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MODELS OF MEMORY
DEFINITION OF MEMORY:
“The retention of learning or experience”
MEMORY
MEMORY ANALOGIES Library Aviary Underground map Computer STAGES OF MEMORY ENCODING STORAGE RETRIEVAL
MEMORY
THE SHORT TERM MEMORY DEFINITION: “Memory for events in the present or
immediate past” CAPACITY OF THE STM The Digit Span Test (Jacobs 1887) Magic number 7 (Miller 1956) Note: Vogel and Cowan (2001) have concluded its
more likely to be 4 items Chunking ( a useful application of psychological
theory) rehearsal
THE SHORT TERM MEMORY
ENCODING IN THE STM Predominantly acoustic (sound) Evidence = errors made with similar
sounding letters when presented visually for 0.75 seconds (Conrad 1964)
Note: research has shown we use other forms of coding also e.g. visual
DURATION OF THE STM Approx. 15 – 30 seconds without rehearsal
THE SHORT TERM MEMORY
A STUDY INTO THE DURATION OF THE STM (Peterson & Peterson 1959)
See worksheet
THE LONG TERM MEMORY
DEFINITION: “Memory for events that have happened in the past”
CAPACITY OF THE LTM Unknown Unlimited
THE LONG TERM MEMORY
ENCODING IN THE LTM Predominantly semantic Evidence: (Baddeley 1966) semantically similar
words presented to the LTM are most susceptible to being muddled up
But also acoustic, visual,
olfactory, gustatory DURATION OF THE LTM Potentially a lifetime but there
are many individual differences
THE MULTI-STORE MODEL OF MEMORY
(Atkinson & Shiffrin 1968) DIAGRAM
New idea of sensory memoryShort term and long term memories are permanent, structural components
SUPPORTING EVIDENCE (mini experiment)
1. PRIMACY/RECENCY EFFECT(Murdock1962)
The above diagram is called a serial position curve and is produced when a word list is free recalled.
PRIMACY EFFECT = RECENCY EFFECT =
2. DIFFERENT TYPES OF CODING IN STM & LTM
Baddeley (1966) studied STM P’s presented with acoustically similar words P’s then presented with semantically similar
words Results = immediate recall of acoustically
similar words was poor because the grammatical and phonemic parts of language are quickly forgotten
3. USE OF DIFFERENT AREAS OF THE BRAIN
• Using brain scans Beardsley 1997 found that people use the prefrontal cortex when doing a STM task and the hippocampus when doing a LTM task
4. STUDIES OF PEOPLE WITH MEMORY LOSS
See video and worksheet
EVALUATING THE MULTI-STORE MEMORY
POSITIVES Has evidence to support it Looks at structure AND process Enables us to make predictions
EVALUATING THE MULTI-STORE MEMORY
NEGATIVES Oversimplified Unitary stores Proposal of one short term store is wrong
(see next model) Proposal of one long term store is wrong
EVALUATING THE MULTI-STORE MEMORY Cohen & Squire (1980) distinguished between: declarative memories (memories for ‘knowing that’) and procedural memories (memories for ‘knowing how’) – people
with different conditions can lose one or the other, e.g. HM his STM was damaged but he could still learn skills (learned to play tennis)
Clive Wearing – musical ability still intact Sub-divisions of declarative = semantic
episodic (Tulving 1972) Evidence for this in brain scans using radioactive gold to
measure blood flow Model finds it difficult to explain flashbulb memories (these
can be autobiographical or historical) Examples are:
EVALUATING THE MULTI-STORE MEMORY
Rehearsal – now accepted that is not to only way into LTM
Levels of processing model (LOP) – depth of processing is more important
3 levels i) visual ii) phonetic iii) semantic Integrated STM and LTM not separate STM relies on LTM’s to chunk for instance e.g. AQABBCITVIBM Supporting evidence comes from artificial, un-
ecologically valid laboratory experiments
The Working Memory
See work sheet
Evaluating the Working Memory Model
POSITIVES Can explain partial memory difficulties e.g. case sudy of someone with normal LTM
but phonological loop difficulties Has plenty of research evidence, e.g. dual
task experiments Emphasizes the active nature of short term
memories
Evaluating the Working Memory Model
Ties in with brain mapping technology
Brain imaging studies have shown the separate areas at work, e.g. phonological store in Wernicke’s area and the articulatory rehearsal process in Broca’s area
Evaluating the Working Memory Model
NEGATIVES Little is known about the CE (vague concept) – its
probably also subdivided Using case studies of brain damaged people is
problematic Lab studies also have their drawbacks ????????
ACTIVITY
“Alice is ……
Levels of processing (LOP)
An alternative to the multistore model by Craik and Lockhart (1972) Emphasises memory process rather than
structure Based on the idea that the strength of a memory
trace is determined by how the original info was processed
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Levels of processing
Different levels of processing: Structural – appearance Phonological – auditory/sound Semantic – meaning
Structural is the shallowest, semantic is the deepest
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Levels of processing
Structural
Weak memory trace Strong memory trace
Phonological Semantic
Shallow processing Deep processing
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Levels of processing
Incoming stimuli pass through a series of analysing mechanisms
Memory traces are a product of how stimuli are analysed
Strength of trace depends on: Attention paid to stimulus Depth of processing carried out Connections with existing knowledge
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Levels of processing
The basic prediction of the LOP approach is that the amount of info P’s will recall/recognise will depend on how deeply the experimental stimuli were processed
Complete experiment into LOP
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Supporting evidence
Elias & Perfetti (1973) P’s had greater recognition of words they had
thought of similes for (semantic) than word they had thought of rhymes for (phono)
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Supporting evidence
Craik & Tulving (1975) Tested P’s in 3 ways:1. Is the word written in
capitals? BIRD (y/n)2. Does the word rhyme
with ‘love’? Dove (y/n)3. Complete the sentence
… ‘the man ate the … telephone/apple.’
Highest recognition of semantically processes stimuli, followed by phono, followed by structural
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structural
phonetic
semantic
Levels of processing - positives
Influential model that focused researchers on processes that they had tended to neglect
The idea that the nature of a memory trace depends on encoding processes is well supported by empirical evidence
Theory can be applied to everyday life, e.g. exam revision You will recall more if you use…
Depth – make sure you understand & make connections between the topics & ideas
Spread – use several different techniques on the material Elaboration – mental effort is required to store material
effectively Distinctiveness – make the material your own
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Levels of processing - negatives
Many different variables involved in determining how a stimulus is processed: Depth spread Elaboration Distinctiveness
Very difficult to isolate these variables experimentally
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Levels of processing - negatives
Semantic processing was not always best; it depended on how recall was measured and how relevant the task was (Morris et al (1977):
Recognition – semantic best Rhyming recognition – phonological best It is difficult to measure ‘depth’ P’s may not process the info the way you
want them to The theory ‘describes’ rather than ‘explains’
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Explanations of Forgetting
ACTIVITY – group work/presentations
Trace decay Displacement Lack of consolidation Interference Retrieval failure Motivated forgetting (repression)