How are sentences stored in LTS?

Explicit tasks; episodic memorySachs (1967)

STUDY subjects hear a story

“…A wealthy manufacturer,Matthew Boulton, sought outthe young inventor…”

TEST yes-no recognition

correct response(1) identical sentence yes(2) change form, but not no meaning (formal)(3) active/passive change no(4) semantic change no

ONLY (4) CHANGES MEANING

Sachs Results

You forget the form of the sentence, butremember the meaning

FalseAlarms

immediate 80 syllableslater

160 syllableslater

| | |

10%

50%

Test is

FormChange

Active/Passive

SemanticChange

In STS, you remember the actual words of thesentence.

In LTS, you remember the meaning, but forgetthe wording.

False Alarm Method

Try to get subjects to make a false alarm on a yes-no recognition test

It shows what part of the episode they remembered and what part they forgot

e.g., in Sachs (1967), false alarms to items withsame meaning, but different wording

Sentences in LTS are stored as propositions

Ratcliff & McKoon (1978)

Study list of sentences...

“The geese crossed the horizon as the wind shuffledthe clouds.”

.

.

.

1. CROSS (GEESE, HORIZON)

2. SHUFFLE (WIND, CLOUDS)

3. AS (1,2)

Predict horizon “closer” togeese than to wind

Item recognition priming test

“clouds” “yes”“chair” “no”

.

.

.“geese” OR “wind” “yes” PRIME“horizon” “yes” TARGET

RT to horizonwhen geese is prime when wind is prime

600 msec 630 msec

Why?

Either because GEESE is closer to HORIZONin sentence (surface structure)

Or because GEESE and HORIZON are in the same proposition (propositional hypothesis)

STUDY“The kitten that the girl was carrying scratched the lawyer”

SCRATCH (KITTEN1, LAWYER1)CARRY (GIRL1, KITTEN1)

TEST (item recognition priming)

PRIME “kitten” “girl”

TARGET “lawyer” “lawyer”

Integration Hypothesis

Propositions that contain the same conceptsconnect together in memory

Example:“A car hit a tree. The tree fell on a wire,

and the wire touched another car.”

HIT (CAR1, TREE1)FALL-ON (TREE1, WIRE1)TOUCH (WIRE1, CAR2)

Car Tree Wire

Concepts already in semantic memory

Tree1Car1

Car2

Wire1

is isis

is

hit fall on

touch

Tree1Car1 Wire1

is isis

hit fall on

Tree1Car1

is is

hit

Based on Bransford & Franks (1971)

Actually presented“The tree shaded the man who wassmoking a pipe”

Never presented (but consistent)“The tree in the front yard shadedthe man”

Never presented (inconsistent)“The tree broke the window”

frontyard

tall

tree

man pipesmoked

in

shad

ed

is

Support for integration hypothesis

Bransford & Franks (1971)

McKoon & Ratcliff (1980)

“The lawyer gestured to a waiter.”

The waiter brought coffee.

The coffee stained the napkins.

The lawyer flourished documents.

The documents explained a contract.

The contract satisfied a client.

Propositions

GESTURE TO (LAWYER1, WAITER1)...etc.

Document1

Client1

Contract1

Lawyer1

Waiter1

Coffee1

Napkins1

is is is

is

is is is

gesture

to

NapkinsCoffee

Document Contract Client

Lawyer

Waiter

Nodes for Conceptsalready in semantic memory

is is is

is

is is is

Document to Waiter = 2 linksDocument to Napkins = 4 links

Prediction“waiter” primes document more than “napkins” does

Recognition Test

client

pen

lawyer

sofa

waiter OR napkins

documents

PRIME

TARGET

RT to say “yes” to documents

665 msec with waiter as prime

704 msec with napkins as prime

Supports integration hypothesis

“Sally likes pets. She has a black cat.”

LIKES (SALLY, PETS)HAS (SALLY, CAT1)IS (CAT1, BLACK)

humans pets

mice

cats dogs bones

keepchase

like

areare

chase

Sally

likesis

Sally

cat1

likes

has

is

is

Sally

cat1

black

likes

has

is

is

is

Directly stated propositions and inferences

“Sally likes pets. She has a black cat.”

Directly-stated

SALLY HAS A CAT

Inferences

Propositions that follow from thedirectly-stated propositions or from other inferences

SALLY LIKES CATS

(1) Logical inferences

necessarily follow from directly-stated propositions

e.g., Sally has a petSally’s cat is a mammal

(2) Pragmatic inferences

are probably true, but notnecessarily true

e.g., Sally takes good care ofher cat

Sally buys cat food

Inferences in Real Life

Commercials

“Four out of five doctors recommendthe ingredients in Anacin”

Court Room

Harris, Teske & Ginns (1975)

Witness: “I went up to theburglar alarm”

Memory test“Did the witness say that they rang theburglar alarm?”

Nearly everyone said “yes” even when instructednot to draw inferences

Turtles ExperimentBransford, Barclay & Franks (1972)

Group 1

“Three turtles rested beside a floating logand a fish swam beneath them.”

“Three turtles rested beside a floating logand a fish swam beneath it.”Result: very few false alarms

Group 2

“Three turtles rested on a floating logand a fish swam beneath them.”

“Three turtles rested on a floating logand a fish swam beneath it.”Result: many false alarms!

STUDY

TEST

STUDY

TEST

Group 2 propositions

Conclusion:Memory contains inferences as well as

directly stated propositions

Inference added to memory:causes false alarms to testsentence with fish swimmingbeneath log

floatinglog

3turtles

fishsw

im ben

eath

rest on

swim

ben

eath

Schemas

An organized set of propositions that describesthe general characteristics of some thing oractivity. (Stored in semantic memory)

Restaurant Schemaroles: CUSTOMER SERVER

(human) (human)

1. ENTER (CUSTOMER, RESTAURANT)2. SIT-AT (CUSTOMER, TABLE)3. GREET (SERVER, CUSTOMER)4. .

.

. BRING (BILL, TO CUSTOMER, BY SERVER) PAY (CUSTOMER, BILL) LEAVE (CUSTOMER, RESTAURANT)

Other examples:Quiz show, coins

Restaurant Schema

Restaurant

Order

Menu

Table

Customer

Human

Waiter

1

5

4 3

2

6

is isenters

in

pick

s up sits at

takes

goes

to

looks for

Schemas and Inferences

Schema Instantiation Inferences -propositions that link concepts in a text toconcepts in a schema

TEXT: “John went to the White Horse”“He sat down . . “

Restaurant SchemaJohn

WhiteHorse

restaurantcustomer

go to go to

is

is

Schema instantiation inferencesIS (JOHN, CUSTOMER)IS (WHITE-HORSE, RESTAURANT)

How memory and comprehension fail when youdo not make schema instantiation inferences.

Bransford and Johnson (1972)

“Clothes washing” experiment

Recall(number of

“ideas”)

Ratedcomprehension(1-7 pt. scale)

No titlegiven

2.8

2.3

Title givenbefore reading

5.3

4.5

If you don’t know it’s about clothes washing, you can’t connect the text to your clothes washing schema.

Bridging Inferences

Inferences that fill gaps in the text by usinginformation from a schema.

“John went to the White Horse.He ate and left.”

Inference JOHN PAID HIS BILL

Restaurant SchemaWhiteHorse

John

some-thing

restaurantcustomer

bill

ate

go to

leftgo to

pays

is

is

McKoon & Keenan (1974)

Investigation of Memory for Bridging Inferences

Read“A camper carelessly threw a match.A great forest was destroyed.”

Destroyed

Match1

Camper1

Great

Forest1

threw

was

BridgingInferencemade byconsulting“forest fire”schema

Fire1

burn

start

True-false Test

Directly-statedA great forest was destroyed.

T or F ?

InferencesThe match started a fire.

T or F ?

RTto say“true”

immediatetest

20 minuteslater

inference

directly-st

ate

Conclude:Inferencestoredin LTS

‘Nancy’ Experiment

Owens, Bower & Black (1979)p.355 in text

Nancy arrived at the cocktail party. She

looked around the room to see who was there.

She went to talk with her professor. She felt she

had to talk to him but was nervous. … Nancy

went over to the refreshments. The hors

d’oeuvres were good but she wasn’t interested in

talking to the rest of the people. ….

Nancy woke up feeling sick again and

wondered if she was pregnant. How would she

tell the professor she was seeing?…

Nancy Experiment

Recall Results

Directly-statedPropositions

Inferences(Nancy got sickat the party)

withtheme29.2

15.2

withouttheme20.2

3.7

•Schema improves memory for directly-statedproposition

•It also promotes recall of inferences which werenever mentioned

Childhood Amnesia

Recall

birth now

serial position for your whole life

Repression? (Freud’s theory)

Language acquisition?

Difference between infant and adult schemas?

Waldvogel (1948)n

um

ber

of

mem

orie

s

14 -

12 -

10 -

8 -

6 -

4 -

2 -

| | | | | | | | 0 1 2 3 4 5 6 7

Recall yourchildhoodmemories

femalesmales

Sheingold & Tenney (1979)

Asked questions about birth of younger sibling.

Answers confirmed by parents.

accuracyscore

| | | | |1-2 3-4 5-6 7-8 9+

Age

No memories before 3

Do animals show “childhood” amnesia

frogs yes

guinea pigs no

Rats yes

May depend on how “advanced” animal is at birth

Stoloff & Spear (1976)

15-day old rats (still infants)36-day old rats (young, but not babies)

Traineduntilperfectin T-maze

correctturn

shock

Older rats forget what they knew as babies

training 1-daylater

21-dayslater

100%

chance

36-day olds

15-day olds

Tested 1 day later and 21 days later

Conclude

Little evidence for repression explanation

Language may play a role (but only in humans!)

Schema Explanation

Schemas for early memories aredifferent than those for adults

can’t consciously access them

Earlysensory-motor

schemas

Laterproposition

schemas

The effects of schemas on judgment

Hindsight Bias

The outcome of an uncertain situation is judged

to be more likely if you already know what

happened.

Rochester Nuke Plant Case

Hindsight bias in assigning blame in accident

steam tube

reactorcore

tools

Experimental Demonstrations of Hindsight Bias

Fischoff (1975)

•subjects read about war between British andGurkas•then they judge the likelihood of the waroutcome

Told nothing(no hindsight)

Told “Britishactually won”

Told “Gurkasactually won”

Britishwin

.40

.55

.32

Gurkaswin

.20

.12

.35

Nobodywin

.40

.33

.33

Estimated Probability

Arkes et al. (1981)

Doctors given a case history to read

Is it disease A or disease B?

Group 1 - told nothing about real diagnosis

Group 2 - told “correct” diagnosis was disease A

Group 3 - told “correct” diagnosis was disease B

Result: probability estimates were higher for

“correct” diagnosis

So: Hindsight Bias

•Hindsight bias happens when you warn people

to avoid it

•It does not happen when subjects don’t believe

the outcome information

Explaining Hindsight Biases by Schemas

•Outcome info activates schema

•Schemas guide retrieval of facts

•Retrieved facts bias judgments of probability

Medical example: heart attack or indigestion

Symptoms

smokes

felt pain after dinner

skipped heart beats

burps a lot

heartattack

schema

indigestionschema

Mnemonic Devices

External Aids -- notes, string . . .

Internal Aids

used at used atencoding retrieval

Internal Aids used at Encoding

Basic Strategy

make each item distinctive(reduce interference)

make a collection of items meaningfully related(instantiate a schema)

use a retrieval strategy to make sure you don’t miss anything

Method of loci

used for serial recall makes items distinctive and allows for a good

retrieval strategy

Peg words

serial recall distinctive good retrieval strategy

one - buntwo - shoethree - treefour - doorfive - hivesix - sticks

seven - heaveneight - gatenine - wine

ten - zen

Keyword method for foreign language vocabulary

Paling (Dutch) = Eel (English

make image of

Emphasizes distinctiveness and useful retrievalstrategy

Chunking Strategies (for lists)BROWN EEL NAIL PAPER

sentencestoryimage

Emphasize distinctiveness and meaningfulnessof collection

People with Good Memories

Exceptional ability or just good strategies?

How specific are the abilities

S. (studied by Luria)

had very vivid mental imagery

serial recall of 70-word listsretained for years

used method of loci

An exceptional memory with no imagery

V.P. (studied by Hunt & Love)

Continuous Paired Associate Task

JUK - 23

ROQ - 29

CUH - 13

JUK - ?

CUH - 97

ROQ - ?

CUH - ?

etc.VP’s digit span = 25Story recall - nearly perfect

after 1 year

•Used rapidly generated semantic associations

Recall

100%

| | | | | |2 4 6 8 10 12

VP

CollegeStudents

Lag

No mnemonic devices at all

Elizabeth (Stromeyer

Eidetic Memory“Photographic”

10,000 dotsResults are questionable

Conclusions

•People don’t just have good or bad memory

as a whole -- they have good or bad memory-

related skills.

(e.g., good imagery, good ability to form

semantic associations)

•For verbal memory, mnemonic devices are

needed for exceptional performance, but these

don’t need to involve imagery.

THE CAR CLIMBED THE HILL.

THE CAR CLIMBED THE HILL.