Investigations in Universal Grammar: A Guide to Experiments on the Acquisition of Syntax and Semantics (Language, Speech, and Communication)

342 Pages·2003·6.49 MB·English

by  Stephen Crain

Acknowledgments
(cid:0)
The experimentalm ethods and the model of the languagea pparatusd escribedi n this
book were developed over many years, so there are many people to thank. We ex-
tend our gratitude first to students and collaborators at the University of Con-
necticut: Sergey A vrutin, Eva Bar-Shalom, Carole Boster, Paul Gorrell, Anne Halbert,
Paul Macaruso, Kazumi Matsuoka, Yoichi Miyamoto, Weijia Ni, Carrie O'Leary, Jaya
Sarma, Ana Varela, and especially Cecile McKee, Mineharu Nakayama, and Laura
Conway. We also thank more recent students and other collaborators at the Uni-
versity of Maryland at College Park: Peggy Antoinesse, SharonA rmon-Lotem, John
Drury, Julien Musolino, Susan Powers, Fred Savares,e Caro Struijke, Spyridoula
Varlokosta, and especiallyL ena Gavruseva.
Weare grateful to many colleagues, whose advice we frequently sought and
whose encouragementw e always received: Gennaro Chierchia, Peter Culicover, Janet
Fodor, Teresa Guasti, Henry Hamburger, Norbert Hornstein, Howard Lasnik, Al
Liberman, David Lightfoot, Diane Lillo-Martin, Don Shankweile,r Juan Uriagereka,
Amy Weinberg, Jurgen Weissenborn, and Edwin Williams. We profited most of all
from extensive discussionsw ith Ken Wexler, who deservesm uch of the credit for
developing the Modularity Matching Model.
The true heroes of the piece are the administrators, teachers, and children at the
day care centersw here we conducted our research. We want to mention in particular
the Director, Charlotte Madison, and two of our longtime friends, the teachersS ue
Spencera nd Margaret Lima, at the Child Development Laboratoriesa t the University
of Connecticut. Among our new family at the Center for Young Children at the
University of Maryland at College Park, we want to give special recognition to the
Director, Fran Favretto, and to the Director of Researc,h Anne Daniel.
For helping to take the photos, we are indebted to Julien Musolino. An extra-
specialt hanks goes to Laura Conway for drawing many of the illustrations.
There are four people we cannot thank enough, for providing insightful comments
on the entire manuscript: Teresa Guasti, William Snyder, Brian Byrne, and Roger
Wales.
We end by expressing our heartfelt appreciation to our parents, Garth and Judith
Thornton and Bill and Kay Crain, as well as to Stephen's sons, Willis and Austin.
Most of this book was written in the year before and the year after the birth of our
own LAD, Aurora Luisa Thornton Crain. Not only is Aurora free of responsibility for
any mistakesc ontained herein- she has made the past two years the happiest of our
Ii ves.

Chapter 1
In traduction
This book is an introductory guide to researcho n child languagea cquisition. It is in-
tended for advancedu ndergraduate,s graduate students, and researchersin cognitive
science, especially ones with interest in the psychology of language. Discussion of
research methods is couched within the framework of generative grammar, or what is
known as the theory of Universal Grammar. In part, we chose this framework because
of its emphasiso n explaining how children acquiren atural language. A distinguishing
feature of the theory of Universal Grammar is that it postulates principles that are
specifict o grammar formation, rather than attempting to cnaracterizela nguagea cqui-
sition using general principles of learning or cognitive growth (e.g., Chomsky 1971,
1975). Taken together, the linguistic principles of Universal Grammar constitute a
theory of the organization of the initial state of the mindjbrain of the language
leamer- that is, a theory of the human faculty for language.
In addition to linguistic competence, performancef actors also contribute to the lin-
guistic behavior of both children and adults. In our view, investigations of language
acquisition must be framedw ithin a specificm odel of performance. To assessc hildren's
underlying linguistic competence, it is necessaryt o understand the role of the com-
petenceg rammar within the performances ystem. Therefore, we will not focus solely
on researcho n child language acquisition, but will also discussa spectso f the perfor-
mance system within which the competence grammar resides.
1.1 Experimental Methods: Two Tasks
Our main motivation for writing this book is to help prepare students of language
acquisition to conduct experimentali nvestigations of children's linguistic knowledge.
We have not chosen to survey a variety of experimental techniques, however.1
Instead, we discussr esearcho n child languaged evelopment by explaining the design
featureso f two experimentalt echniquesf or assessingc hildren's linguistic competence:
one production task and one comprehensiont ask.
The production technique is known as the elicitedp roduction task. Experiments
using this task are designedt o evoke particular sentences tructuresf rom children. These
structures are elicited by devising situations that are uniquely felicitous for a specific
kind of sentence. For example, an experimenter might want to elicit declarative sen-
tences that contain a restrictive relative clause. The experimental situations are con-
structed with the meaning of the target sentence in mind; the result of the experiment
is a sentencet hat correspondst o that meaning in the child's grammar. In some case,s
the sentencesp roduced by children will be identical to those produced by adults,
but in other cases, children will produce nonadult structures. Children's nona dult
4 Chapter I
productions provide important insight into their grammars, and into the nature of the
acquisition processi tself.
The elicited production task is also used as a tool for ongoing, in-depth exploration
of individual children's grammars. Suppose, for instance, that a linguistic principle is
thought to have an effect on five different structures. These five structures could be
elicited from the same child subjects, to find out if the principle has the predicted
effect on children's grammars. It would be insightful to discover whether or not the
principle is in effect in all five structures, as predicted. Just as importantly, from a
methodological point of view, the properties of each structure can be further inves-
tigated using the elicited production task. In this way, a great deal of evidencec an be
gathered and a relatively Jlcomplete" picture can be assembledo f children's emerging
grammaticalp rinciples.
The comprehensiont echnique is known as the truth valuej udgmentt ask. This task
is used to investigate children's understandingo f the meaningso f sentence.s It is often
of theoretical interest to know whether or not children assign the samer ange of in-
terpretations to sentencest hat adults do. The truth value judgment task can be used
to tell if sentencesa re ambiguous or unambiguous for children and adults. The dis-
tinction between unambiguouss entencesa nd ambiguouss entencesp roves to be cru-
cial in demonstrating children's. adherencet o certain linguistic principles, known as
constraint.s The demonstration that children know a constraint involves showing that
they judge sentencesg overned by the constraint to be nonambiguous. Children who
lack a constraint should find the sentencest hat are governed by it to be ambiguous;
the interpretation ruled out by the constraint should be available to these children. In
assessingk nowledge of linguistic constraints, therefore, it is essentialt o understand
how children respond to ambiguous sentence.s Children's responsest o ambiguous
sentencesa re used as a yardstick for measuring their performancei n responding to
sentencesw ithin the jurisdiction of the constraint. In addition, it is sometimesw orth
knowing if children assignf ewer interpretations to certain constructions than adults
do. Becausec hildren are language learners, it is conceivable that they initially hy-
pothesize only a subset of the adult meaningsa nd later extend their interpretive op-
tions to include ones that were previously absen.t The truth value judgment task is a
useful tool for this purpose as well.
There are several reasonsf or examining child language using these two research
methods. First, these two tasks have proven to be especially revealing about chil-
dren's underlying linguistic competence. Theset asksa re particularly useful in assessing
children's knowledge of principles of Universal Grammar, that is, linguistic principles
that are likely to be innately specified. A secondr easonf or discussingt hese two tasks
in particular is that, when used properly, they are relatively free from the influence of
performancef actors that have been found to mask children's linguistic knowledge in
other tasks. Properly designeds tudies adopting the truth value judgment task and the
elicited production task have resulted in extremely consistent and reliable perfor-
mance by children- indeed, performancet hat is often on a par with that of adults.
Even when children's behavior differs from that of adults, the pattern of children's re-
sponsesi s so consistent that the responsesc an be confidently attributed to linguistic
knowledge and not to performancef actors. A final reason for focusing on these two
tasks is that they are, in large part, our own inventions; we know them well, and we
have refined them over the years to make them better tools for evaluating children's
Introduction 5
growing linguistic competence. We continue to use these tasks almost exclusively in
our own research .
By looking at the methodological prescriptions that have been administeredu sing
these tasks in our own prior research, we hope to convince a greater number of
students and researchersin child language of the basic correctnesso f the Innateness
Hypothesis and the theory of Universal Grammar. No one will be convinced, or
should be, by researcht hat is improperly designedo r poorly executed, or by findings
that are open to alternative interpretations. The methodological formulas presented
in this book are designed to overcome many of these obstaclest o the empirical in-
vestigation of children's linguistic competence. Researcht hat follows these method-
ological formulas will therefore have a better chanceo f being taken seriously, even by
critics of the theoretical assumptionst hat underlie the particular linguistic bent of the
researche.r Of course, no single experiment can control every potentially confound-
ing factor or rule out all but one explanation of the findings. However, this should
not deter researchersfr om attempting to conduct sound and tightly controlled em-
pirical investigations of child language. At the very least, the findings from carefully
designed studies can be replicated and cannot be dismisseda s artifacts of improper
procedureso r unnatural experimentalt asks.
1.2 Structure and Process
The book has three parts. Part I, encompassingc hapters 1- 16, is an extended dis-
cussiono f the fundamentala ssumptionst hat guide researchi n child languagea cquis-i
tion. Researchd oes not take place in a vacuum. Both the research questions of
interest and the methods that are employed to answer these questions depend on a
theoretical framework . This framework includes not only a theory of grammar, but
also a set of assumptionsa bout how grammar is embeddedi n a performances ystem.
As indicated earlier, we will assumet hat children's linguistic competencei s as de-
scribed by the theory of Universal Grammar. In part I, we outline certain linguistic
phenomenaa s they are viewed within this theoretical framework. The phenomenaw e
describe are characteristico f the researcht opics in child language that we return to
later in the book. We also explain why studies of children are especiallyp ertinent to
the investigation of these linguistic phenomena.
In addition to an explicit theory of linguistic competence, part I introduces a model
of languagep rocessing. In our view, this is essentialt o the investigation of children's
knowledge of linRuistic principles. Research findings from studies of child language
cannot be properly understood without an appreciationf or the languagep erformance
system within which linguistic principles operate for children and adults. It is beyond
the scope of this book to delve deeply into all aspectso f the performances ystem, but
we will present many of its relevant aspects, on the basis of our own conception of
the language apparatus and with support from the findings of experimental inves-
tigations of both children and adults.
A description of the general operating characteristicso f the performances ystem is
crucial to any serious investigation into children's knowledge of linguistic principles.
It is frequently lamented that there is an inherent tension between linguistic theory
and the kind of performance data that are obtained in experimental researchw ith
children (e.g., Cook and Newson 1996, 310). It is commonly held that linguistic
theory is "pure" and that performance data are "messy." As a theory of an ideal
6 Chapter 1
speaker -hearer 's linguistic behavior , it is assumed that a person 's competence qual -
itatively outstrips that person 's performance in any task . Without abandoning the
competence -performance distinction , we take issue with the notion that there is in -
herent tension between the competence grammar and the performance system in
which it is embedded . According to the model of language processing that we advo -
cate , " messy " data are not anticipated , even in studies with children . On this model ,
the competence grammar is ad versel y affected by performance factors . only in certain
circumstances (see Chomsky 1965 , 12 - 14 ). Assuming this model , we carefully exam -
ine the particular sites of friction between grammatical knowledge and performance
factors . One of the g-o als of the discussion is to explain how the interference of
Aperformance factors can be reduced in experimental s.tudies of child language . We
discuss strategies that result in optimal performance by subjects , because optimal
performance is a fundamental desideratum of experimental research .
1 .3 Competing Models of Language Acquisition
We advocate a specific model of the interrelations between linguistic representations
and linguistic performance , called the Modularity Matching Model (Crain and Wexler ,
forthcoming ). According to this model , children and adults share a common language -
processing system . Not only does this model assume that children have knowledge
of grammatical principles , just as adults do , but it goes on to make a further , more
contentious assumption : that children and adults appeal to the same processing
mechanisms of language production and language understanding (see Pinker 1984 ,
7 - 8 ). Finally , owing to the modular architecture of the language apparatus of both
children and adults , grammatical knowledge preempts nonlinguistic factors (e .g ., ex -
tralinguistic knowledge ) in most instances . The one exception is ambiguity . When a
sentence is ambiguous , nonlinguistic sources of information are sometimes used in
resolving the ambiguity . Nonlinguistic factors are not in competition with linguistic
knowledge for either children or aduJts , however , in producing or understanding un -
ambiguous sentences (see chapters 13 - 14 ).
According to the Modularity Matching Model , children 's linguistic performance in
any experimental task is expected to be essentially the same as that of adults , for both
ambiguous and unambiguous sentences . The model makes a further empirical pre -
diction as well . If linguistic performance is not typically marred by factors extraneous
to language , as the model maintains , then both children and adults should typically
behave in conformity with their linguistic knowledge . Of course , both children and
adults sometimes make mistakes , and children have been found to perform differently
than adults do , both qualitatively and quantitatively . But , because the possible sources
of children 's nonadult responses are quite limited from the perspective of the Modu -
larity Matching Model , any differences in the performance of children and adults
must be explained , or the model is brought into question . It is important , therefore , to
describe the ways in which the linguistic performance of children and adults can differ
according to the ~Modularity Matching Model , and to review and reexamine empiri -
cal findings that seem , at first glance , to be inconsistent with the model . The relevant
findings and the range of possible differences that are consistent with the model are
discussed in part I.
The chapters in part I also compare the Modularity Matching Model with two al -
ternative views of the interrelation between linguistic knowledge and other factors
Introduction 7
that contribute to linguistic behavior: environmental input, extralinguistic knowledge,
verbal short-term memory, and so on. One viewpoint that contrasts with the Modu-
larity Matching Model is called the Input Matching Model. This model assumest hat
children's grammars develop largely in responset o their linguistic input. Empirical
reasonsf or questioning the Input Matching Model are presentedi n chapter 5. That
chapter presentse videnceo f both children's nonadult productions and their nonadult
interpretations of sentence.s
Another alternative view of language and mind is called the CompetingF actors
Model. This model is pervasive in the literature on languagea cquisition. It is assumed
by most researchersw orking within the generative framework, even by researchers
who share with us many fundamental assumptions about the nature of linguistic
knowledge, including the InnatenessH ypothesis. These researchersd o not shareo ur
assumptionsa bout the relation between the. competenceg rammar and linguistic per-
formance, however. Researchersw ho adopt the Competing Factors Model view lin-
guistic knowledge as only one among several components contributing to linguistic
behavior in any experimental task. Therefore, on this model, less than perfect perfor-
mancei s expected in studies with children. This viewpoint has become so deeply in-
grained that most researcherss eemt o assumeit without argument. On the Modularity
Matching Model, by contrast, accesst o and application of linguistic principles pre-
empts the influence of other factors. On this model, therefore, children's performance
should parallel their linguistic competencei n many instances.
The Competing Factors Model is presented in detail in chapter 6. Chapter 6
also discussesb oth areasw here the Competing Factors Model and the Modularity
Matching Model converge, and areasw here they diverge. That chapter explains our
reasonsf or questioning the utility of researchd esignsa ssociatedw ith the Competing
Factors Model for the study of child language. Chapters 8 and 9 review many em-
pirical findings that seem to bear out the predictions of the Competing Factors
Model; these chaptersa nd the two that follow them, chapters 10 and 11, outline the
variety of research designs that have been employed by the model's advocates.
Chapters 12 and 13 present our responset o the Competing FactorsM odel. There we
argue againstt he basica ssumptionso f the model: that memory limitations (chapter 12)
and extralinguistic knowledge (chapter 13) interfere with children's accessto linguistic
principles.
Chapter 14 focuseso n one differenceb etween the language apparatuso f the child
and that of the adult: namely, that children have accesst o a languagea cquisitiond evice
(LAD).2 This differencel eadst o somei nteresting empirical consequencesa nd explains
certain apparent differencesb etween child and adult linguistic performance. Finally,
part I concludesw ith a consideration of what can go wrong in assessingc hildren's
linguistic knowledge (chapter 15) and a myriad of practical details in administering
experimentsw ith children (chapter 16).
We partition models of language and mind into three broad classesl argely for
purposeso f exposition. Making this partition permits us to comment on certain tasks
and researchs trategies that are commonly used in the study of child language, but
ones that we argue are inappropriate for studies of child language within the gen-
erative framework. In our view, the use of these tasks and researchs trategiesi mplies
the (implicit) acceptanceo f the Competing Factors Model. Becaused ifferent research
strategies are suggestive of different models, we have chosen to paint in broad
strokes those researchs trategiest hat are associatedw ith the different models.
B
Chapter 1
We hope to convince researchersw ho would adopt the Modularity Matching
Model that it is also necessaryt o adopt its methodological assumptionst o assess
children's knowledge of the principles and parameters of Universal Grammar. It
seems to us that many researchersa dopt the methodological assumptions of the
Competing Factors Model simply becauset hey are not aware of alternatives and be-
causet hey do not realize that the assumptionso f that model are inconsistentw ith the
theoretical framework they embrace. This book is our attempt to clarify the relation
between models of child languagea nd researchm ethodology. We argue that many of
the research strategies of the past should be abandoned in favor of new research
strategiest hat are more in keeping with a model of languagec ompetencea nd perfor-
mance that is based on the theory of Universal Grammar. One such model is the
Modularity Matching Model.
In making the case for a new set of researchs trategies, we inevitably take issue
with researchersw ho shareo ur commitment to incorporating insights from the syn-
tax and semanticso f generative grammar. We do so precisely becausew e believe that
this commitment demandsd ifferent researchs trategies. Through a critical examina-
tion of researchb y those of like concern, we hope to convince investigators "within
the family'! of the need to adopt alternative researchs trategies.
Part II of the book (chapters 17- 24) covers the elicited production paradigm, and
part III (chapters2 5- 40) covers the truth value judgment task. Becauseth ese are dy-
namic tasks and must be modified to addresss pecific researchq uestions, we provide
detailed discussiono f a number of experimentsu sing eachp aradigm. We include dis-
cussion of past and present researcht o illustrate particular design features of these
tasks.
A brief disclaimeri s called for. Although we review the theoretical background for
the syntactic, semantic, and discoursep rinciples that are the subject matter of the ex-
perimental investigations we describe, this book is not intended to replacea solid in-
troduction to linguistic theory.3 Readersw ithout a sufficient theoretical background
in linguistics may find that we presupposea firmer grasp of theory than they have.
We do not believe, however, that lack of familiarity with any of the theoretical
machinery we employ will interfere with proper understanding of the important
points of methodology, and this, after all, is what the book is about.
Chapter 2
Constraints and Universal Grammar
Universal Grammar is a theory of the human biological endowment for language,
that is, those aspectso f linguistic knowledge that are innately specified. Several em-
pirical hallmarks indicate that a biological property is innately specified. We use the
term hallmarksb ecausea linguistic property could be innately specifiedw ithout man-
ifesting certain of the relevant characteristic.s
One hallmark of innateness is that a property appears in the absence of decisive
evidencef rom the environment. If children adhere to-a linguistic principle for which
there is no corresponding evidencei n the environment, then the principle is likely to
be innately specified. In casesw here evidence for a linguistic principle is available in
the primary linguistic input, the evidence could actually lead learnersa stray, should
they try to avail themselveso f it. We will discusst wo such casesi n this chapter.
A related hallmark of innate specificationi s that children acquire a linguistic princi-
ple despite considerablel atitude in the primary linguistic data they encounter. If all
(or at least all normal) children in a linguistic community adhere to a particular prin-
ciple, despite being exposed to different input, then innate specificationi s suggested,
particularly if the principle is highly complex (from a pretheoretic vantage point).
Another hallmark of innatenessi s universality. If a linguistic principle is part of the
human biological blueprint for languageg rowth, then it is expected to be manifested
by children learning any natural language- hence the name Universal Grammar.
There are caveatst o this expectation, however. In certain instances, an innate linguis-
tic principle will not be expected to be exhibited in all languages. For example, the
parameterso f natural language (e.g., the null subject paramete)r are consideredt o be
innately specified. Although the various settings of a parameter may be innately
given, one setting may be manifestedb y one classo f languages, and another setting
by another class of languages. Moreover, it is not necessaryf or every option to be
manifestedd uring the course of development in a single language. If the initial value
of a parameteri s consistent with the target language, then other values will never be
adopted; they will simply atrophy, or go wherever unused parameter values go.
However, linguistic principles that are not parameterizeda re expectedt o appeari n all
languages, and in all children.1
A final hallmark of innatenessi s sometimess uggested: early emergence. It is not
logically necessaryf or innate principles and parameterst o emerge early in the course
of development. Just as some properties of physical development are biologically
timed to appear months, even years, after birth (e.g., the secondary sexual character-
istics), so certain aspectso f linguistic knowledge could become operative only at a
certain stage of development. In fact, two specific maturation accountsa re currently
at the forefront of child language research: Borer and Wexler (1987, 1992) propose
10
Chapter 2
that the capacity to form A-chainsm aturesi n children, and Radford (1990) and others
propose that certain functional projections mature. Regardlesso f the outcome of the
debates on these p- ro-posals, one should bear in mind that it is consistent with the
InnatenessH ypothesis for even (seemingly) highly complex linguistic principles to be
part of the young child's language faculty. Early emergenceo f linguistic principles
could be construed as additional evidenceo f innate s.p..ecification.
The alternative to innatenessi s learning; yet the early emergenceo f seemingly
complex linguistic principles casts doubt on many learning-theoretic scenarios. This
makes child language a good testing ground for innateness: it provides an oppor-
tunity to see whether or not particular linguistic principles meet the IIe arly emer-
gence" hallmark of innate specification.
2.1 The InnatenessH ypothesis
These joint expectations- that innate principles (a) emerge early, (b) are universal,
and (c) appear without decisive evidence from the environment- will be referred to
as the InnatenesHs ypothesi.s Much of the researchr eported in this book is concerned
with this hypothesis. Becauseth e focus is the study of child languagea cquisition, the
researchw e discuss examines two of the hallmarks of innateness: early emergence
and the mastery of linguistic principles by children in the absenceo f corresponding
experience. We interpret the results of this researcha s support for the InnatenessH y-
pothesis, generally, and as support for the theory of Universal Grammari n particular.
The remainder of this chapter outlines the kinds of linguistic phenomenat hat fall
within the confines of the theory of Universal Grammar and that are consequently
explored in this book.
2.2 Constraints
Unlike much current research, ours will not focus on what children say or on what
interpretations they assignt o sentence.s Instead, the emphasisw ill be on what children
do not say and on what meanings they do not assign to sentence,s when there are
grounds for thinking that they might say these things and assign these meanings.
The InnatenessH ypothesis is designed to solve this puzzle- why children do not
produce sentencest hat they might be expected to produce, and why they do not as-
sign meaningst hat they might be expected to assign. The relevant linguistic knowl-
edge comesi n the form of constraint,s of which this chapter will introduce two kinds.
Constraints of both kinds have been investigated using the experimental methods
describedi n subsequentc hapters.
Constraints are subject to the argument from the poverty of the stimulus, which
concludest hat knowledge of constraints cannot be learned and therefore is likely to
be innately specified. The argument from the poverty of the stimulus is the topic of
the next chapter. The remainder of this chapter will be devoted to constraints.
2.2.1 Sentenceasn d Meanings
To begin the discussion of constraints, we introduce some terminology. Following
Aristotle, we view languagea s pairings of sound and meaning. In more current terms,
language is conceived of as a (psychological) mapping between sentencesa nd their