Informativeness, Relevance and Scalar Implicature

Author: Roybn Carston

Presenter: Ovidiu Fortu

Outline

IntroductionPragmaticsPrinciples underlying the implicature

phenomenonTypes of implicaturesExamples

Introduction

Pragmatics Implicature = anything that is inferred from

an utterance but that is not a condition for the truth of the utterance. (Gazdar, 1979)

Presupposition = anything that is presupposed to be true given an utterance

Presupposition

Possible criterion: given an utterance U, the proposition p that is inferred by listener from both U and not U is a presupposition

Example: The king of France is bold. The king of France is not bold.

From both sentences, the affirmation and the negation, we infer that there is a king of France

Implicature

Implicatures are inferred based on the assumption that the speaker observes or flouts some principles of cooperation (different authors have identified different principles)

Grice – 4 principles (so called “maxims”)Levinson (1981), Horn (1984) – 2

principles

Grice Principles

Quantity maxim the communication must be adequately but not

overly informative Quality maxim

the speaker does not believe it to be false and has adequate evidence for his statement

Maxim of relation or relevance the communication must be relevant

Maxim of manner the communication must be clear, unambiguous,

brief, and orderly

Grice Principles, reduced form

The Q-principleSay as much as you can (given I)

The I-principleSay no more than you must (given Q)

Types of Implicatures

Standard implicature – based on the assumption that the speaker observes the cooperation principlesA: I’ve just run out of petrol.B: There is a garage just around the corner.

B infers that he can find oil at the garage.

Types of Implicatures

Flouting implicatures – based on the assumption that the speaker deliberately flouts one of the communication principlesA: The capital of Morocco is CasablancaB: Yes, and the capital of U.K. is Moskow

A infers that his statement was wrong.

Types of Implicatures, another classification

Generalized implicatures – inferred without a special reference to context:John walked into a house yesterday. Infer that the house was not John’s house

Particularized implicatures – inferred only due to a special contextA: Can you tell me the time?B: Well, the milkman is here.It must be the time when the milkman comes.

Properties of Implicatures

Strong dependency on context (see the complex implicature example)

Defeasibility (they are not entailments, and addition of new facts can cancel them)

Why is the problem of implicature hard?

Deals with the “logic defying” aspects of communication

The cooperation principles are hard to formulate (work is still done in this area, and no author claims he has a final form of the principles)

Implicatures are “hidden”, i.e. they do not appear in text, which makes a statistical approach less accessible

Scalar Implicature

Lexical (and logical) scales:all, most, many, somenumberssubset, set

According to the cooperation principles, the speaker must use the right member of the scale

Scalar Implicature, Examples

Bill has got some of Chomsky’s papers Infer that Bill does not have all the Chomsky’s

papers There will be five of us for dinner tonight

Infer that there will not be more than five of us for dinner tonight

A: I like Mary. She is intelligent and good hearted.

B: Yes, she is intelligent. Infer that B thinks Mary is not good-hearted

Complex Scalar Implicatures

Scenario: Kai’s parents promise him rewards for things he does not like to do: a small reward for washing his hair, a medium reward for eating broccoli and peas, and a high reward for cleaning up his room.

Kai’s mother says: Kai had broccoli and peas.

We infer that Kai did not clean up his room

Scalar Implicatures

Based on the Q-principleThe speaker must not make a weaker claim

(i.e., he must say as much as he can, as long as this does not increase the effort)

It takes the same amount of effort to say:John walked into his house yesterday.John walked into a house yesterday.

Other Types of Scales

Ranked entities:A: Is Jill a professor yet?B: She’s a senior lecturer.Infer that Jill is not a professor.

Whole/part relationA: Did you manage to read that chapter I

gave you?B: I read the first couple of pages.Infer that B didn’t read the whole chapter.

Other Types of Scales

Instance-ofA: Do you have any juice?B: I have grape, orange and tomato.Infer that B does not have any apple, lemon..

Alternate values (not necessarily ordered)A: Did you get Paul Newman's autograph?B: I got Joanne Woodward's.B didn’t get Newman’s autograph

Quantity principle, refined

Welker (1994) shows that the quantity principle, as formulated by Grice, is too strong: A: I'm having a dinner party and I need four more

chairs. B: John has two chairs.

Implicature: B has at most two chairs A: I'm having a dinner party and I need four more

chairs. B: John has four chairs.

This time, no implicature

Quantity principle, refined

Communication must be "... as informative as is required (for the current purposes of the exchange)"

Idea: even the scalar implicatures depend on context – not only the surrounding text, but also the situation

False Predictions

Not all scales generate implicatures all the time

The relevance principle may cancel some scalar implicatures:A: What did you buy for your mother?B: I bought her flowers.

Assuming that roses are on top of the flowers scale, this leads to the implicature “I didn’t buy her roses”.

False Predictions, continued

The implicature is not inferred because the statement is relevant enough

However, a possible implicature in this example is “I didn’t buy her a present”. The difference is that while it is not relevant which kind of flowers he bought, it is relevant whether he bought a present or not

Matsumoto’s constraint

Let <S, W> be a scale (with S stronger than W)

Then a scalar implicature is inferred if the following condition is met: the choice of W instead of S must not be

attributable to the observance of the maxims of quantity-2, relation or obscurity avoidance (manner-1).

Matsumoto’s constraint, contd

Equivalently, observing the quantity-2, non-obscurity and relevance takes precedence over observing quantity-1

Idea: the relevance maxim seems to hold the key to the process of inferring implicatures

“Affirmative” Implicatures

So far, the scalar implicatures seem to simply negate the stronger claim when the weaker is presented

We can also have implicatures that do not involve negation: If you finish your thesis by September you'll be

eligible for the job. Implicature: You'll be eligible for the job if and only if

you finish your thesis by September.

Pragmatic Schemes

Let S and W be members of a scale, with S stronger than W

Q-based implicature:S entails W"W" implicates "not S"

R-based implicature:S entails W"W" implicates "S"

Pragmatic Schemes, applied

[P and Q] entails [P or Q] "[P or Q]" Q-implicates "[not [P and Q]]" Thus the implicature is not P or not Q, or “only one

of P and Q can hold”

[P iff Q] entails [if P, Q] "[if P, Q]" R-implicates "[P iff Q]" “If you finish your thesis by September you will be

eligible for the job” – as seen above, the implicature is that the condition is necessary

Informativeness

In both previous examples, the implicatures enrich the informational contents of the message

Observation: What is conveyed always implies logically what is said

Conclusion: the implicature mechanism allows the quantity of information in a message to grow

Richardson&Richardson critique

I broke a finger. implicates: I broke one of my own fingers.

I found a finger. implicates: I found someone else's finger.

Which of the schemes can be applied?Q-implicatures or R-implicatures?Again, relevance is the key

Cardinal numbers

Problem: A and B go to a party. They make a bet, A says that there will be 20 people at the party when they arrive. When they get to the party, there are 25 people. Who wins the bet?

Cardinal numbers, ambiguity

The source of ambiguity is the use of numbers; the sentence “there will be 20 people” can be used to express:There will be at most 20 people there.There will be exactly 20 people there.There will be at least 20 people there.

The context of the bet supports the second interpretation

Cardinal numbers, continued

In Britain you have to be 18 to drive a car.

The new houses are big enough for families with three children.

A default reasoning (world knowledge is essential) decides the interpretation (“at most” – “at least”)

Conclusions

The Q principle and R(I) principle give rise to the same result: a strengthening of the meaning of the utterance

The relevance principle plays a key role, which constrains the Q and R principles

Cardinal numbers are a special case of scale; they allow punctual interpretation, but also interval interpretation

Scalar implicatures: experiments at the semantics–pragmatics interface

Authors: Anna Papafragoua, Julien Musolinob

Presenter: Ovidiu Fortu

Paper contents

A study of how scalar implicatures are inferred by humans

Two sets of experiments are performed with a group of young children to test their ability to infer implicatures

Only scalar implicatures are considered for the tests

First Set of Tests

Subjects:30 5-year-old children and 30 adults, all native speakers of Greek (all experiments in Greek)

Three scales :oli, meriki (all, some) tris, dio (three, two) teliono, arxizo (finish,start)

Experiment setup

Subjects are presented a situation that allows a stronger claim

Subjects (both adults and children) answer questions about the situation

Questions admit yes/no answers (the subjects must assess the truth value of a claim in the given context

Results

While adults have no problem of inferring implicatures, children seem to be less sensitive to weak clauses

Only 10% - 12.5% of the weak claims in case of scale (all, some)

However, for other scales, children have better results – 65% in case (three, two), which shows that different scales are perceived differently

Justifications for Answers

Subjects were also required to provide a brief justification for their answers Adults overwhelmingly justified their answers by

stating the stronger claim Children gave two types of justifications:

Repeating of the given statement The stronger statement

Even in cases when they gave the right answer, the children had wrong justifications (rougly 70% of the justifications for the scale <all, some> were of the first type)

Experiment 2

Subjects: a set of 30 children (distinct from the first set)

Children were trained to recognize pragmatic anomaly

The stories that described the situations were modified to focus on the performance of the principal character

Experiment 2, Results

Children could reject the weak statements reliably better:52% <all, some> (previously 12%)47.5% <finish, start> (previously 10%)90% <three, two> (previously 65%)

When children are more logical than adults: experimental investigations of scalar implicature

Author: Ira A. Noveck

Presenter: Ovidiu Fortu

Objectives

Study the scalar implicatures experimentally

Establish that scalar implicatures are psychologically real and common in reasoning scenarios

Establish how this class of weak scalar terms develops

Three sets of experiments

Experiment 1 – modal “might” (when it is comparable with “must”)

Experiment 2 – a follow up of experiment 1; designed to determine the extent to which the scalar implicature can be suspended

Experiment 3 – investigates weak claims based on the “some” quantifier

Experiment 1

Subjects: 32 5-year olds, 20 7 year olds, 16 9 year olds, 20 adults (all native English speakers)

Set-up: two open boxes, one with a parrot and one with a parrot and a bear

A puppet then states 8 claims: (1) There has to be a parrot in the box (true); (2) There does not have to be a parrot in the box (false); (3) There might be a parrot in the box (true); (4) There cannot be a parrot in the box (false); (5) There has to be a bear in the box (false); (6) There might be a bear in the box (true); (7) There does not have to be a bear in the box (true); (8) There cannot be a bear in the box (false)

Experiment 1, Results

Is the statement of the puppet true? Necessary conclusion (parrot)

Has to be a parrot Yes 75% 90% 88% 100% Does not have to be a parrot No 72% 75% 75% 100% Might be a parrot Yes 72% 80% 69 35 Cannot be a parrot No 66 80% 100% 100% Total 73% 81% 83% 83%

Possible conclusion (bear) Has to be a bear No 47 65 88% 100% Does not have to be a bear Yes 66 75% 81% 100% Might be a bear Yes 53 80% 100% 100% Cannot be a bear No 53 80% 100% 100% Total 55 75% 92% 100%

Experiment 3

The results and setup were very similar to the ones in previous paper

The tests with older subjects showed better results – more than 85% for 7-year olds; 10 year olds had performance comparable to adults

Children have more problems with this scale (in one test only 6% rejected all weak claims)

Conclusions

Ability to communicate using pragmatics is developed later in the growth

Implicatures are difficult to infer, requiring more experience