universiteit van amsterdam december 14-16, 2007 | 1 reinhard blutner [email protected]...

December 14-16, 2007 | 1

universiteit van amsterdam

Reinhard Blutner

http://www.blutner.de

[email protected]

Optimality-Theoretic Pragmatics Meets Experimental PragmaticsExperimental Pragmatics Conference, Humboldt University, Berlin, December 14-16, 2007

Institute for Logic,Institute for Logic,Language and Language and ComputationComputation

December 14-16, 2007 | 2


0 Introduction

“With four parameters I can fit an elephant, and with five I can make him wiggle his trunk”

(John von Neumann) as quoted by Freeman Dyson in "A meeting with Enrico Fermi"

December 14-16, 2007 | 3


Grice and His Followers

Relevance Theory

Presumptive Meanings

Neo-Gricean

Theories (Horn, Atlas)

OT-Pragmatics

December 14-16, 2007 | 4


Experimental Pragmatics

“Properly devised experimental evidence can be highly pertinent to the discussion of pragmatic issues, and pragmatics might greatly benefit from becoming familiar with relevant experimental work and from contributing to it ”(Noveck & Sperber 2007, p. 210)

December 14-16, 2007 | 5


Optimality Theoretic Pragmatics

› Like generally in OT: no artificial boundary between competence and performance

› Bidirectional grammar (constraint-based)

› NL comprehension as interpretive optimiz-ation

› NL production as expressive optimization

December 14-16, 2007 | 6


Open Issues

› Are the two optimization processes integrated with each other (bidirectional optimization)?

› How to explain the asymmetries between comprehension and production?

› The role of fossilization/conventionalization?

December 14-16, 2007 | 7


The Idea of Fossilization› ‘Invited Inferences’ (Geis & Zwicky 1971). Mechanism

of conventionalization for implicatures

› Short-circuited implicatures (Morgan 1978; Horn & Bayer 1984)

› Lexicalization (Cole 1975)

› Traugott (1989…2005) applied the idea to explain language change

› Levinson (2000) und Mattausch (2004) used the idea for explaining the development of binding.

December 14-16, 2007 | 8


Outline

1. Pronouns/Reflexives with children and adults

2. R-expressions/Pronouns with young and elderly adults

3. All/Some (Scalar Implicatures) with children and adults

4. Conclusions

December 14-16, 2007 | 9


1 Pronouns/Reflexives

In an important recent article Hendriks and Spenader (2004) give a new interpretation of children‘s delay of the comprehension of pronouns. I discuss the validity of this interpretation and present an alternative account in terms of iterated learning

December 14-16, 2007 | 10


Children’s comprehension of reflexives*› Here is an elephant and an alligator. The

elephant is hitting himself.

› Question: Does the sentence match the picture?› Children from age 4 on: Yes

* I thank Petra Hendriks for allowing me to use her slides

December 14-16, 2007 | 11


The pronoun interpretation problem› Here is an elephant and an alligator. The

elephant is hitting him.

› Question: Does the sentence match the picture?› Children until at least the age of 6 or 7: Yes

E.g., Chien & Wexler, 1990; Grimshaw & Rosen, 1990; Jakubowicz, 1984; Koster, 1993; McDaniel, Smith Cairns, & Hsu, 1990; McDaniel & Maxfield, 1992; McKee, 1992.; Spenader, Smits & Hendriks, subm.

December 14-16, 2007 | 12


Children’s production of pronouns

› Task: Describe what you see on the picture.

› Children between 4;6 and 7:

The elephant is hitting him.

Cf. De Villiers, Cahillane, & Altreuter, 2006; Spenader, Smits, & Hendriks, subm.

December 14-16, 2007 | 13


Children’s production of reflexives

› Task: Describe what you see on the picture.

› Children between 4;6 and 7:

The elephant is hitting himself

*The elephant is hitting him

December 14-16, 2007 | 14


Production/comprehension asymmetry› Production results show that very young

children have competence of binding principles› But if this is true, then why don’t they use this

knowledge in comprehension?

› Usually, comprehension of a given form precedes production of this form (Bates, Dale and Thal 1995; Benedict 1979; Clark 1993; Fraser, Bellugi and Brown 1963; Goldin-Meadow, Seligman and Gelman 1976)

› How do we reconcile children’s poor performance on comprehension tasks with their near-perfect production data?

December 14-16, 2007 | 15


1.1 Hendriks & Spenader‘s Account

Hendriks’ and Spenader’s (2004) model accounting for children‘s delay of the comprehension of pronouns. The model assumes delayed bidirection.

December 14-16, 2007 | 16


Optimality Theory as a Framework

Contraint-Hierarchy:C1 >> C2 >> C3 Evaluator

Output

Input

Generator

1 2 3 4 5Candidates

December 14-16, 2007 | 17


Unidirectional OT

› Consider two directions of optimization (Hearer-oriented, Speaker-oriented)

› Use the same set of constraints and the same ranking for both perspectives

› Hence, the evaluator evaluates pairs of representations (e.g. form-meaning pairs)

December 14-16, 2007 | 18


Constraints (slidely modifying Burzio 1998)

› PRINCIPLE A: A reflexive must be bound locally› REFERENTIAL ECONOMY:

Avoid R-expressions >> Avoid pronouns >> Avoid reflexives

pro

self

disj conj

pro

self

disj conj

PRINCIPLE A REFERENTIAL ECONOMY

December 14-16, 2007 | 19


Assuming a Ranking

› PRINCIPLE A >> REFERENTIAL ECONOMY› Hearer‘s perspective: one optimal interpretation

for self but two optimal interpretations for pro.› Speaker‘s perspective: correct unique form for

each interpretation.

pro

self

disj conj

pro

self

disj

conj

December 14-16, 2007 | 20


Bidirectional OT

pro

self

disj conj

pro

self

disj

conj

When hearing a pronoun, a bidirectional actor reasons about what other non-expressed forms the speaker could have used, compare the interpretation associated with the pronoun and realize that a coreferential meaning is better expressed with a reflexive. Then, by a process of elimination, she must realize the pronoun should be interpreted as disjoint.

Strong bidirection = Consider both directions of optimization simultaneously

December 14-16, 2007 | 21


Delayed Bidirection› The proposal is that children begin with

unidirectional optimization, and only later acquire the ability to optimize bidirectionally.

› Optimizing bidirectionally inherently involves reasoning about alternatives not present in the current situation, which may be a skill acquired very late, thus explaining the lag in acquisition.

› Optimizing bidirectionally requires more processing resources than unidirectional optimization

December 14-16, 2007 | 22


Advantages› The authors are able to derive Principle B effects

from Principle A alone, through bidirectional optimization.

› The analysis clearly distinguishes the task of a speaker from the task of a hearer. As a result the analysis is able to model different results for production and comprehension.

› Besides the stipulation of the constraints and their ranking no other stipulations are required

› The approach nicely combines a pragmatic explanation with a processing account (lack of processing resourses)

December 14-16, 2007 | 23


Disadvantages

› The constraints are partly stipulated - no constraint grounding

› Theory of Mind (Perner, Leekam and Wimmer 1987) requires awareness of other conversation participant’s choices. Hence, theory of mind is based on controlled reflection rather than automatic processing. However, the effects of pronoun processing are nearly automatic. There is no explicit hint for mind reading capacities in such tasks.

December 14-16, 2007 | 24


Rather than stipulating a change from uni-directional to bidirectional processing I account for the effects of bidirection by a mechanism of learning/automatization (changing the constraint ranking)

1.2 A Model in Terms of Learning/ Fossilization

December 14-16, 2007 | 25


Learning as Utility Optimization

› Learning consists in improving the value of expected utility (measuring the success of communication)

› In OT-learning theories the ranking of a given system of constraints is (stepwise) changed

› Learning leads to a stable outcome if the relevant EU(s) reach its maximum value

December 14-16, 2007 | 26


A Very Simple Learning Algorithmm f m’

Speaker

Hearer

m = m’ ?

If yes, nothing happens

If no, adjustment:

All constraints that favour (f, m) over (f, m’) are promoted

All constraints that favour (f, m’) over (f, m) are demoted

December 14-16, 2007 | 27


Application: Fossilization

› Principle A: self conjoint› Referential Economy: self >> pro› Principle B: pro disjoint; ….

pro

self disj conj

pro

self

constraint B strengthened

disj

conj

conj

Speakerself

Hearernothing happens

conjconj

Speaker pro

Hearernothing happens

disjdisj

December 14-16, 2007 | 28


Conclusion: Two models

› Processing account (unidirectional versus bidirectional processing)

› Fossilization account (applying OT learning theory). This view is related to an instance theory of automatization (Logan 1988)

› Conceptual advantage of the fossilization account: no mind reading capacities are required for the processing tasks

December 14-16, 2007 | 29


Two kinds of fossilization

› Individual fossilization via learning/automatication on an ontogenetic time scales (seconds-years)

› Cultural fossilization via iterated learning/cultural evolution on a historical time scale (years-centuries)

Meanings are partly conventionalized within speech communities and partly negotiated anew during each individual interaction (Traugott & Dasher 2002)

December 14-16, 2007 | 30


2 R-Expressions/Pronouns

Hendriks, Englert, Wubs & Hoeks (to appear): Age differences in adults’ use of referring expression

December 14-16, 2007 | 31


Sentence Elicitation Study

A woman hold-ing an ice cream cone is walking past a road sign.

The woman comes across a girl.

She gives the girl an ice cream cone.

The girl is eating from the ice cream cone.

Well, the woman passes again an ice cream van.

The woman buys another ice cream come.

Topic shift Target Picture

she

December 14-16, 2007 | 32


Results› Elderly adults produce (non-recoverable)

pronouns significantly more often than young adults when refer-ring to the old topic in the presence of a new topic.

› With respect to the comprehension task, no significant differences were found between elderly and young adults.

December 14-16, 2007 | 33


Bidirectional Processing Account

› Speakers optimize bidirectionally and take hearers into account when selecting a referring expression.

› If the use of a pronoun will lead to an unintended interpretation by the hearer, the speaker will use an unambiguous definite noun phrase instead.

› Because elderly adults are more limited in their processing capacities as speakers they will not always be able to reason about the hearer’s choices.

December 14-16, 2007 | 34


Discussion› Fits nicely with the earlier approach for

pro/self› Right prediction for elicitation studies:

elderly adults behave similar to children› Wrong prediction for pronoun/reflexive

interpretation studies: elderly adults should behave similar to children

› Elderly (or stressed) people have no problems with understanding pronouns; the problems are in production only: it is complex to use an unambiguous definite noun phrase instead of a pronoun in certain situations

December 14-16, 2007 | 35


The Fossilization Account

› The fossilization account is also able to describe the difference between children and adults

› Learning leads to strengthening of PRO TOPIC

› Unfortunately, it predicts that elderly adults behave similarly to younger adults in case of R-expressions/pronouns (there is no de-fossilization!)

› Wrong prediction! They should behave like children.

December 14-16, 2007 | 36


Emergence of Bidirection or Fossilization?› According to the bidirectional processing account

the crucial developmental stages should appear synchronously for the different domains

› According to the fossilization solution (iterated learning) the time course of the development is not necessarily synchronized but may crucially depends on factors of frequency and other factors of use

› Investigate different domains of structural similar tasks!

December 14-16, 2007 | 37


3 All/Some (Scalar Implicatures)

December 14-16, 2007 | 38


Some and all

› Experimental Pragmatics: Noveck u.a.

• Some elephants live in the zoo (appropriate) yes 90% 99%

• All elephants live in the zoo (inappropriate) no 99% 99%

• Some elephants have trunks (inappropriate) yes 85% 41%

• All elephants have trunks (appropriate) yes 99% 96%

• Some elephants have wings (absurd) no 99% 98%

• All elephants have wings (absurd) no 99% 99%

› Why do children sometimes think more logical than adults?

Adults10-11

December 14-16, 2007 | 39


Potential Answers

› RT (finding relevant enrichments is somewhat effortful – children’s processing resources are rather limited; see Noveck & Sperber)

› OT pragmatics has two potential answers

(1) Metalinguistic ability for perspective changing (bidirectional reasoning) not yet developed

(2) Fossilization not yet progressed

December 14-16, 2007 | 40


pro

selfdisj conj

pro

self

disj

conj

some

all

some

all

7 years old

12 years old

December 14-16, 2007 | 41


Conclusions

› The existence of domain-dependencies is a strong argument for the fossilization view

› Fossilization is a graded mechanism. In some cases it can lead to full automatization (corresponding to Levinson‘s GCI); in most cases it will not

› It is difficult to see how the bidirectional processing account (and the RT processing account) can model domain-dependencies without assuming an extra automatization mechanism.

December 14-16, 2007 | 42


4 General Conclusions

December 14-16, 2007 | 43


Final Scores: Comprehension/ProductionBidir. Processing

(Hendriks et al.)OT with

Fossilization

Pronouns & ReflChildren

Young adultsElderly adults

+/++/+−/+

+/++/++/+

R-Exp & PronChildren


+/++/++/+

+/++/++/−

All & SomeChildren


+/++/+

?

+/++/+

?

December 14-16, 2007 | 44


Conclusions› Production/comprehension asymmetries arise

as a result of a mismatch between the result of unidirectional optimization and the result of bidirectional optimization

› The asymetries can disappear- when the language user is able to optimize

bidirectionally- when fossilization has taken place

› Both the bidirectional processing view and the fossilization view are not really sufficient if taken per se

December 14-16, 2007 | 45


Towards a Solution

› Combining the idea of Fossilization with asymmetric OT

› In asymmetric OT the speaker takes the listener into account but not vice versa

› We need independent motivation for that. At the moment it’s a data fitting only!

With four parameters I can fit an elephant, and with five I can make him wiggle his trunk

universiteit van amsterdam december 14-16, 2007 | 1 reinhard blutner [email protected]...

Documents