Long-term Memory Encoding and retrieval. Long-term memory Basically includes anything retained that did not occur few moments earlier Source of information.

Long-term Memory

Encoding and retrieval

Long-term memory

Basically includes anything retained that did not occur few moments earlier

Source of information that does not come from the environment

Learning Storage of information in memory as a

consequence of experience Process of acquiring new associations

among stimuli, responses and outcomes.

What is Learned? How is it Learned?

Associative theories Cognitive theories

Classical Conditioning Characterized by the generalization

of a fixed or previously learned behavior

Responses are elicited from Stimuli Some terminology

Unconditioned Stimulus Unconditioned Response Conditioned Stimulus Conditioned Response

Some terminology Unconditioned stimulus (US)

Elicits a response without training Shock

Unconditioned Response (UR) Elicited without training by a (US) Smacking whoever gave you the shock

Conditioned Stimulus (CS) That which through training elicits a particular

response Pretty flowers

Conditioned Response (CR)* Response to the conditioned stimulus Smacking whoever gives you pretty flowers

Or conditional, as Pavlov originally meant.

Properties of Classical Conditioning Acquisition

Process of acquiring CS-CR association Extinction

If CS is presented without US then the CR will eventually become extinct

Generalization The degree to which an individual will respond to a

similar (but not identical) CS Discrimination

The process of reducing generalization Eliciting a specific CR to a specific CS

Factors that affect Classical Conditioning

The Laws of Association Contiguity Frequency Intensity

Factors that Affect Classical Conditioning

Contiguity Temporal relation of the stimuli

Time between and order of the CS & US Conditioning is best when the CS precedes and

continues in the presence of the US

Factors that Affect Classical Conditioning Contingency

CS must meaningfully predict the US Functional relation between CS and US However… there is superstition.

Must at least seem meaningful Preparedness

Biopreparedness – organisms are "biologically prepared" or "genetically tuned" to develop certain conditioned associations

Such a system of learning has adaptive value, and such predispositions can aid survival

Prior experience Blocking

Examples of Applications of Classical Conditioning

Systematic Desensitization Counterconditioning Pairing unpleasant stimuli with

pleasant in hopes of reducing response to unpleasant stimuli

Aversion Therapy Associating fear stimuli to some

undesired behavior in order to eliminate it

Clockwork Orange: Violence and nausea

Operant conditioning B. F. Skinner

Look! It’s grandpa and he’s come to take your free will away!

Operant / Instrumental Conditioning

Based on the principle of reinforcement What is reinforced? What is reinforcing?

Development of associations between particular responses and consequences of the response (outcomes).

Thordike’s Puzzle Box See how long it takes for a cat to ‘figure it

out’ Takes a long time at first… But eventually will escape Takes less time the next go around, and

after that Law of effect

“Of several responses made to the same situation, those which are accompanied or closely followed by satisfaction to the animal will, other things being equal, be more firmly connected with the situation, so that, when it recurs, they will more likely recur… The greater the satisfaction… the greater the strengthening… of the bond.

Basic Mechanisms of Operant Conditioning

Behaviors have consequences. Consequences are contingent on

behaviors. Organisms adapt behavior to match

contingencies. Consequences usually satisfy a “drive”

Biological need Motivational need (bio+attractiveness) Well-being of individual

Consequences of Behavior Reinforcement or Punishment

Reinforcement Consequences of behavior increase the

probability of response (behavior)

Punishment Consequences of behavior decreases

the probability of response

Reinforcement and Punishment

Both Reinforcement and Punishment can be positive or negative

Positive – presentation of stimuli Negative – removal of stimuli

The result is a table of contingencies.

Reinforcement and Punishment

Response

Stimulus

Increase (rein.) Decrease (pun.)

Apply a stimulus (+)

Remove a stimulus(-)

Positive Reinforcement

(reward)

Positive Punishment

(punishment)

Negative Reinforcement

Negative Punishment

(omission)

Properties That Affect the Level of Conditioning

Quality of the Reinforcer Amount of Reinforcer

Food Money

Better Quality Reinforcer Taste of food

Experience with Other Reinforcers Contrast Effect

Change the quality/quantity of the reinforcer during the course of conditioning

Condition a rat to run the T-maze with 1.0 gram of food.

Next few trials use only 0.5 gram of food. Rat slows running.

Properties That Affect the Level of Conditioning

Strength of Drive Satisfaction of Drive

Most lab participants are deprived before conditioning begins.

Motivation How might the behaviorist explain

intrinsic motivations? Maybe this particular rat just fancies

running in mazes?

Properties That Affect the Level of Conditioning

Reinforcement Contingencies Continuous Reinforcement

A response always yields reinforcement Most rapid conditioning Not long-term conditioning

As soon as reinforcement is removed, response rapidly declines

Partial Reinforcement Response sometimes yields reinforcement Slower learning than continuous

reinforcement Long-term learning

Schedule of Reinforcement Fixed

Every N responses/time yields reinforcement Variable

Response-Reinforcement contingency changes over the course of Conditioning

Ratio Reinforcement is based on the number of responses

Interval Reinforcement is based on passage of time

Examples Fixed ratio: free coffee at jazzman’s Variable ratio: slot machine Fixed interval: checking mailbox Variable interval: checking email

Concept of Association Associations from conditioning represent predictive

probabilities of functionally relevant (meaningful) events.

Predictive Probability is defined as the Strength of Association

Strength of Association follows the Power Law

Power Law

Associative strength is a product of …

Str

engt

h

# of Pairings

Power Law

Number of positive pairings divided by the number of negative pairings CS Alone US Alone or with other CS Response with no reinforcement

The relative contributions of contextual strength to background strength Acquired strength vs. Background experience

Repetition

Associative Learning Accounts for certain types of memory

phenomena Memory Structure Highly practiced information Habitual responses Stimulus generalization

Assumes memory mechanism is the same as associative mechanism (single system)

Associative Memory Associative memory theory alone cannot

account so well for other phenomena Free Recall

No cue Subjective organization

Von Restorff Effect Effect of stronger memory for a salient item in a series

Sensory Memory “Direct” memory of sensory information Short-term representations No Practice

Complexity of language acquisition/production Systematic memory distortions

Beyond association Although simple associative mechanisms described

by classical and operant conditioning may account for some aspects of learning, more was needed

Subtle shift from learning theories to theories of memory, which emphasized knowledge representation in an information processing system

Focused on encoding and retrieval processes to help explain memory performance in a variety of settings

Levels of Processing Encoding specificity Transfer appropriate processing

Basic Mechanisms of Memory Encoding

Acquisition of Information “Learning” ?

Maintenance Retaining information

Retrieval Using information

How do the processes of Encoding and Retrieval influence what is remembered?

Levels of Processing Craik & Lockhart (1972)

Formalized the notion of “depth” of processing and demonstrated how it affects memory.

There are “depths” to which information can be processed

Shallow: encoding information in terms of its physical or sensory characteristics

Deep: encoding information in terms of meaning Levels (for words)

Structural Is it all caps? Shallow

Phonetic Does it rhyme with _?

Semantic Is it an animal? Deep

Levels of Processing Craik & Tulving (1975) Incidental memory task (Ss unaware a

memory test was coming) 3 processing tasks

Case: Is the word in capital letters? BOOK

Rhyme: Does the work rhyme with fate? LATE

Sentence: Does the word fit the sentence: He met a __________ in the pub?

FRIEND

Levels of Processing

Results

Pro

port

ion

corr

ectl

y re

cogn

ized

0

100

CAPS? Rhyme? Sentence?

Levels of Processing Rogers, Kuiper, & Kirker (1977) Presentation

40 Adjectives 4 blocks of 10 adjectives

In each block, participants performed different encoding tasks for each adjective.

Is it in CAPITAL letters? Does it rhyme with X? Is it a synonym of Y? Does it describe you?

Test Incidental recall task

Rogers, Kuiper, & Kirker (1977)

People tend to recall more information when they relate the information to themselves.

The concept of self has a rich and organized set of internal cues to which information can be associated (Belezza, 1984).

Mea

n R

ecal

l

0

10

CAPS? Rhyme? Synonym? You?

Levels of Processing Such results suggests that deeper levels of processing produce more

permanent retention than shallow levels of processing.

Distinctiveness and elaboration may be responsible for the effectiveness of deep levels of processing

The self-reference task encourages especially deep levels of processing, resulting in enhanced memory. Self-reference instructions may encourage greater organization, and the self may serve as a rich source of associations.

Other results Intention to learn does not change LOP pattern of results (Hyde & Jenkins,

1973) Generation effect (Slamecka and Graf, 1978)

Problem: What is “deep” and what is “shallow?” Circular logic If processing is deep then retention will be better. If retention was better, then processing must have been deeper. There is no precise way to measure ‘depth’

Perspective Perspective

The purpose of encountering information influences what information is encoded.

Anderson & Pichert (1978) Had people listen to the description of a

house Gave participants different perspectives

(roles) for considering the description Home Buyer Burglar

Analyzed the proportion recalled of target items from different perspectives

Identity

Items

Pro

port

ion

Reca

lled

Recall #1

Perspective

Distracter task, then switch perspectives and try to recall again

Items

First identity/second identity

Change in p

roport

ion

reca

lled

Perspective

Perspective Had people switch perspective and they could

then recall info they previously had not. Perhaps the perspective serves as a selection

criteria at retrieval. So memory performance depends on …

How something is encoded And the purpose for which it is retrieved.

Information is remembered best if it is retrieved in a manner that is consistent with which it was encoded

Encoding Specificity Principle Transfer-Appropriate Processing

Encoding Effects

Encoding-Specificity Principle Information is

available to the extent to which retrieval matches encoding

Tulving and Thomson, (1973)

Step 1: Study List (with weak associates as cues)

head LIGHT

bath NEED

pretty BLUE

grasp BABY

whiskey WATER

cabbage ROUND

spider BIRD

glue CHAIR

Tulving & Thomson

Step 2: Free-association (to strong cues of TBRs)

dark night light black room

want need desire wish get

sky sun cloud blue open

infant child mother love baby

lake water smooth river ocean

square round flat circle corner

eagle eye mountain bird high

table chair desk lamp top

Tulving & Thomson

Step 3: Recognition test for associations

dark night light black roomwant need desire wish getsky sun cloud blue openinfant child mother love babylake water smooth river oceansquare round flat circle cornereagle eye mountain bird hightable chair desk lamp top

Tulving & Thomson

Step 4: Cued-recall test (weak associates as cues)

head _______

bath _______

pretty _______

grasp _______

whiskey _______

cabbage _______

spider _______

glue _______

Tulving & Thomson

Tulving & Thomson

One would expect that any item recalled in phase 4 would also have been recognized in phase 3 (because recall involves recognition stage)

This was not the case - 59% of items were recalled, 22% of initial list words generated were recognized

Tulving & Thomson Why? The first stage established the

association between cue and target The recognition test did not match the

encoding context Targets were now associated with other

words In the recall stage, the context matched

the encoding phase

Morris, Bransford, & Franks (1977)

Had people make one of two judgments at presentation

Shallow: Rhyming (Does it rhyme with hat?) Deep: Semantic (Does it have a tail?)

Two test conditions Recognition Rhyming

“Hat” “Did you see a word that rhymes with X?”

Test Condition either matched or mismatched original encoding

Morris, Bransford, & Franks

Rhyme

Rhyme

Semantic

Recognition

TEST

PR

ES

EN

TA

TIO

N

++-

-

Morris, Bransford, & Franks

LOP effect for standard test.

But opposite for rhyming test

Deep processing does not always enhance memory

Transfer Appropriate Processing Memory performance depends on the extent to which

processes used at the time of learning are the same as those used when memory is tested.

LOP approach assumed that semantic processing was always superior to non-semantic processing

The transfer appropriate processing approach demonstrates that a form of encoding which is “shallow” for one purpose might be “deep” for another.

Conclusion Memory not just a function of depth of processing Depends also on the match between encoding processes

and type of test

Interaction of Encoding and Retrieval

Context Congruency Godden & Baddeley

Divers memorized a list of words Half learned the words on dry land Half learned words underwater Tested either on dry land or

underwater

Interaction of Encoding and Retrieval

Recap

LEVELS OF PROCESSING emphasizes operations at encoding semantic/elaborative processing better for LTMENCODING SPECIFICITY emphasizes that information about retrieval

cue must be encoded at study for cue to be effective

TRANSFER APPROPRIATE PROCESSING memory best when processes at test match

processes used at study

*For another view, see Nairne, 2002

Different Methods of Retrieval What is your name?

Automatic What is the Capital of Australia?

Generate & recognize What are you doing next Tuesday at 1200?

Schema + Search What is the layout of your house?

Spatial Is “FLORB” a word?

Direct access What was Beethoven’s telephone number?

Knowledge

Basic Mechanisms General Principles of

Memory Strength

Background Contextual

Congruity Between encoding

and retrieval Organization

Distinctiveness Segregate item in

memory Spacing

Massed vs. Distributed

Recency and Primacy

Spacing Old rule: Spacing

learning enhances recall

Bahrick family and foreign language learning

Spacing

Why does it work? Varying encodings may lead to

more associations Reminds of earlier presentation, so

may reinforce earlier learning (perhaps increasing baseline activation)

Recency and Primacy

Demonstrated in the serial-position curve

Learn a list of items in order… ..and reproduce the list in order

Recency and Primacy Serial-Position Effect

Position in List

Pro

port

ion

Rec

alle

d

0

100

Beg. Mid. End

Recency and Primacy Primacy

Memory advantage for items initially encountered.

Rehearsal? Distinctiveness?

Recency Memory advantage for items recently

encountered. Working memory?

Retrieval Many different theories about how retrieval takes place.

Information Processing Theories Modal Model, LOP, TAP

Associative Theories ACT-R, TODAM

Search Models SAM, REM

Trace Theories Perturbation Model

Connectionist Models PDP, EPIC

Biological-Based Theories HERA, CARA

Retrieval Differ… What and how information is retrieved.

Veridical representation Or translation

Memory trace Reconstruction

Share… Emphasis on information available at retrieval.

Cues Partial information Contextual information

Something guides retrieval. Memory as a Decision