1 Sensory memory & Short – term memory Part I พ. ญ. กาญจนา พิทักษ์วัฒนานนท์ อายุรแพทย์เฉพาะทางระบบประสาท

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Sensory memory & Short – term memory

Part I

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สมอง

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What is memory ?• Processes involved retaining, retrieving,

using information• Original information is no longer present

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Memory

• Time machine (mental time travel)

– To go back just a moment• To the words you read at the beginning of the

sentence

– To go back many years• To events as early as a childhood birthday party

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Memory

• Time machine : Mental time travel

– Place you back in situation – Remember what we need to do later– Remember facts we have learned– Use skills we have acquired– Day-to-day activities

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Create a “Top 10 list” of : What you use memory for ?

Student top 5 items :

1. Material for exams2. Their daily schedule

3. Names

4. Phone numbers

5. Directions to places

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Top 10 list of purposeswhat you use memory for…

Answer : Differ from the ones to the others

– Student : material for exams– Construction worker : framing a house– Homemaker : cleaning the house– Business executive : ???– Politicians : ???

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Top 10 list of purposeswhat you use memory for…

• Most : Day-to-day activities

– Labeling familiar objects : “ Book ” is ??– Having conversations : talking , Q & A– Knowing what to do in restaurant : paying check

– Finding the way to somewhere : map

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How important of memory..

• When people lose their memory..

• What happens to people’s lives..

For example : Clive Wearing

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Clive Wearing

• Musician & choral director in England• Viral encephalitis : destroyed temporal lobe

• Cannot forming new memories ( LTM )– Remember what just happen– Then forget everything else

• Problem : he react like 1st meet when he meet someone in a few minutes again

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Clive Wearing’s diary

• He has no memory of ever writing anything except for the sentence he has just written

• He is confused– He record events in his handwriting– He has no memory for writing events– He denies that events are his

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Important of memory• Wearing lives totally within a few minutes

• He describes his life as being “like death”

• He has no ability to have normal life

• He cannot participate in life in any meaningful way

• He need to be constantly cared for by others

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Chapter summery 1• Memory is the process involved in retaining,

retrieving, and using information about stimuli, images, events, ideas, and skills after the original information is no longer present.

• It is important for dealing with day-to-day events, and cases such as Clive Wearing’s illustrate the importance of memory for normal functioning.

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basic principles of memory :

The modal model of memory

– Richard Atkinson & Richard Shiffrin’ s : 1968

– Proposed 40 years ago

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Stages of modal model

• Called structural features of the model

• There are 3 major structural features– Sensory memory– Short-term memory– Long-term memory

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Structural features

1 sensory memory– Initial stage – Holds all incoming information for seconds or

fractions of a second

2 short-term memory : STM– Holds 5-7 items for about 15-20 seconds.

3 long-term memory : LTM– Hold a large amount of information for years

or even decades.

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Control processes

• Active processes that can be controlled by the person and may differ from one task to another.

• For example :

Rehearsal , Attention , Relating

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Rehearsal

• Repeating a stimulus over and over

• You might repeat a telephone number in order to hold it in your mind after looking it up in the phone book.

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Attention

• You selectively focus on other information you want to remember

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Relating

• Relating the numbers in a phone number to a familiar date in history

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Phone number for Mineo’s Pizza

• Rachel looks up the number in a phone book– All of the information that enters her eyes is

registered in sensory memory.

• Rachel focuses on the number for Mineo’s pizza using the control process of selective attention, so the number enters STM– Rachel uses the control process of rehearsal to

keep it there

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• After Rachel has dialed the phone number– She may forget it because it has not been

transferred into long-term memory.

• She decides to memorize the number so next time she won’t have to look it up in the phone book.– Transfers the number into LTM


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• A few days later,

• When Rachel’s urge for pizza returns, she remembers the number.

• The information must be retrieved from LTM so it can reenter STM to be used.


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Chapter summery 2

• Atkinson and Shiffrin’s modal model of memory consists of three structural features – sensory memory, short-term memory, and long-term memory.

• Another feature of the model is control process such as rehearsal and attentional strategies.

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Sensory memory

• Sensory memory is the retention, – for brief periods of time, – of the effects of sensory stimulation.

• Example : Brief retention for the effects of visual stimulation– The trail left by a moving sparkler– The experience of seeing a film

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The sparkler’s trial

• A sparkler can cause a trail of light when it moved rapidly.

• The lighted trail is a creation of your mind, which retains a perception of the sparkler’s light for a fraction of a second.

• This retention of the perception of light in your

mind is called the persistence of vision.

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Projector’s shutter

A person viewing the film

• sees the progression of still images as movement

• doesn’t see the dark intervals between the images because the persistence of vision fills in the darkness by retaining the image of previous frame.

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Flickers of film

• The period between the images is too long (more than 24 times/sec.)

• Longer dark interval

• The mind can’t fill in the darkness completely

• A person perceive a flickering effect

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• Icon = image

• An array of letters (12 icon in matrix)

• Flashed on the screen for 50 ms.– 50 ms = 50/1000 sec.

• Asked participants to report a whole

Sperling’s experiment :Measuring the visual icon

XMLTAFNBCDZP

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The whole report method

• They were able to report an average of 4.5 out of the 12 letters– Concluded ??? : the exposure was brief,

participants saw only an average of 4.5 of the 12 letters

– Perhaps ??? : participants saw most of the letters immediately, but their perception faded rapidly


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Determine which of 2 possibilities is correct

• Partial report method– Flashed the matrix for 50 ms– Immediately after it was flashed (turned off)– Sounded one of the following cues tones

• High pitched : top row• Medium-pitched : middle row• Low-pitched : bottom row

– To indicate which row of letters the participants were to report


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Partial report method

• Sound after flashed off– Actual letters were no longer present– Participant’s attention was directed not to the

actual letters– Participant’s attention was directed to

whatever trace remained in their mind– Cues tones directed participants to focus their

attention onto one of the rows


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Partial report method

• Result : they correctly reported an average of about 3.3 of the 4 letters (82 %)

• Conclude : they saw 82% of letters

They were not able to report all of these letters because they rapidly faded as the initial letters were being reported


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To determine the time course of this fading

• Delayed partial report method– The presentation of cue tones was delayed

for a fraction of a second after the letters were extinguished

– Result : delayed for ½ second report only slightly more than 1 letter in a row

– Result : same number of whole report method


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Sperling’s experiment

• Immediately after flashed off

– All or most (82%) of stimulus is available for perception

– This is sensory memory

– Sensory memory registers all or most of the information that hits our visual receptors

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• Over the next second after flashed off

– Sensory memory fades

– Information decays within less than second

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• A short-lived sensory memory registers all or most of the information that hits our visual receptors – Capacity of sensory memory = large

• but that this information decays within less than a second.– Duration of sensory memory = brief

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Duration of sensory memory

• Sensory memory for visual stimuli– Iconic memory = visual icon– Persistence of vision– Duration less than one second

• Sensory memory for auditory stimuli– Echoic memory– Persistence of sound– Duration lasts for a few second

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Important of sensory memory

• Collecting information to be processed

• Holding the information briefly while initial processing is going on

• Filling in the blanks when stimulation is intermittent

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Chapter summery 3

• Sperling used two methods, whole report and partial report, to determine the capacity and time course of visual sensory memory.

• The duration of visual sensory memory (iconic memory) is less than 1 second,

• The duration of auditory sensory memory (echoic memory) is about 2-4 seconds.

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Short-term memory

• Brief duration– What is the duration of STM ?

• Most of information is lost– How much information can STM hold ?

• Some of information store to be long-term memory

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Short-term memory

• Whatever you are thinking about right now, or remember from what you just read, is in your STM

• How do we understand this sentence ?

“The human brain is involved in everything we know about the important things in life, like music and dancing”

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What is duration of STM ?

• John Brown , Lloyd Peterson , Margaret Peterson : experiments to determine the duration of STM

• Remembering three letters– Tell the person that you are going to read three letters followed

by a number– Once the person hears the number he should start counting

backward by 3’s from that number– When say Recall : write down the three letters heard at the

beginning– Once the person start counting, – time 20 seconds and say “Recall”

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Remembering 3 letters

• Peterson and Peterson’s results

3-second delay : 80 % remember of letters

18-second delay : 10 % remember of letters

• Participants forgot the letters because their memory trace decayed during the 18 seconds

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• Peterson’s results performance average over many trials

• G. Keppel and Benton Underwood (1962)

– Re-analysis Peterson’s results

– Re-analysis compared 1st & 3rd trial performance

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• G. Keppel and Benton Underwood– First trial : a little falloff– Third trial : seeing a drop-off

• Why would memory become worse after a few trial ?– The drop-off in memory was due to proactive

interference (PI) = interference that occurs when information that was learned previously interferes with learning new information


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Proactive interference

• What might happen when Rachel calls the number she had memorized for Mineo’s Pizza (521-5100) changed to 522-4100

Rachel tries to remember the new number

• She make mistakes at first

• PI is causing her memory for the old number to interfere with her memory for the new number

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Proactive interference

• Old number : 521-5100• New number : 522-4100

• New number is similar to the old one

– Old number adds to the interference

– Old number makes it harder to remember the new number

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Proactive interference (PI)

• PI is a basic mechanism of forgetting

• PI is about 15 – 20 sec.

• PI Rehearsal is prevented outcome of PI

= effective duration of STM decreased

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Chapter summery 4

• Short-term memory is our window on the present.– Brown, and Peterson, determined that the

duration of STM is about 15-20 seconds.

• They interpreted the short duration of STM as being caused by decay, but a later reanalysis of their data indicated it was due to proactive interference.

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What is the capacity of STM ?

• The information is not only lost rapidly from STM, but there is a limit to how much information can be held there.

• This capacity can be measured by Digit span ( the number of digits a person can remember ).

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Coglab : Digit span

• Using an index card or piece of paper, cover all of the numbers below

2 1 4 9 3 9 6 7 8 6 4 9 7 8 4 7 3 8 2 0 1 5 8 4 2 6 1 4 3 2 4 8 2 3 9 2 8 0 7 5 8 5 2 9 8 1 6 3 7

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• Move the card down to uncover the first string of numbers.

Coglab : Digit span

2 1 4 9 3 9 6 7 8 6 4 9 7 8 4 7 3 8 2 0 1 5 8 4 2 6 1 4 3 2 4 8 2 3 9 2 8 0 7 5 8 5 2 9 8 1 6 3 7

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• Read the numbers , cover them up, and then write them down in the correct order.

Coglab : Digit span

2 1 4 9 3 9 6 7 8 6 4 9 7 8 4 7 3 8 2 0 1 5 8 4 2 6 1 4 3 2 4 8 2 3 9 2 8 0 7 5 8 5 2 9 8 1 6 3 7

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• Then move the card to the next string and repeat this procedure until you begin making errors.

Coglab : Digit span

2 1 4 9 3 9 6 7 8 6 4 9 7 8 4 7 3 8 2 0 1 5 8 4 2 6 1 4 3 2 4 8 2 3 9 2 8 0 7 5 8 5 2 9 8 1 6 3 7

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• The longest string you are able to reproduce without error is your digit span.

• The typical span is

between 5 and 8

Coglab : Digit span

2 1 4 9 3 9 6 7 8 6 4 9 7 8 4 7 3 8 2 0 1 5 8 4 2 6 1 4 3 2 4 8 2 3 9 2 8 0 7 5 8 5 2 9 8 1 6 3 7

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What is the capacity of STM ?

This capacity can be measured by Digit span ( the number of digits a person can remember )

• The typical span is between 5 and 8 digits

• According to measurements of digit span, the capacity of STM is 5 – 8 items.

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The magic number sevenplus or minus two

• George Miller (1956) : chunking concept

• The famous paper titled : “ The magic number seven, plus or minus two ”

• Explain : How we remember words and combinations of words ?

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How we remember words and combinations of words

• Trying to remember the following words

– Monkey– Child– Wildly– Zoo– Jumped– City– Ringtail– Young

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• How to remember :– How many units are there in this list ?

• 8 words : 4 pairs» Ringtail monkey» Jumped wildly» Young child» City zoo

– We can take this one step further by arranging these groups of words into one sentence.

» The ringtail monkey jumped wildly for the young child at the city zoo.


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• Is the sentence about the child watching a monkey at the zoo 8 items, 4 items or 1 item ?

• Small units (like words) can be combined into larger meaningful units (like phrases), or even larger units (like sentences, paragraphs, stories)


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• Chunk : a collection of elements that are strongly associated with one another but are weakly associated with elements in other chunks– Ringtail

• Associated with : monkey• Not ass. with : child , jumped

Concept of chunking

The ringtail monkey jumped wildly for the young child at the city zoo

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• We can recall a sequence of 5 – 8 words

• Chunking increase the memory span to 20 words or more

• Meaning can increase our ability to hold information in STM

Concept of chunking

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• S.F. participant : typical 7 digits span

• After extensive training : 79 digits span

• How did he do it ?– 3492 : 3 min and 49.2 sec , near world record mile time– 893 : 89.3 , very old man

• S.F. was a runner used memory stored in LTM about runner times

• S.F. used a chunk to remember best

K. Anders Ericcson and coworkers (1980)

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• William Chase & Herbert Simon

– They showed chess players pictures of chess pieces on a chessboard for 5 sec

– Then asked to produce the positions they had seen

– Results compared : chess master & beginner

Concept of chunking

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Actual game positions

• Chess master : correct 16 / 24 ( 1st try )

• Beginner : correct 4 / 24 ( 1st try )

Concept of chunking

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Actual game positions

• Chess master : correct 24 / 24 ( 4th try )

• Beginner : still incorrect ( 7th try )

Concept of chunking

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Random positions

• Chess master : 3 / 24

• Beginner : 3 / 24

Concept of chunking

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Actual game positions : master superiorly

His ability to group the chess pieces into meaningful chunks

Used interaction between STM & LTM

Random positions : master vanished

Concept of chunking

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• Chunking is an essential feature of STM because it expands the capacity of STM so it can handle 5-8 chunks rather than just 5-8 items

• This enables the limited-capacity STM to deal with the large amount of information involved in many of tasks we perform everyday ( chunking letters into words as you read )

Concept of chunking

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Chapter summery 5

• The capacity of STM is 5-8 items, as measured by digit span. – This capacity can be expanded by chunking,

so that it is possible to remember 5-8 chunks rather than 5-8 digits.

• Examples of chunking are the memory performance of the runner S.F. and how chess masters use their knowledge of chess to remember chess piece positions.

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How is information coded in STM ?

• Coding : the way information is represented

• Physiological approach to coding : How a stimuli is represented by the firing of a number of neurons

• Mental approach to coding : How a stimuli or an experience is represented in the mind

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Physiological approach to coding : Distributed code

• 1>2>3• 1<<2>3• 1<2<3• 1<2>>3• 1>>2<<3

• Bill• Samantha• Roger• Grace• Ellen

Groups of neurons firing : different pattern

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Mental approach to coding

After you have just finished listening lecture

• Some of ways you might remember what happened in class– Remembering the sound of your professor’s

voice– Imagining what your professor looks like– Remembering what your professor was talking

about

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Auditory coding

• R. Conrad 1964• Participants saw a number of target letters flashed

briefly on a screen• Participants were told to write down the letters in

the order they were presented

• Finding : when participants made errors, they were most likely to misidentify the target letter as another letter that sound like the target ( F S , X )

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• Conrad concluded :

Code for STM is auditory

( based on the sound of stimulus ),

rather than visual ( based on the visual appearance of the stimulus )

Auditory coding

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Visual coding : examples

• Remembering the details of a diagram or an architectural floor plan, require visual codes

• Radicals & Characters in Chinese language

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Visual coding

• Guojun Zhang and Herbert Simon 1985• Presented Chinese language symbols to native-

speaking Chinese participants

• Stimuli : Radicals , Characters– Radicals : symbols that are part of Chinese

language & that are not associated with any sound

– Characters : consist of a radical plus another symbol & do have sound

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• Participants were asked to reproduced a series of Characters

• They were able to reproduce a string of 2.7 radicals : recall based on visual coding

• They were able to reproduced a string of 6.4 characters : greater recall when auditory coding

Visual coding

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• Both involved in STM

• Superior memory for Characters from :

• Characters has sound / auditory coding

• Radicals no sound , no meaning / visual coding

Visual coding / Auditory coding

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Semantic coding

• Delos Wickens and coworkers 1976

• 3 different groups of participants :• A professions group• A meat group• A fruit group

• Each group listened to 3 words, counted backward for 15 sec, then attempted to recall 3 words

• Repeated 4 trial, different words in each trial

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• Trial 2 & 3 : decrease in due to build up PI ( Proactive Interference )

• Trial 4 same category : remain low for fruit group

• Trial 4 switch category : release from PI in Profession & Meat groups improved

Wickens’ experiment : result

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• The release from PI depends on the words’ categories ( fruit, meat, profession )

• Different categories : different meaning

• This results demonstrate the operation of semantic coding in STM

Wickens’ experiment : concluded

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Chapter summery 6

• Information can be coded in STM in terms of sound (auditory coding), vision (visual coding), and meaning (semantic coding).– Auditory coding was illustrated by Conrad’s

experiment that analyzed the type of errors made in memory for letters.

– Visual coding was illustrated by Zhang and Simon’s experiment with Chinese characters,

– semantic coding by Wickens’ release from proactive interference experiment

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Working memory

พญ. กาญจนา พ�ทักษ์�วัฒนานนทั�

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Working memory

• Alan Baddeley and Graham Hitch 1974

• The modern model of memory• STM be replaced by working memory

• Working memory : a mechanism that consists of a number of specialized components

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• Reading text & Remember numbers• Keep these numbers in your mind ( 7 1 4 9 ) as

you read the following passage :

» Baddeley reasoned that if STM had a limited storage capacity of about the length of a telephone number, filling up the storage capacity should make it difficult to do other tasks that depend on STM. But he found that participants could hold a short string of numbers in their memory while carrying out another task, such as reading or even solving a simple word problem. How are you doing with this task? What are the numbers ? What is the gist of what you just read?

Working memory

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• Reading text & Remember numbers

– How are you doing with this task ?

– What are the numbers ?

– What is the gist of what you just read ?

Working memory

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• Reading text & Remember numbers• Baddeley’ s participants were able to read

while simultaneously remembering numbers

• Digit span task : handled by one component• Comprehending the paragraph : handled by the

others

• Concluded : the short term process must consist of a number of components that can function separately

Working memory

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• Baddeley decided the name of the short term process should be changed from STM to working memory

• Working memory : a limited-capacity system for temporary storage and manipulation of information for complex tasks such as comprehension, learning, reasoning

Working memory

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• Working memory differs from STM

• STM is a single component, – whereas working memory consists of a number of parts

• STM is with holding information for a brief period of time,

– whereas working memory is concerned with the manipulation of information that occurs during complex cognition

» Problem solving» Thinking» Attention» language

Working memory

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Chapter summery 7

• The short-term memory component of the modal model was revised by Baddeley in order to deal with results that couldn’t be explained by a single short-term process.

• In this new model, working memory replaces STM

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Atkinson and Shiffrin’s model of memory

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• Manipulation of information through the action of 3 components :

• Phonological loop : verbal & auditory information

• Visuospatial sketch pad : visual & spatial information

• Central executive

Working memory

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Phonological loop

• Holds verbal and auditory information

• Example :

• When you try to remember a telephone number or a person’s name

• Try to understand what your professor is talking about

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Visuospatial sketch patch

• Holds visual & spatial information

• Example :

• When you form a picture in your mind

• To do a tasks like solving a puzzle

• Finding your way around campus

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Central executive

• Central executive pulls information from LTM

• Central executive coordinates the activity of the phonological loop and visuospatial sketch patch by – focusing on specific parts of a task – switching attention from one part to another

• Central executive is where the major work of working memory occurs

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To decide how to divide attention between different tasks

Imaging you are driving in a strange city

The news is broadcast on the car radio

A friend in the passenger seat is reading you directions to a restaurant

– phonological loop : verbal direction– sketch pad : visualized a map of streets

• Central executive : coordinating & combining both• Central executive : ignore the car radio

Central executive

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Chapter summery 8

• Working memory is a limited-capacity system for storage and manipulation of information in complex tasks.

• It consists of three components– the phonological loop, which holds auditory or verbal

information, – the visuospatial sketch pad, which holds visual and

spatial information, – the central executive, which coordinates the action of

the phonological loop and visuospatial sketch pad.

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Phonological loop

• Phenomena support the idea of a system specialized for language

• The phonological similarity

• The word - length effect

• Articulatory suppression

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Phonological similarity effect

• Conrad’s experiment : showed that people often confuse similar-sounding letters

• T , P• F , X , S• Result : Auditory coding in STM

• Words are processed in the phonological loop of working memory

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• Task 1 : Slowly read the following letters. Look away and count to 15. Then write them down.

g c b t v p

• Task 2 : Now do the same thing for these letters.

f l k s y g


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• Which of the two tasks was more difficult?• Task 1 : more difficult• Task 1 : similar-sounding letters

• People confuse the similar – sounding letters and report letters that weren’t present ( d e z )


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• occurs when letters or words that sound similar are confused


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• Task 1 : Read the following words, look away, and then write down the words you remember.beast, bronze, wife, golf, inn, limb, dirt, star

• Task 2 : Now do the same thing for the following list.alcohol, property, amplifier, officer, gallery, mosquito,

orchestra, bricklayer

Word-Length effect

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• Which of the 2 tasks was more difficult ?• Task 2 : more difficult• Task 2 : the words more longer

• Longer words takes longer …..– to rehearse the long words – to produce them during recall

Word-Length effect

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Word-Length effect

• occurs when memory ( for lists of words ) is better for short words than for long words

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• English numbers : one two three four five six …

• Welsh numbers : un dau tri pedwar pump chwech …

• English more shorter & easier than Welsh• American children have a larger digit span

than Welsh children

Word-Length effect

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• People are able to remember the number of items that they can pronounce in about 1.5 – 2.0 sec

• Try to counting out loud, as fast as you can, for 2 sec

• The number of words you can say should be close to your digit span

Word-Length effect

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• Task 1 : Read following list. Then turn away and recall as many words as you can.

• Dishwasher, hummingbird, engineering, hospital, homelessness, reasoning

• Task 2 : Read the following list while repeating the word “the” out loud. Then turn away and recall as many words as you can.

• Automobile, apartment, basketball, mathematics, syllogism, Catholicism

Articulatory suppression

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• Which of the 2 tasks was more difficult ?

• Task 2 : harder

• Task 2 : repeating the, the, the,… overloads the phonological loop.

• The, the, the,….reduces the ability to remember lists of words


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occurs when a person is prevented from rehearsing items to be remembered by repeating an irrelevant sound

such as “ the ”

( the, the, the, … )

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• Eliminates the word-length effect

: short word leave more space for rehearsal

The, the, the,… eliminates this rehearsal advantage for short words


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• Reduces the phonological similarity effect

: reading initially represented in the visuospatial sketch pad,

and then transferred to the phonological loop

The phonological loop is engaged by the, the, the,…


135

136


• Articulatory suppression has 3 effects :

1. it reduces the memory span : speaking interferes with rehearsal

2. it eliminates the word-length effect

3. it reduces the phonological similarity effect for reading words

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Chapter summery 9

• The following effects can be explained in terms of operation of the phonological loop: – (a) phonological similarity effect – (b) word-length effect – (c) articulatory suppression

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Visuospatial sketch pad

• Lee Brooks experiments 1968

Holding a verbal stimulus in the mind– Task 1 : memorize the sentence below, and

then without looking at it, consider each word in order and say “yes” if it is a noun and “no” if it isn’t a noun

John ran to the store to buy some oranges

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Holding a verbal stimulus in the mind– Task 2 : memorize the sentence below, and

then use fig. 5.18 to indicate whether each word in the order it appears in the sentence, point to the “Y” if the word is a noun and to the “N” if it isn’t ( move down a row in the display in fig. 5.18 for each new word )

The bird flew out the window to the tree


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Holding a verbal stimulus in the mind

• Which of the 2 tasks was more difficult ?– Task 1 : said Yes or No more difficult

• Task 1 : stimulus & task verbal overload phonological loop

– Task 2 : stimulus verbal , task spatial • Task 2 : the processing was distributed between

the loop and sketch pad task 2 : easier


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Holding a verbal stimulus in the mind

Holding the sentence : verbal taskSaying “yes” or “no” : verbal taskPointing to “Y” or “N” : spatial task

Task 1 : overloading phonological loopTask 2 : distributing processing across both


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Holding a spatial stimulus in the mind Task 3 : visualize the F in fig. 5.20.

then look away from the figure,

and while visualizing the F in your mind,

start at the upper left corner ( the one marked with the * )


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Holding a spatial stimulus in the mind Task 3 :

visualizing the F in your mind,

start at the upper left corner ( the one marked with the * )

moving around the outline of the F in a clockwise direction in your mind,

point to Y in fig. 5.18 for an outside corner, and N for an inside corner


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Holding a spatial stimulus in the mind


Y YY N

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task 4 : visualize the F again,

but this time, as you move around the outline of the F in a clockwise direction in your mind,

say “yes” if the corner is an outside corner ( like the first one )

or “no” if it is an inside corner


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Which was easier, pointing to “Y” or “N” or saying “yes” or “no” ?

saying “yes” or “no” is easier


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Holding the F in the mind : spatial taskSaying “yes” or “no” : verbal taskPointing to “Y” or “N” : spatial task

Task 3 : overloading to spatial taskTask 4 : distributing processing across both


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Chapter summery 10

• Brooks did some experiments that indicated that two tasks can be handled simultaneously if one involves the visuospatial sketch pad and the other involves the phonological loop.

• Performance decreases if one component of working memory is called on to deal with two tasks simultaneously.

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Central executive

Does most of the work of working memory

• Coordinates the operation of the phonological loop & visuospatial sketch pad

• Paying attention to relevant information

• Controlling the suppression of irrelevant information

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Central executive

Coordinate :

phonological loop + visuospatial sketch pad

– Listening to the friend guiding the way

– Looking for street when driving a car

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Central executive

Suppresses irrelevant information + pays attention relevant information

– Ignore : radio sound

– Select : friend voice

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Central Executive

Adam Gazzaley and coworkers 2005

“ face relevant ” task

• Participants were told to remember the faces and ignore the scenes when the four cue stimuli ( 2 faces & 2 scenes ) were presented

• After 9 second delay• Indicate whether the face presented during the

test period matched one of the cue faces

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Central Executive


“passive” task

• Participants just looked at the pictures

• and pressed a button indicating the direction of the arrow during the test

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Central Executive


• Measured the fMRI response of an area in the temporal cortex that responed to scenes

• Measured how accurately participants were able to indicate whether the test face matched the cue faces

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Central Executive


Results : 2 groups of participants

• “good suppressors” : less brain activity

• “poor suppressors” : greater brain activity when they were supposed to be ignoring the scenes than during the passive condition

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Central Executive


• Good suppressors : 89 % correctly• Poor suppressors : 67 % correctly

• Concluded : the ability to suppress irrelevant information, which is a central executive function, results in better memory for relevant information

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Chapter summery 11

• Researchers are just beginning to understand the functioning of the central executive.– One function, the suppression of irrelevant

information, was studied by Gazzaley by measuring brain activity and memory performance during a memory task that involved suppression.

• The results of this experiment showed that greater suppression, measured by brain activity, was associated with better performance in the memory task.

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Update on model

STM (Atkinson, Shiffrin) working memory (Baddeley)

• Can’t explain some results

– The,the,the,…. decrease in memory span ( but only slightly 7 5 )

– Should decrease more than this results

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Baddeley’s revised working memory model

• Added : episodic buffer

• Models designed to explain mental

functioning are constantly being refined and modified to explain new results

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Episodic buffer

• Episodic buffer is basically a “backup” store that communicates with both LTM and the components of working memory

– It can hold information longer

– It has greater capacity

than phonological loop or spatial sketch pad

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Chapter summery 12

• The working memory model has been updated to include an additional

component called the episodic buffer, which has a greater capacity and can hold information longer than the phonological loop or visuospatial sketch pad.

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Working memory & Brain

• Prefrontal cortex ( PF ) : Working memory

– Receives input from the sensory areas ( processing incoming visual & auditory information )

– Receives signals from areas involved in carrying out actions

– Is connected to areas in the temporal cortex that are important for forming LTM

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Prefrontal cortex : working M.

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Delayed-response task

Experiment in monkey

• Task :– Monkey hold information in working

memory

• Delay period :– Retrieve information in working memory

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Delayed-response task• Task :

– Monkey sees a food reward in one of two food wells– Both wells are then covered– A screen is lowered

Delay– Screen is raised again– Monkey reach a food wells

• Correct obtain a reward• Incorrect no reward

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delayed-response task in trained-monkeys


Observe Delay Correct : reward

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in prefrontal cortex damaged-monkeys


Removed prefrontal cortex correct by change

177

Chapter summery 13

• Behaviors that depend on working memory can be disrupted by damage to the prefrontal cortex.

• This has been demonstrated by testing monkeys on the delayed response task.

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• Prefrontal cortex : damage / removed

– Infants younger than 8 months : not develop

– Out of sight , Out of mind


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Neuron that hold information

• Shintaro Funahashi and coworkers 1989

Recorded from neurons in a monkey’s PF

• Delayed-response task

x x

--ll---------------- -------llllllllllllllllll- ---------------ll--

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Shintaro Funahashi & coworkers 1989

• Recorded from neurons in a monkey’s prefrontal cortex– While it carried out a delayed-response task

• To confirm :

prefrontal cortex / working memory– Memory

• Hold information after the original stimulus is no longer present

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x x


• Monkey first looked at a fixation point : X

• Square was flashed then off

• After delay : off fixation X

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• Shintaro Funahashi and coworkers 1989

Monkey move eyes

to where the square has been flashed

Monkey remembered the location of the square

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x x


• Funahashi found neurons that responded when the square was flashed in a particular location and that the neurons continued responding delay

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x x


• The firing of these neurons indicates that an object was presented at a particular place, and this information remains available for as long as these neurons continue firing

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Neurons from many brain areas that response during delay in a working memory

– Primary visual cortex : receives visual signals

– Inferotemporal cortex : a visual area responsible for perceiving complex forms

– PF prefrontal cortex : working memory

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Chapter summery 14

• There are neurons in the prefrontal cortex that fire to presentation of a stimulus and continue firing as this stimulus is held in memory.

188

Brain imaging in humans

• PET ,fMRI

Showed many area are involved in working memory : prefrontal, frontal, parietal, cerebellum

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Chapter summery 15

• Brain imaging experiments in humans reveal that a large number of brain areas are involved in working memory.

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American sign language

• Visual language

visuospatial sketch pad

• Contain specific gestures (hand & arm)

• Used by deaf people

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Margaret Wilson andKaren Emmorey 1977

• Showed that

– ASL have phonological similarity effect

– ASL have word-length effects

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Memory for lists of words that are signed similarly is worse than memory for words that are signed differently

Memory is worse for wordsthat have signs thattake longer to produce

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Concluded of Wilson & Emmorey

• ASL have phenomenon of phonological loop (phonological similarity + word-length effect)

• Phonological loop appears to process language input regardless of whether the language is created by sound or by gestures

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Finger spelling for measures memory span

Compared digit span of spoken language

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Results of memory span from 2 studys

Blue : letter spanGray : digit span

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Memory span

• Spoken language : digit span

• ASL : letter span (finger spelling)

Different results from different experiment– Different procedure, stimuli, participants

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Wilson & Emmorey results

• No difference in letter span for speaking & signing

• Duration & others factors are equated

• Suggest : working memory capacity for speaking & signing is the same

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Bavelier & coworkers results

• There is a difference in letter span for speaking and signing

• Suggest : working memory capacity for speaking and signing may differ in capacity– Perhaps due to differences between the

memory mechanisms for auditory and visual stimuli

200

Chapter summery 16

• Comparisons of working memory for signers who use ASL and speakers of English show that the phonological similarity effect and word-length effect occur for both.

• There is controversy regarding whether digit span is different for speakers and signers, but tests of more complex language abilities indicate no difference between signers and speakers.

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1 Sensory memory & Short – term memory Part I พ. ญ. กาญจนา พิทักษ์วัฒนานนท์ อายุรแพทย์เฉพาะทางระบบประสาท