Date 15.08.2008
Bidirectional OT and
language acquisition
Petra Hendriks
ESSLLI 2008 course “Bidirectional OT in natural language”
Hamburg, August 15, 2008
Comprehension
Date 15.08.2008
>Here is an elephant and an alligator.
>The elephant is hitting
himself.
Children: NO
>The elephant is hitting
him.
Children: YES
>The elephant is hitting
himself.
Children: YES
>The elephant is hitting
him.
Children: YES
Puzzle
Date 15.08.2008
Production/comprehension asymmetry:
>Pronoun Interpretation Problem
(e.g., Jakubowicz, 1984; Chien & Wexler, 1990; Grimshaw
& Rosen, 1990, for English; Deutsch, Koster & Koster,
1986; Koster, 1993; Philip & Coopmans, 1986, for Dutch)

The elephanti is hitting himi/j

Until 6-7 years old
>However, children’s production is adult-like
from age 4 on!
(de Villiers, Cahillane & Altreuter, 2006, for English;
Spenader, Smits & Hendriks, in press, for Dutch)
Production
Date 15.08.2008
>Children: The elephant
is hitting him/the
alligator.
>Cf. adults
>Children: The elephant
is hitting himself.
>Cf. adults
(Spenader, Smits & Hendriks, in press)
Binding Theory
Date 15.08.2008
Binding Theory (Chomsky, 1981):
>Principle A: A reflexive must be bound in its
local domain.
>Principle B: A pronoun must be free in its
local domain.
How can comprehension of pronouns be
delayed, while production of pronouns is adultlike?
Explanations
Date 15.08.2008
Explanations of PIP: Children possess the
linguistic knowledge, but make errors due to:
>Lack of relevant pragmatic knowledge
(e.g., Chien & Wexler, 1990; Thornton & Wexler, 1999)
>Interference of task factors
(e.g., Bloom, Barss, Nicol & Conway, 1994; Grimshaw &
Rosen, 1990)
>Lack of sufficient processing resources
(e.g., Avrutin, 1999; Reinhart, 2006)
Aim
Date 15.08.2008
If the Pronoun Interpretation Problem lies
outside the grammar:
>Why is production unaffected?
>Why does the PIP not arise in all languages?
>Why does the PIP not arise in all constructions
in a language?
Aim of this talk: Investigate the hypothesis
that the PIP (and other asymmetries) can be
explained from the grammar itself.
Outline
Date 15.08.2008
Outline:

The grammar: Optimality Theory

Constraint reranking

OT is a direction-sensitive grammar

Production/comprehension asymmetries

Bidirectional OT results in a symmetric
system

Predicting further asymmetries in acquisition
(e.g., PIP, subject anaphora)
Optimality Theory
Date 15.08.2008
Markedness constraints, e.g.:
 NoCoda: No syllables with a coda.
 *Dors: No dorsal segments.
Faithfulness constraints, e.g.:
 Parse: No unparsed underlying material.
 Fill: No insertion of new material.
Constraint reranking
Date 15.08.2008
Language acquisition involves constraint
reranking:

Input:
FAITH
MARK
/kæt/
(Parse, (NoCoda,
Fill)
*Dors)
[kæt]
[ta]
*
*!
Tableau 1
Adults’ grammar:
FAITH >> MARK
Input:
MARK
FAITH
/kæt/
(NoCoda,
*Dors)
(Parse,
Fill)
[kæt]

[ta]
*!
*
Tableau 2
Children’s grammar:
MARK >> FAITH
Smolensky (1996)
Date 15.08.2008
Production and comprehension yield different
results:
Input:
MARK
/kæt/
(NoCoda, (Parse,
*Dors)
Fill)
[kæt]

[ta]
FAITH
*!
*
Tableau 2
Children’s grammar:
Production

Input:
MARK
FAITH
[kæt]
(NoCoda,
*Dors)
(Parse,
Fill)
/kæt/
/hæt/
*!
Tableau 3
Children’s grammar:
Comprehension
Output-oriented
Date 15.08.2008
>Optimality Theory is output-oriented:
 Markedness constraints penalize outputs
 Faithfulness constraints penalize input-output
mappings
>If the direction of optimization is reversed, this
affects the application of markedness
constraints (but not faithfulness constraints).
Direction-sensitive
Date 15.08.2008
>Production: Meaning  form
 Faithfulness constraints
 Markedness constraints on form
>Comprehension: Form  meaning
 Faithfulness constraints
 Markedness constraints on meaning
>Because different constraints apply in the two
directions of optimization, OT is directionsensitive.
Comprehension delay?
Date 15.08.2008
So there is evidence for early delays in
production. Do we find similar delays in
comprehension?
Yes, if Chapman & Miller (1975) are right in that
production precedes comprehension w.r.t.
early word order.
>The car is pulling the cow.
(A)symmetry
Date 15.08.2008
>Q: Does the adult constraint ranking always
result in the same pairing of form and
meaning in production and comprehension?
>A: This depends on the constraints. Particular
combinations of constraints give rise to a
different pairing in production and
comprehension.
Example: Object pronouns
Pronouns
Date 15.08.2008
>Principle A (FAITH):
No reflexives with a locally disjoint meaning.
>Referential Economy (MARK):
No full NPs >> No pronouns >> No reflexives
(Principle B need not be assumed, but rather is
a derived effect)
Production
Date 15.08.2008
Production yields the adult forms:

Input:
FAITH
MARK
coref.
Principle Ref
A
Econ
reflexive
pronoun
Input:
FAITH
disjoint
Principle Ref
A
Econ
reflexive
*!
Tableau 4
Production of
coreferential meaning

pronoun
MARK
*!
*
Tableau 5
Production of disjoint
meaning
Comprehension
Date 15.08.2008
But comprehension results in a non-adult
pattern:
Input:
FAITH
MARK
reflexive Principle Ref
A
Econ

coref.
disjoint
*!
Tableau 6
Comprehension of
reflexive


Input:
FAITH
MARK
pronoun
Principle Ref
A
Econ
coref.
disjoint
Tableau 7
Comprehension of
pronoun
Ambiguity
Date 15.08.2008
This is exactly children’s pattern w.r.t. the
Pronoun Interpretation Problem.
>Q: But why aren’t pronouns ambiguous for
adults?
>A: Because adults optimize bidirectionally,
whereas children are not yet able to do so.
(de Hoop & Krämer, 2005/6; Hendriks & Spenader, 2005/6;
Hendriks et al., Conflicts in interpretation)
Blutner (2000)
Date 15.08.2008
Bidirectional optimization (Blutner, 2000):
A form-meaning pair <f,m> is bidirectionally
optimal iff:
a. there is no other bidirectionally optimal pair
<f’,m> such that <f’,m> is more harmonic
than <f,m>.
b. there is no other bidirectionally optimal pair
<f,m’> such that <f,m’> is more harmonic
than <f,m>.
Bidirectional OT
Date 15.08.2008
A symmetric system arises through
bidirectional optimization:
FAITH
MARK
Principle Ref
A
Econ


<reflexive, coref.>
<reflexive, disjoint>
Tableau 8
Bidirectional
optimization of
anaphoric
objects
*
<pronoun, coref.>
*
<pronoun, disjoint>
*
 Principle B
Language acquisition
Date 15.08.2008
Language acquisition in bidirectional OT:
>Initial constraint ranking
(presumably MARK >> FAITH)
>Error-driven constraint reranking
(e.g., Tesar & Smolensky, 1998; Boersma & Hayes, 2001)
>Adult constraint ranking
>From unidirectional to bidirectional
optimization
Bidirectional OT
Date 15.08.2008
How can we decide between biOT explanation
and alternative accounts?
>Alternative accounts predict that production in
general is relatively easy.
Example: Subject pronouns
Him
Date 15.08.2008
Ladies and gentlemen, we got him!
Paul Bremer at press conference in Baghdad, 14 Dec.
2003
Topic
Date 15.08.2008
Pronouns refer to very salient referents, usually
mentioned in the linguistic discourse.
>ProTop (FAITH):
No pronouns that refer to a non-topic.
Recoverability
Date 15.08.2008
The adult pattern can be modeled by
bidirectional optimization:


MARK
FAITH
Ref
Econ
Pro
Top
<pronoun, +topic>
<pronoun, -topic>
*
<full NP, +topic>
*
<full NP, -topic>
*
Tableau 9
Bidirectional
optimization of
anaphoric
subjects
Predictions
Date 15.08.2008
Predictions with respect to production:

Input:
MARK
FAITH
Input:
MARK
FAITH
+topic
Ref
Econ
Pro
Top
-topic
Ref
Econ
Pro
Top
pronoun
full NP
*!
Tableau 10
Production of topical
referent

pronoun
full NP
*
*!
Tableau 11
Production of nontopical referent
Predictions
Date 15.08.2008
Predictions with respect to comprehension:

Input:
MARK
FAITH
Input:
MARK
FAITH
pronoun
Ref
Econ
Pro
Top
full NP
Ref
Econ
Pro
Top
+topic
-topic
Tableau 12
Comprehension of
pronoun
*!


+topic
-topic
Tableau 13
Comprehension of full
NP
Experiment
Date 15.08.2008
>If children are unable to optimize
bidirectionally, it is predicted that:
 They overuse pronouns to refer to nontopics.
 They fail to interpret full NPs as marking a
topic shift.
>This was tested in a production/
comprehension experiment with 4- to 6-yearold Dutch children.
(Wubs, Hendriks, Hoeks & Koster, to be presented at
GALANA 3)
Date 15.08.2008
Date 15.08.2008
A pirate is walking
with a ball.
He kicks away the
ball.
But then the ball falls
into the water and
he starts to cry.
A knight arrives with He scoops the ball And then the pirate has
a fishing net.
out of the water.
his ball back again.
Results
Date 15.08.2008
% produced forms
Children (4-6 y.o.)
Adults
100
100
80
80
97
59
60
60
37
40
40
20
20
3
4
0
0
0
Pronoun
Full NP
Other
Pronoun
Full NP
Other
Production of referring expression to refer to
old topic after topic shift
Egocentric
Date 15.08.2008
Adults:
>And then the pirate has his ball back again.
Many children:
>And then he has his ball back again.
By using a non-recoverable pronoun, children as
speakers do not take into account the hearer.
This suggests lack of bidirectional optimization.
Another prediction
Date 15.08.2008
Prediction: Pronoun Interpretation Problem
disappears if there is a clearly established topic.
Input:
FAITH
pronoun
Principle Ref
A
Econ
coref. &
-topic

MARK FAITH
Pro
Top
*!
disjoint &
+topic
Tableau 14
Comprehension of pronoun
PIP dissolves
entirely in single
topic context:
“Here is an alligator.
The elephant is
hitting him”
Spenader, Smits &
Hendriks, in press
Asymmetries
Date 15.08.2008
Bidirectional OT predicts four types of
asymmetries:
Young children Older children
(<4 years old)
(>4 years old)
Delay in
production
First words
Delay in
Early word
comprehension order?
Anaphoric
subjects
Pronoun
Interpretation
Problem
Development
Date 15.08.2008
How does bidirectional optimization develop?
>Blutner & Zeevat (2004): Pragmatic reasoning
about form-meaning pairs that can become
conventionalized
>Hendriks, van Rijn & Valkenier (2007): Online
mechanism, dependent on processing
resources:
 Form  meaning  form
 Meaning  form  meaning
Processing
Date 15.08.2008
Do processing resources matter? YES
>Also overuse of subject pronouns by elderly
adults (>60 years old).
(Hendriks, Englert, Wubs & Hoeks, 2008)
>Overuse of subject pronouns appears to be
related to working memory capacity.
(Wubs, Hendriks, Hoeks & Koster, to be presented at
GALANA 3)
>Children’s comprehension of object pronouns
improves when speech is slowed down.
(Van Rij-Tange, Hendriks, Spenader & Van Rijn, to be
presented at GALANA 3 & BUCLD 33)
Other explanations
Date 15.08.2008
Can the data also be explained by extragrammatical factors?
>Pragmatic knowledge: Separate explanation
required for each phenomenon
>Task factors: Methodological pessimism
>Processing limitations: May account for late
asymmetries, but weaker explanation
Testing theories
Date 15.08.2008
Conclusions
Date 15.08.2008
Because OT is direction-sensitive, it allows for a
straightforward explanation of
production/comprehension asymmetries in
language acquisition:
>Early asymmetries can be explained as the
result of a non-adult constraint ranking.
>Late asymmetries can be explained as the
result of the inability to optimize
bidirectionally.