Memory

All learning requires memory Three stages of memory phenomena

Acquisition Retention Retrieval

Taxonomy of Human Memory

Procedural Declarative

Working and Reference Memory

Episodic and Semantic Memory

Motor Skills

Classical Conditioning

Operant Conditioning

automatic, incremental,unconscious

effortful,conscious

Reference versus Working Memory

• Reference memory– long term retention of events, relationships, and

procedures– associations, rules, skills.

• Working memory- short term retention, typically relevant only to the current trial, includes information retrieved

Working Memory in Animals

Hunter (1913)

food

Working Memory or Body Orientation?

food

Delayed Matching to Sample (DMTS)

SampleComparison Comparison

Delayed Matching to Sample (DMTS)

PECK

FOOD

PECK

NOFOOD

Symbolic Matching to Sample

Symbolic Matching to Sample

PECK

FOOD

PECK

NOFOOD

NOFOOD FOOD

What is Learned in DMTS?

a) General Matching RulePigeon = No! (with few samples)Cumming & Berryman (1965)

- Trained on Red, Green, Blue- Failed to transfer to Yellow

b) Specific “If-Then Rules”Symbolic Matching-To-Sample

- Learned as rapidly as Standard DMTS

Memory Coding

a) Retrospective = Backward Looking

b) Prospective = Forward Looking

Retrospective Code: IF , Remember

Prospective Code: IF , Remember

Roitblat, 1980

Confusion Errors? 1. between samples 2. between comparisons

Confusions:Comparisons > Samples

Therefore: Prospective Coding

Serial List Learning

Present list of items to subject one at a time

A B C D E F

Recall in any order

Ask subject to recall or recognize a single item

A B C D E F

Acc

ura

cy

Primacy effect Recency effect

Serial List Learning

Humans:

Testing after a delay produces a primacy effect

A B C D E F

Acc

ura

cy

Testing immediately after list produces a recency effect

A B C D E FA

ccu

racy

What about in other animals?

Radial Arm Maze

How Solved? Random Choice Odour Trail Patterned Responding Memory*

12-Arm Radial Maze

Choices Prior to First Error

0

2

4

6

8

1 3 5 7 9 11 13

Trial

Mea

n C

ho

ices

12-Arm Radial MazeTotal Number of Errors

0

2

4

6

8

10

1 3 5 7 9 11 13

Trial

Mea

n E

rro

rs

Can rats switch from retrospective to prospective memory?

12

11

3

2

1

9

10

6

5

4

7

8

Cook et al. (1985)

Rats removed after making 2, 4, 6, 8, or 10 choices

Shifting from retrospective to prospective midway produces the lowest memory load (inverted U-shaped error curve)

Cook et al. (1985)

RememberPlaces Visited

RememberPlaces Not Visited

Memory Coding

a) Active = rehearse relevant information

b) Passive = gradual fading of a memory trace

Human Forgetting Curve With No Rehearsal

Pigeon Forgetting Curve

Roberts, 1972

Directed Forgetting

ITI

Sample

Comparisondon’tpeck

peck

Remembercue

Forgetcue

peck peck peck

Forgetcue

Delay

Least More Most

Human Reference Memory Duration (relatively long-term) Capacity (relatively large) Forgetting (details lost, gist remembered) Requires Consolidation

Retention of Fear Conditioning

Clark’s Nutcracker

Food Storing Bird About 5,000 Caches 20 x 20 KM Area 9-month Buried Under Snow

Sarah Shettleworth

Results Birds recovered previously cached seeds and

made few errors Didn’t find seeds hidden by experimenter Didn’t return to the same site if first storing

episode is followed by a second storing episode

Summary of Animal Memory

Working Memory

Prospective and Retrospective

Active and Passive

Reference memory

Duration and Capacity

Forgetting and Consolidation

Do Animals have Episodic Memory?

Episodic Memory Conscious Recollection Dated Personal Memory (what, when, and where)

Western Scrub-Jay (Nicola Clayton)

Clayton’s Results

Metamemory in Rats? Knowledge of the state of one’s own memory

for example, memory strength Foote and Crystal (2007)

Duration of noise sample, 2.00 to 3.62 = Left Duration of noise sample, 4.42 to 8.00 =Right Choice to continue → memory test, large reward Choice to bail-out → no test, small reward

Foote and Crystal (2007) Procedure

Foote and Crystal (2007) Results

Problems Only 2 of 3 rats showed positive results (5

others always bailed or always decided) Maybe they learned to bail with feedback on

the “close” duration values?