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PYSB2
COGNITIVE PSYCHOLOGY
REMEMBERING &
FORGETTING
Models of Memory
– Multi-store Model
– Working Memory Model
– Levels of Processing
Types of Memory
– Semantic
– Procedural
– Episodic
(incl. Autobiographical)
Explanations of
Forgetting
• Trace Decay
• Displacement
• Interference
• Retrieval Failure
• Lack of
Consolidation
• Motivated Forgetting
(incl. Repression )
The study of Cognitive Processes is also called the
INFORMATION PROCESSING
approach
Remembering involves three basic processes called
THE THREE STAGES OF MEMORY
Encoding
Information is
INPUT by
selecting and
changing it into
a format that
can be stored.
Storage
Information is
STORED in
its encoded
format.
Retrieval
Information is
RECALLED in
the same format
that it is stored.
(the OUTPUT)
However there could be several different types of store.
Our own experience (Introspection) would suggest that
there are at least two very different types of memory
store.
Short Term Memory (S.T.M.)
Where information is held for a short time.
Also called Primary Memory or Working Memory.
It enables us to hold a conversation and to pay attention to our
immediate surroundings. Without it we could not function.
Long Term Memory (L.T.M.)
Where information is held for a longer time, perhaps
permanently. Also called Secondary Memory.
It enables us to remember events from the past, and all that we
have learnt. Without it we would not exist as individuals.
Next we need to establish how information is
ENCODED, STORED and RETRIEVED in each store.
The Multi-Store Model of Memory
(Atkinson & Shiffrin 1968)
ATTENTION
SENSORY
INPUT
S.T.M.
S.M.
Sensory
Memory
ENCODING
Short
Term
Memory
RETRIEVAL
ENCODING
L.T.M.
Long
Term
Memory
INFO LOSS
“forgetting”
REHEARSAL
LOOP
For an animated version visit http://aqa.psychblog.co.uk/wp-content/uploads/multistoremodel.swf
INFO
LOSS
forgetting
Sensory
Memory
ENCODING
Evidence?
DURATION
By Sensory
modality.
• S.T.M.
• L.T.M
Acoustically
Semantically
(sometimes visual)
SPERLING
BADDELEY
BADDELEY
½ - 2 secs
18 – 30 sec
Life time?
Evidence?
SPERLING
CAPACITY
Very
limited
Evidence?
SPERLING
PETERSON & PETERSON
7 + or - 2
MILLER
Infinite?
Components
of the ….
WORKING MEMORY MODEL
the ARTICULATORY PROCESS
encodes acoustically and uses
REHEARSAL to process information.
The
PHONOLOGICAL
LOOP
consists of ?
and the PHONOLOGICAL STORE
which also has a limited capacity.
(Baddeley & Hitch 1974)
The CENTRAL EXECUTIVE controls
working memory by focusing attention
on one or more of sub-systems and
determines flow into LTM.
The VISUO-SPATIAL SKETCHPAD
encodes and stores visually, limited
in capacity and duration.
You can illustrate working memory works by
asking how many windows in your house?
LEVELS OF PROCESSING THEORY
Craik and Lockhart (1972) suggested that information can be processed at different levels.
Visual by appearance
eg: starts with capital letter
Phonetic by sound,
eg: rhyme’s with ….?
Semantic by meaning,
eg: associated with?
SHALLOW PROCESSING
Needs less thinking
The deeper we process
the information the better
we remember it in LTM.
DEEP PROCESSING
More thinking involved
ELABORATION is the key to remembering information in
LTM by processing at a deeper level – analyse it, associate
it with things already in LTM, make it more meaningful.
Evaluating Models of Memory
Multi
Store
+ Has lots of empirical evidence to support it ; Miller
(1954) , Peterson & Peterson (1959), Baddeley (1966)
- Evidence lacks ecological validity (limited materials).
+ Simple to understand. - It oversimplifies memory.
Levels of
processing
+ Evidence from Craik & Tulving (1975) shows that
deeper processing gives better recall from LTM.
- What is deep? this could vary with individuals
- Does not explain role of emotion and motivation
Working
Memory
+ Evidence from Baddeley & Hitch (1974) shows that
we can process more than one task using STM.
+ Helps to explain multi-tasking & learning difficulties
- Does not explain how central executive works
Types of Long Term Memory
Procedural
Semantic
Episodic
Our “how to” memory, eg: riding a bicycle
we may not be able to explain it in words
or even know that we have this memory.
Little research has been done on this.
Our “know it” memory, eg: capital of France
because it is processed by meaning it is
organised in the way it was originally learnt.
Most memory research has looked at this.
Our “episodes of life” or autobiographical
memory, eg: last holiday, sixteenth birthday.
Includes Flashbulb Memories which are vivid,
emotive memories – ( eg 9/11 ).
The case study of CLIVE WEARING illustrates how these can function
independently and how even if only one of these are damaged the
effects can be devastating.
Explaining
Forgetting
In which of the three stages of
memory could forgetting occur?
ENCODING
STORAGE
RETRIEVAL
From introspection suggest some factors that could lead to forgetting ?
• Time
• Confusing
information
• Too much stuff to
remember
• Brain Damage
• Alcohol etc.
• Not really
wanting to recall
Each of these is explained by a different theory your
challenge is too work out which applies to which
stage, store and type of Memory.
The simple idea that memories
are lost over time is called
TRACE DECAY
RECALL %
First proposed by Hans Ebbinghaus in 1885 based on testing his own
memory for non-sense syllables (such as BEJ, ZUX) which had no
associations.
Ebbinghaus found that his memory
decayed over time, called the
“FORGETTING CURVE”.
TIME = DAYS
However he also
found that it did
not take so long
to remember
these items the
second time
around. He called
this his
“SAVINGS”
This is NOT an adequate explanation for forgetting in LTM because • Something must have remained in LTM as it could be re-learnt faster
• Older meaningful memories of important events can often be
remembered better than newer but less relevant ones.
Student
Exercise
MemEx1
Trace Decay
in STM?
Interference task
practice – count back
in three’s from 333.
Instructions:- Read the consonants that appear below
then count backwards in three’s from the number
given. Write down the letters you recall when asked.
L Z M , P V Q, X F D
763
STOP! WRITE NOW!
B F Y , G Z J, P D L
435
STOP! WRITE NOW!
K M R , H G Y, J T Z
917
STOP! WRITE NOW!
M Q L , T L Y, F R N
329
STOP! WRITE NOW!
This shows that the longer the interval before recall the more items that
are lost from memory. This is what we would expect because Peterson &
Peterson showed that the duration of S.T.M. is between 18 – 30 secs.
But Peterson & Peterson also found that as the trails when on
participants confused earlier trigrams with later ones, raising
the question was this forgetting due to ..
Trace Decay OR Interference?
Jenkins & Dallenbach(1924) showed that nonsense syllables learnt in the
evening would be remembered better than those learnt in the morning,
even though the same amount of time had past.
They concluded that the events of the day had “interfered” with the
memory for the nonsense syllables more than when people are sleeping.
LTM – INTERFERENCE provides a better explanation than trace decay.
STM – TRACE DECAY & INTERFERENCE can BOTH be used.
The memory store that TRACE DECAY applies to best is SENSORY MEMORY.
SPERLING’S (1960) experiment demonstrates this. It also makes sense in
terms of our experience of sparklers, traffic lights at night & sound echo.
Interference is forgetting due to confusion with previous or later
material. It can effect STM or LTM.
PROACTIVE
INTERFERENCE
Where information
learnt earlier
interferes with that
learnt later.
RETROACTIVE
For example you are
learning Spanish this
year, last year you
leant French.
Where information
learnt later
interferes with that
learnt first.
Qu. What is it if John calls his current girlfriend by the name of his ex?
Interference theory :-
•explains forgetting in STM & LTM when material is similar
•works better for episodic memory than semantic
•research lacks ecological validity – when do we use nonsense syllables or trigrams in everyday life?
DISPLACEMENT
Is the simple idea that new
memories will replace old ones
This theory assumes that a memory store has a limited capacity,
so which types of memory will it apply to?
NEW
INFORMATION
INPUT
S.T.M.
7+-2 items
OTHER
INFORMATION
IS LOST
Miller (1956)
found that when
STM was full up
(5 – 9 items)
new material
would push out
the old.
Also Sperling (1960) found that SENSORY MEMORY also has a very
limited capacity so this theory would also explain forgetting here butThis is NOT an adequate explanation for forgetting in LTM because • As far as we can tell LTM has an unlimited capacity.
• We can recover memories that we thought were forgotten.
Which theory best explains the Serial Position Effect?
TRACE
DECAY?
Does not explain why earliest material is remembered better
(Primacy Effect) than the material in the middle which came latter.
DISPLAC
EMENT?
Explains why material is lost from middle and why less is lost from
the end (Recency Effect) but it does not explain the primacy effect.
INTERFE
RENCE?
Offers best explanation, material in middle of curve is subject to both
Pro-active & Retro-active interference, but the material at start and
end of the list only one of these.
Primacy
Effect
Retro-active
Interference
only
Serial Position Curve
Both Pro-active & Retroactive Interference
Recency
Effect
Pro-active
Interference
only
Can you think of examples from LTM when this may not be the case?
A failure to encode information in LTM could also be caused
by some external event which wipes the memory store in
STM, here forgetting is due to the –
Lack of Consolidation
S.T.M.
Due to trauma, concussion,
alcohol, drugs, E.C.T. etc.
L.T.M.
Yarnell & Lynch (1970) showed that concussed American
footballers could recall what happened if asked immediately
(STM) but could not recall anything when asked 20 minutes
later (LTM).
Electro-convulsive therapy (ECT) seems to wipe memory of
events up to one hour before, suggesting that consolidation
takes some time.
This is a good way of explaining some forms of amnesia,
but the biological mechanisms of memory are not fully
understood so it is difficult to describe exactly how it works.
If information has been encoded and stored successfully in LTM
but still cannot be remembered then this could be due to –
Retrieval Failure
Also called Cue Dependant Forgetting
“Tip of the Tongue” is a common experience when we simply need the
right clue (or Cue) to help us recall something.
The cue usually relates to the conditions of encoding, in semantic
memory it often organisational – eg: categories.
State Dependant forgetting
Is when your internal state, mood or condition at the time of
encoding information provides a cue to remembering it.
Context Dependant forgetting
Is when the environmental factors at the time of encoding
information provides a cue to remembering it.
Godden & Baddeley (1975) showed that divers who learnt
a list of words underwater recalled it better underwater
than on land and vice versa.
WORDS
WORDS
WORKS
MOTIVATED FORGETTING – is the idea that we forget some
things (from LTM) because it is not in our best interests to
recall them; this could be due to ..
Repression
Freud (1901) suggested that this Ego Defence Mechanism
protected the conscious part of the mind (Ego) from the primitive,
socially unacceptable drives in the unconscious mind (Id).
Glucksberg & Lloyd (1967) showed that words associated with other words
that were accompanied by an mild electric shock were not recalled as well as
controls.
Levinger & Clark (1961) showed that words associated with emotionally
negative words (eg: cancer, anger) were not recalled as well as those
associated with neutral words.
Both are lab experiments and have being criticised on methodological and
ethical grounds, they are also subject to alternative explanations.
Williams (1994) interviewed 129 women 17 years after they had been sexually
abused as children, 38 % did not mention the abuse. He concluded that they
had repressed the memories. Can you provide an alternative explanation.