Transcript multi-store-model-pph-20121

Cognitive Psychology
What is “Cognitive”
Psychology?
It’s about how our mind deals with
information, and our abilities to use
that information.
What is “Memory”?
The process of storing and
retrieving information.
Topic: MODELS OF MEMORY
1. The Multi-Store Model
(Atkinson & Shiffrin, ‘68)
Check you can…
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Describe the key features of the model
Describe encoding, capacity, and duration,
AND evidence relating to:
SM
STM
LTM
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Explain strengths & weaknesses of the model
What’s a “model”?
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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
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3 different types of memory
“CAPACITY”:
how much info
this store can
retain
– Model describes these as “memory stores”
– SM, STM, & LTM
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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
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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
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The SM takes info from one of the
sense organs and holds it in that same
form
“ECHOIC
“ICONIC
MEMORY”:
visual info from the
eyes –things you
SEE. Stored as
images.
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
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The next slide demonstrates your iconic
sensory memory at work!
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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?
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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 
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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.
C
B
G
D
V
E
P
T
NOW
How many did you get?
- answers below.
 BDTGCPEV
 Remember, to count as correct, the letters must be in
the correct sequence.
 Now try it again!!
W
Q
M
R
A
F
Z
L
NOW
How did you do this time?
- answers below
 WLFZMQRA
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.
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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)
7
3
5
1
4
9
6
8
2
NOW
How did you do?
- see below
 574831962
 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.
GCEBTECGCSEGNVQAS
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
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Not much research interest of this aspect, but…
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…some findings suggest only a few seconds before
it fades/decays (unless we rehearse it)
Activity: duration of STM
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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 303
J P
X 419
G A
K 297
Z Y
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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 progressively
worse as the delay
grew longer!
The Long Term Memory
Encoding
Activity: encoding in LTM
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Try to memorise them in order, and wait
for the word “NOW!” before you write…
NOW!
SLUMBER
SNOOZE
DREAM
SNORE
SLEEP
YAWN
DOZE
REST
NAP
KIP
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
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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!
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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!
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Iconic
Processes
Sense
Decay
Short
Store
Seven
Unlimited
Rehearsed
Semantic
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Organs
Sensory
Structure
Seconds (x2)
Lifetime
Attention
Duration
Long
Acoustic
Evaluation of the Model
Evidence
 Strengths & Weaknesses of the evidence
 Flaws
 Alternatives
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Experimental Evidence
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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)
“PRIMACY
EFFECT”:
these words
were the first
heard- they’ve
been rehearsed,
so we can recall
them from our
LTM
“RECENCY
EFFECT”:
these words are
the most
recently heard
- so we can
recall them as
they’re still in
our STM
Case Study Evidence
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Several cases of patients who
have suffered brain damage to
their hippocampus & have
memory deficits:
– H.M.
– Clive Wearing
– K.F
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Their memory loss tends to be
selective
This again supports the idea of
separate stores for different
types of memory
Brain Scanning Research
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MRI scans
show which
parts of the
brain are
being used
when certain
tasks are
carried out:
These
findings back
up the
existence of
different
stores for
different
memories
“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