StorageStorageChapter 8, Lecture 3Chapter 8, Lecture 3

“So, despite the brain’s vast storage capacity,we do not store information as libraries storetheir books, in discrete, precise locations.”

- David Myers

Storage: Retaining Information

Storage is at the heart of memory. Three stores of memory are shown

below:SensoryMemory

WorkingMemory

Long-termMemory

Encoding

RetrievalEncoding

Events

Retrieval

Sensory Memory

SensoryMemory

WorkingMemory

Long-termMemory

Encoding

RetrievalEncoding

Events

Retrieval

Whole Report

The exposure time for the stimulus is so smallthat items cannot be rehearsed.

R G TF M QL Z S

50 ms (1/20 second)

“Recall”R T M Z

(44% recall)

Sperling (1960)

Partial Report

Low Tone

Medium Tone

High Tone

“Recall”J R S

(100% recall)

Sperling (1960) argued that sensory memory capacity was larger than what was originally

thought.

50 ms (1/20 second)

S X TJ R SP K Y

Time Delay

“Recall”N _ _

(33% recall)

TimeDelay

50 ms (1/20 second)

A D IN L VO G H

Low Tone

Medium Tone

High Tone

Sensory Memory

The longer the delay, the greater the memory loss.

20

40

60

80

Perc

en

t R

ecog

niz

ed

0.15 0.30 0.50 1.00

Time (Seconds)

Sensory Memories

Iconic0.5 sec. long

Echoic3-4 sec. long

Hepatic< 1 sec. long

The duration of sensory memory varies for the different senses.

Working Memory

SensoryMemory

WorkingMemory

Long-termMemory

Encoding

RetrievalEncoding

Events

Retrieval

Working Memory

Working memory, the new name for short-term memory, has a limited capacity

(7±2) and a short duration (20 seconds).

Sir George Hamilton observed that he could accurately remember up to 7 beans thrown on the

floor. If there were more beans, he guessed.

Capacity

You should be able to

recall 7±2 letters.

The Magical Number Seven, Plus or Minus Two: Some Limits on

Our Capacity for Processing Information

(1956).

George Miller

M U T G I K T L R S Y P

Ready?

Chunking

F-B-I-T-W-A-C-I-A-I-B-M

The capacity of the working memory may be increased by “chunking.”

FBI TWA CIA IBM

4 chunks

Duration

Peterson and Peterson (1959) measured the duration of working memory by

manipulating rehearsal.

CH??

The duration of the working memory is about 20 sec.

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Working Memory Duration

Long-Term Memory

SensoryMemory

WorkingMemory

Long-termMemory

Encoding

RetrievalEncoding

Events

Retrieval

Long-Term Memory

Essentially unlimited capacity store.

The Clark’s nutcracker can locate 6,000 caches ofburied pine seeds during winter and spring.

R.J. E

rwin/ Photo R

esearchers

Memory Feats

Memory Stores

FeatureSensoryMemory

Working Memory

LTM

Encoding Copy Phonemic Semantic

Capacity Unlimited7±2

ChunksVery Large

Duration 0.25 sec. 20 sec. Years

Storing Memories in the Brain

1. Loftus and Loftus (1980) reviewed previous research data showing, through brain stimulation, that memories were etched into the brain and found that only a handful of brain stimulated patients reported flashbacks.

2. Using rats, Lashley (1950) suggested that even after removing parts of the brain, the animals retain partial memory of the maze.

Synaptic Changes

In Aplysia, Kandel and Schwartz (1982) showed that serotonin release from

neurons increased after conditioning.

Photo: Scientific A

merican

Synaptic Changes

Long-Term Potentiation (LTP)

refers to synaptic enhancement after

learning (Lynch, 2002). An increase in

neurotransmitter release or receptors on the receiving neuron

indicates strengthening of synapses.

Both P

hotos: From

N. T

oni et al., Nature, 402,

Nov. 25 1999. C

ourtesy of Dom

inique Muller

Stress Hormones & MemoryHeightened emotions (stress-related or otherwise) make for stronger memories.

Flashbulb memories are clear memories of emotionally significant moments or events

Scott Barbour/ G

etty Images

Beryl Benderly has described “flashbulb”memories this way: “It’s as if our nervoussystem takes a multimedia snapshot of thesounds, sights, smells, weather, emotionalclimate, even the body postures we experienceat certain moments.”

In a sentence or two, write down yourIn a sentence or two, write down yourthree most vivid memories…three most vivid memories…

A car accident you were in or witnessed (85)When you first met your college roommate (82)Your high school graduation (81)Your senior prom (78)An early romantic experience (77)A time you had to speak in front of an audience (72)When you got your admissions letter from college (65)The day President Reagan was shot in Washington (52)Your first flight (40)The moment you opened your SAT scores (33)Your seventeenth birthday (30)The last time you ate a holiday dinner at home (23)Your first college class (21)The first time your parents left you alone at home (19)Your thirteenth birthday (12)

The percentage of Duke students who had flashbulbrecollections of each event:

Storing Implicit & Explicit Memories

Explicit Memory refers to facts and experiences that one can consciously know and declare. Implicit memory involves learning an action while the

individual does not know or declare what she knows.

p. 343

Hippocampus

Hippocampus – a neural center in the limbicsystem that processes explicit memories.

Weidenfield &

Nicolson archives

No New Memories

Anterograde Amnesia

AnterogradeAmnesia

(HM)

Surgery

After losing his hippocampus in surgery, patient Henry M. (HM) remembered

everything before the operation but cannot make new memories. We call this

anterograde amnesia.Memory Intact

Different from retrograde amnesia, which is loss of memory from before an event or

injury.

Implicit Memory

HM learned the Tower of Hanoi (game) after his surgery. Each time he plays it, he is unable to

remember the fact that he has already played the game.

HM is unable to make new memories that aredeclarative (explicit), but he can form newmemories that are procedural (implicit).

CBA

CerebellumCerebellum – a neural center in the hindbrain

that processes implicit memories.

HomeworkRead p.345-349

“At any given moment, we can consciouslyprocess only a very limited amount ofinformation.”

- David Myers