue>4</issue>
          ),
          <fpage>623</fpage>
          -
          <lpage>644</lpage>
          . doi:
          <volume>10</volume>
          .1348/026151005X35390
        </mixed-citation>
      </ref>
      <ref id="ref6">
        <mixed-citation>
          [6]
          <string-name>
            <surname>Krist</surname>
            ,
            <given-names>H.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Horz</surname>
            ,
            <given-names>H.</given-names>
          </string-name>
          , &amp;
          <string-name>
            <surname>Schönfeld</surname>
            ,
            <given-names>T.</given-names>
          </string-name>
          (
          <year>2005</year>
          ).
          <article-title>Children's block balancing revisited: No evidence for representational redescription</article-title>
          .
          <source>Swiss Journal</source>
          Of Psychology / Schweizerische Zeitschrift Für Psychologie / Revue Suisse De Psychologie,
          <volume>64</volume>
          (
          <issue>3</issue>
          ),
          <fpage>183</fpage>
          -
          <lpage>193</lpage>
          . doi:
          <volume>10</volume>
          .1024/
          <fpage>1421</fpage>
          -
          <lpage>0185</lpage>
          .
          <year>64</year>
          .3.
          <fpage>183</fpage>
        </mixed-citation>
      </ref>
      <ref id="ref7">
        <mixed-citation>
          [7]
          <string-name>
            <surname>Lorandi</surname>
            ,
            <given-names>A.</given-names>
          </string-name>
          , &amp;
          <string-name>
            <surname>Karmiloff-Smith</surname>
            ,
            <given-names>A.</given-names>
          </string-name>
          (
          <year>2012</year>
          ).
          <article-title>From sensitivity to awareness: morphological knowledge and the Representational Redescription model</article-title>
          . Letras De Hoje,
          <volume>47</volume>
          (
          <issue>1</issue>
          ),
          <fpage>6</fpage>
          -
          <lpage>16</lpage>
          .
        </mixed-citation>
      </ref>
      <ref id="ref8">
        <mixed-citation>
          [8]
          <string-name>
            <surname>Mareschal</surname>
            ,
            <given-names>D.</given-names>
          </string-name>
          , Johnson,
          <string-name>
            <given-names>M. H.</given-names>
            ,
            <surname>Sirois</surname>
          </string-name>
          ,
          <string-name>
            <given-names>S.</given-names>
            ,
            <surname>Spratling</surname>
          </string-name>
          ,
          <string-name>
            <surname>M. W.</surname>
          </string-name>
          , Thomas,
          <string-name>
            <given-names>M.S.C.</given-names>
            , &amp;
            <surname>Westermann</surname>
          </string-name>
          ,
          <string-name>
            <surname>G.</surname>
          </string-name>
          (
          <year>2007</year>
          ).
          <article-title>Neuroconstructivism: How the brain constructs cognition</article-title>
          . Oxford, New York: Oxford University Press.
        </mixed-citation>
      </ref>
      <ref id="ref9">
        <mixed-citation>
          [9]
          <string-name>
            <surname>Messer</surname>
            ,
            <given-names>D. J.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Pine</surname>
            ,
            <given-names>K. J.</given-names>
          </string-name>
          , &amp;
          <string-name>
            <surname>Butler</surname>
            ,
            <given-names>C.</given-names>
          </string-name>
          (
          <year>2008</year>
          ).
          <article-title>Children's Behaviour and Cognitions across Different Balance Tasks</article-title>
          .
          <source>Learning And Instruction</source>
          ,
          <volume>18</volume>
          (
          <issue>1</issue>
          ),
          <fpage>42</fpage>
          -
          <lpage>53</lpage>
        </mixed-citation>
      </ref>
      <ref id="ref10">
        <mixed-citation>
          [10]
          <string-name>
            <surname>Patkowski</surname>
            ,
            <given-names>M.</given-names>
          </string-name>
          (
          <year>2013</year>
          ).
          <article-title>The critical period and parameter setting in five cases of delayed L1 acquisition</article-title>
          .
          <source>EUROSLA Yearbook</source>
          ,
          <volume>13</volume>
          ,
          <fpage>1</fpage>
          -
          <lpage>21</lpage>
          . https://doi.org/10.1075/eurosla.13.03pat
        </mixed-citation>
      </ref>
      <ref id="ref11">
        <mixed-citation>
          [11]
          <string-name>
            <surname>Picard</surname>
            ,
            <given-names>D.</given-names>
          </string-name>
          , &amp;
          <string-name>
            <surname>Vinter</surname>
            ,
            <given-names>A.</given-names>
          </string-name>
          (
          <year>2006</year>
          ).
          <article-title>Decomposing and connecting object representations in 5- to 9-year-old children's drawing behaviour</article-title>
          .
          <source>British Journal Of Developmental Psychology</source>
          ,
          <volume>24</volume>
          (
          <issue>3</issue>
          ),
          <fpage>529</fpage>
          -
          <lpage>545</lpage>
          . doi:
          <volume>10</volume>
          .1348/026151005X49836
        </mixed-citation>
      </ref>
      <ref id="ref12">
        <mixed-citation>
          [12]
          <string-name>
            <surname>Pinker</surname>
            ,
            <given-names>S.</given-names>
          </string-name>
          (
          <year>1995</year>
          ).
          <article-title>The language instinct: The new science of language and mind</article-title>
          (Vol.
          <volume>7529</volume>
          ). Penguin UK.
        </mixed-citation>
      </ref>
      <ref id="ref13">
        <mixed-citation>
          [13]
          <string-name>
            <surname>Polk</surname>
            ,
            <given-names>T. A.</given-names>
          </string-name>
          , &amp;
          <string-name>
            <surname>Farah</surname>
            ,
            <given-names>M. J.</given-names>
          </string-name>
          (
          <year>1998</year>
          ).
          <article-title>The neural development and organization of letter recognition: Evidence from functional neuroimaging, computational modeling, and behavioral studies</article-title>
          .
          <source>Proceedings of the National Academy of Sciences</source>
          ,
          <volume>95</volume>
          (
          <issue>3</issue>
          ),
          <fpage>847</fpage>
          -
          <lpage>852</lpage>
          .
        </mixed-citation>
      </ref>
      <ref id="ref14">
        <mixed-citation>
          [14]
          <string-name>
            <surname>Simpson</surname>
            ,
            <given-names>A.</given-names>
          </string-name>
          , &amp;
          <string-name>
            <surname>Stehlíková</surname>
            ,
            <given-names>N.</given-names>
          </string-name>
          (
          <year>2006</year>
          ).
          <article-title>Apprehending Mathematical Structure: A Case Study of Coming to Understand a Commutative Ring</article-title>
          .
          <source>Educational Studies In Mathematics</source>
          ,
          <volume>61</volume>
          (
          <issue>3</issue>
          ),
          <fpage>347</fpage>
          -
          <lpage>371</lpage>
          .
        </mixed-citation>
      </ref>
      <ref id="ref15">
        <mixed-citation>
          [15]
          <string-name>
            <surname>Sirois</surname>
            ,
            <given-names>S.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Spratling</surname>
            ,
            <given-names>M.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Thomas</surname>
            ,
            <given-names>M. S. C.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Westermann</surname>
            ,
            <given-names>G.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Mareschal</surname>
            ,
            <given-names>D.</given-names>
          </string-name>
          , &amp;
          <string-name>
            <surname>Johnson</surname>
            ,
            <given-names>M. H.</given-names>
          </string-name>
          (
          <year>2008</year>
          ).
          <article-title>Précis of Neuroconstructivism: How the Brain Constructs Cognition</article-title>
          .
          <source>Behavioral and Brain Sciences</source>
          ,
          <volume>31</volume>
          (
          <issue>3</issue>
          ). https://doi.org/10.1017/S0140525X0800407X
        </mixed-citation>
      </ref>
      <ref id="ref16">
        <mixed-citation>
          [16]
          <string-name>
            <surname>Voutsina</surname>
            ,
            <given-names>C.</given-names>
          </string-name>
          (
          <year>2012</year>
          ).
          <article-title>Procedural and conceptual changes in young children's problem solving</article-title>
          .
          <source>Educational Studies In Mathematics</source>
          ,
          <volume>79</volume>
          (
          <issue>2</issue>
          ),
          <fpage>193</fpage>
          -
          <lpage>214</lpage>
          . doi:
          <volume>10</volume>
          .1007/s10649-011-9334-1
        </mixed-citation>
      </ref>
      <ref id="ref17">
        <mixed-citation>
          [17]
          <string-name>
            <surname>Westermann</surname>
            ,
            <given-names>G.</given-names>
          </string-name>
          (
          <year>1998</year>
          ).
          <article-title>Emergent modularity and U-shaped learning in a Constructivist neural network learning the English past tense</article-title>
          .
          <source>Proceedings of the 20th Annual Conference of the Cognitive Science Society</source>
          ,
          <year>1998</year>
          .
        </mixed-citation>
      </ref>
      <ref id="ref18">
        <mixed-citation>
          [18]
          <string-name>
            <surname>Westermann</surname>
            ,
            <given-names>G.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Mareschal</surname>
            ,
            <given-names>D.</given-names>
          </string-name>
          , Johnson,
          <string-name>
            <given-names>M. H.</given-names>
            ,
            <surname>Sirois</surname>
          </string-name>
          ,
          <string-name>
            <given-names>S.</given-names>
            ,
            <surname>Spratling</surname>
          </string-name>
          ,
          <string-name>
            <given-names>M. W.</given-names>
            , &amp;
            <surname>Thomas</surname>
          </string-name>
          ,
          <string-name>
            <surname>M. S. C.</surname>
          </string-name>
          (
          <year>2007</year>
          ).
          <source>Neuroconstructivism. Developmental Science</source>
          ,
          <volume>10</volume>
          (
          <issue>1</issue>
          ),
          <fpage>75</fpage>
          -
          <lpage>83</lpage>
          . https://doi.org/10.1111/j.1467-
          <fpage>7687</fpage>
          .
          <year>2007</year>
          .
          <volume>00567</volume>
          .x
        </mixed-citation>
      </ref>
      <ref id="ref19">
        <mixed-citation>
          [19]
          <string-name>
            <surname>Westermann</surname>
            ,
            <given-names>G.</given-names>
          </string-name>
          , &amp;
          <string-name>
            <surname>Ruh</surname>
            ,
            <given-names>N.</given-names>
          </string-name>
          (
          <year>2012</year>
          ).
          <article-title>A Neuroconstructivist Model of Past Tense Development and Processing</article-title>
          .
          <source>Psychological Review</source>
          ,
          <volume>119</volume>
          (
          <issue>3</issue>
          ),
          <fpage>649</fpage>
          -
          <lpage>667</lpage>
          . https://doi.org/10.1037/a0028258
        </mixed-citation>
      </ref>
      <ref id="ref20">
        <mixed-citation>
          [20]
          <string-name>
            <surname>Xie</surname>
            ,
            <given-names>K.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Fox</surname>
            ,
            <given-names>G. E.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Liu</surname>
            ,
            <given-names>J.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Lyu</surname>
            ,
            <given-names>C.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Lee</surname>
            ,
            <given-names>J. C.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Kuang</surname>
          </string-name>
          , H., …
          <string-name>
            <surname>Tsien</surname>
            ,
            <given-names>J. Z.</given-names>
          </string-name>
          (
          <year>2016</year>
          ).
          <article-title>Brain Computation Is Organized via Power-of-Two-Based Permutation Logic</article-title>
          .
          <source>Frontiers in Systems Neuroscience</source>
          ,
          <volume>10</volume>
          . https://doi.org/10.3389/fnsys.
          <year>2016</year>
          .00095
        </mixed-citation>
      </ref>
    </ref-list>
  </back>
</article>