Cognitive Psychology

Topic: MODELS OF MEMORY1. The Multi-Store Model (Atkinson & Shiffrin, ‘68)

What is “Memory”?The process of storing and

retrieving information.

What is “Cognitive” Psychology?

It’s about how our mind deals with information, and our abilities to use

that information.

Check you can…

Describe the key features of the model Describe encoding, capacity, and duration,

AND evidence relating to:SMSTMLTM

Explain strengths & weaknesses of the model

What’s a “model”? Not an exact copy, but a representation of something Helps us understand how something works

The Multi-Store Model of Memory

Key Features of the MSM

3 different types of memory– Model describes these as “memory stores”– SM, STM, & LTM

Any stimulus you come across has been in one or more of these stores – in this sequence!

Each store retains a different amount of info, in a different way, and for a different length of time

“DURATION”: how long this store can retain info for

“ENCODING”: the form in which

the memory is retained

“CAPACITY”: how much info this store can

retain

For us to remember a piece of info well, we need to:– Pay attention to it

• This gets it from the SM to the STM

– Rehearse it• Maintenance rehearsal keeps it in our STM• Elaborative rehearsal can get it to our LTM

Sensory Memory

Encoding

The SM takes info from one of the sense organs and holds it in that same form

“ICONIC MEMORY”:

visual info from the eyes –things you SEE. Stored as

images.

“ECHOIC MEMORY”:

auditory input from the ears –

things you HEAR. Stored

as sounds.

“HAPTIC MEMORY”:

tactile input from the body – things

you’ve TOUCHED.

Stored as feelings.

Sensory Memory

Capacity & Duration

Testing Iconic SM

The next slide demonstrates your iconic sensory memory at work!

Keep your eyes fixed on the slide and concentrate!!

7 1 V F

X L 5 3

B 4 W 7

How many letters can you recall? This was based on an experiment by

Sperling (1960): – Presented a grid of letters for less than a

second– People recalled on average 4 letters– Although, when Sperling used “partial

report” technique…– …showed that iconic memory held up to 10

items!– But decays before we can report them all

Duration:– Info decays within about 2 secs (or less)

Short Term Memory

Encoding & Capacity

Click Here to Continue

Activity 1 - Encoding in STM

You will need a pen/pencil and paper. When you go to the next page, you will be

presented with a sequence of letters, which will appear in the centre of the screen one after another.

Try to memorise the letters in sequence as they are presented.

ONLY when you see the word NOW appear, write the letters down in the same order as they were presented.

BDTCPV

NOWEG

How many did you get? - answers below.

B D T G C P E V

Remember, to count as correct, the letters must be in the correct sequence.

Now try it again!!

WLZQRANOW

FM

How did you do this time? - answers

below W L F Z M Q R A

If you did better, this fits in with previous findings… Conrad (1964) first did this experiment Visually presented students with letters one at a time Found that: letters which are acoustically similar

(rhyming) are harder to recall from STM than those which are acoustically dissimilar (non-rhyming)

This suggests that STM mainly encodes things acoustically (as sounds), even though the items were presented visually.

Activity 2: Capacity of STM As before, you will need a pen/pencil and a piece of

scrap paper. When you go to the next page, you will be presented

with a sequence of numbers, which will appear in the centre of the screen at one second intervals.

Try to memorise the numbers in sequence as they are presented, but DO NOT WRITE ANYTHING DOWN.

When you see the word “NOW” appear, write the numbers down in the same order as they were presented (serial recall)

74831962

NOW

5

How did you do? - see below

5 7 4 8 3 1 9 6 2

Miller (1956): the STM can hold ‘the magic number seven, plus or minus two’

On average, the capacity of STM is between 5 and 9 items of information.

Activity 3: Extending STM Capacity When you go to the next page, you will be presented

with a line of letters across the screen. Memorise as many of the letters as you can but do

not write anything until the word NOW appears. When you see the word NOW appear on the screen,

write down on your paper as many of the letters as you can remember, in the same order as they were presented.

G C E B T E C G C S E G N V Q A S

NOW

Could you remember more this time?

Now try it again!!

GCE BTEC GCSE GNVQ AS

NOW

You probably did better this time - Answers below.

GCE BTEC GCSE GNVQ AS

Why might this be? – (apart from having seen the stimulus material twice, an example of the practice effect). Miller (56) found that the capacity of STM could be

considerably increased by combining/organising separate ‘bits’ of information, e.g. letters or digits, into larger chunks.

Chunking involves making the info more meaningful, through organising it in line with existing knowledge from your LTM - in this case, of abbreviations for qualifications.

Short Term Memory

Duration

How long can you retain a new phone number before you have to write it down?

…if you didn’t rehearse it?

The duration for which STM can retain info is temporary – a very short time

Not much research interest of this aspect, but…

…some findings suggest only a few seconds before it fades/decays (unless we rehearse it)

Activity: duration of STM

This next experiment was first carried out by married couple Peterson & Peterson (1959)

Got students to recall combinations of 3 letters (trigrams), after longer and longer intervals.

During the intervals, students were prevented from rehearsing by a counting task!

On the next screen, you will see a trigram for a few seconds.

A 3-digit number will then appear in its place. When this happens, start counting backwards in 3’s from the number until you are told to stop.

Pens down….ready?

V J P303

X G A419

K Z Y297

Their findings suggest that our STM fades in under a half a minute if we are not rehearsing it:

After 18secs, fewer than 10%

recalled correctly.

After only 3secs, 80%

recalled correctly.

Recall got progressivelyworse as the delay

grew longer!

The Long Term Memory

Encoding

Activity: encoding in LTM

Try to memorise them in order, and wait for the word “NOW!” before you write…

SNOOZEKIPSNORERESTNAPDOZESLUMBERSLEEPYAWNDREAMNOW!

Now write down as many as you can remember.

You should have done ok, as you were using your STM

Based on Baddeley (1966) Presented lists of 10 short words one at a time Some lists were semantically similar, others not Tested immediately & then after 20 min delay Found that after 20 mins, they did poorly on the

semantically similar words This suggests that we encode LTMs according to

what they mean – so we get similar-meaning things confused!

Encoding in LTM is “semantic” – meaning-based

The Long Term Memory

Capacity & Duration

Easy!

Capacity = potentially unlimited. Duration = anything up to a lifetime. (minutes

to years) Difficult to test exact duration, but…

– Bahrick et al. (1975) tested US graduates– Shown classmate photos years later– 90% accuracy for remembering faces & names

34yrs after graduation– Declined after 48yrs, particularly for faces

Summary – Fill in the blanks!

Iconic Processes Sense Decay Short Store Seven Unlimited Rehearsed Semantic

Organs Sensory Structure Seconds (x2) Lifetime Attention Duration Long Acoustic

Evaluation of the Model

Evidence Strengths & Weaknesses of the evidence Flaws Alternatives

Experimental Evidence

Glanzer & Cunitz (1966) Read out list of words to Ps Asked them to recall as many as poss. Findings: recalled more from start and

end of list Supports the idea of there being a

separate STM & LTM, because…

The “serial position effect”:(Glanzer & Cunitz, ’66)

“RECENCY EFFECT”:

these words are the most

recently heard - so we

can recall them as

they’re still in our STM

“PRIMACY EFFECT”:

these words were the first

heard- they’ve been rehearsed, so we can recall

them from our LTM

Case Study Evidence

Several cases of patients who have suffered brain damage to their hippocampus & have memory deficits:– H.M.– Clive Wearing– K.F

Their memory loss tends to be selective

This again supports the idea of separate stores for different types of memory

Brain Scanning Research MRI scans

show which parts of the brain are being used when certain tasks are carried out:

“REMEMBER NEW

INFORMATION” – the

hippocampus is active during

this task, which requires your

LTM

“MAKE A DECISION” - the prefrontal

lobes are active now, when using your STM

These findings back up the existence of different stores for different memories