Transcript 15 Memory-handout - University of Illinois Archives

MEMORY UNIT
Amnesias: some people are unable to explicitly remember any
new information they learn. When introduced to someone they
met a few minutes ago, they cannot remember ever having met
this person. However, they can still learn to do some types of
new tasks.
Different ways of thinking about new information has a large
effect on what we remember. Why? What might help us to
remember better? What causes us to forget?
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Three important points about memory
(of many that could be chosen)
(1) Memory is not the same as recollection.
Memory is critical for much that we do.
There are different types of memories that may be affected
by different manipulations, traumas, etc.
(2) Active, elaborative processing of information is important for
ensuring good retention of the information.
(3) The context match between when we learn something and
when we remember it has a large influence on how well we
remember.
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MEMORY UNIT
A brief glimpse …………………..
Structure - a traditional view (for 50 minutes)
* Short Term Sensory Store (STSS)
** Iconic & Echoic
* Short-term Memory (STM) or Working Memory (WM)
* Long Term Memory (LTM)
** Declarative & Procedural
** Amnesias
Process
* Encoding
* Storage - capacity & forgetting
* Retrieval - strategies & codes
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Working Memory (short-term memory)
Storage (Capacity & Duration)
* Capacity - memory span is 7 + 2 items (with recall
immediately after presentation)
But …. What’s an item?
Chunk - a meaningful unit of information
e.g. 2 1 7 2 4 4 1 0 9 5 or (217) 244-1095
* Duration - See letters then (to prevent rehearsal) count
backwards from 299 by 7s
** 50% recall in 15 second
Encoding
* Conrad effect - present letters to be memorized on a screen
** Recall errors are acoustic rather than visual
(Present E - erroneously recall D not F)
(but can be visual or semantic at times)
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Long Term Memory (LTM)
Storage (Capacity & Duration)
* Capacity & Duration - for practical purposes, unlimited
Then why is forgetting observed?
•
Interference rather than decay (primarily)
• Memories are “there”
• Retrieval difficulties
•
Evidence against decay - less forgetting when asleep
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Forms of Interference:
Retroactive Interference -- effect of learning later material
Group
Experimental
Control
Original
Learning
List A
List A
Interpolated
Learning
Test
List B
Rest
List A
List A
Proactive Interference -- effect of having learned earlier material
Group
Experimental
Control
Prior
Learning
Learning
List B
None
List A
List A
Test
List A
List A
To reduce interference: Use material from different semantic
categories for different lists
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Encoding
How do you get information into LTM?
(a) Maintenance (rote) rehearsal - emphasize phonological
aspects of material
* Good for WM poor for LTM
(b) Elaborative rehearsal - emphasize semantic association
* Good transfer to LTM -- example
In what form is information encoded into LTM?
* Primarily Semantic (though can store other forms)
** Thirty seconds after hearing or reading two brief narratives
they can not distinguish them if they had the same meaning
* Mnemonic strategies: Method of Loci, Rhyming … --good
for remembering arbitrary information
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Elaborative processing is critical
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The time spent memorizing and the
intention to remember influence
retention only if you actively process
and elaborate the material
Construct an integrated representation
of the new material (so it makes sense)
and connect it to what you already know
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Retrieval from LTM - importance of context
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Very common occurrence
Environmental context
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State-dependence - internal context
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Learn underwater or on land.
Test underwater or on land.
Performance 50% better when match
Better memory when match of states
(even find some with mood)
Why? Indication of relevance
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Prior knowledge importance in retrieving from
LTM
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Try to remember your last physical exam
See that some of what you remember is
based on your knowledge of physicals and
some on the actual events from that physical
Also depends on match of prior knowledge
you used in encoding and retrieving -- often
have schemas (or organized knowledge) for
encoding and retrieving routine events, etc.
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Some practices for good learning
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Chunk information -- active processing into
chunks allows for easier recall later
Be an active learner -- elaborate, summarize,
relate information to what you already know,
organize the information
Vary study and try to make it like the time
when you may need to retrieve information -space study, vary context, reinstate learning
(mentally), practice retrieving information
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Differentiating WM from LTM
(& among varieties of LTM)
Serial position (recall) curves
* Best recall at beginning (LTM) & end (WM) of list
Recency effect - diminished when another task is
performed after the word list has been
presented. Primacy effect is unaffected.
Primacy effect - diminished with fast presentation, low
frequency words, unrelated words.
Recency effect is unaffected.
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Primacy
Recency
Without delay
Probability
of
report
With delay
1
2
3 4 5 6
Serial position
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With delay between study and test, recency part of curve
decreases much more than primacy or middle.
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Clinical/Neuroanatomical Evidence
Bilateral lesions of the hippocampus
** Pre-surgical WM and LTM are ok
** Post-surgical
WM is ok
Failure to develop (some) new LTMs
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Types of Memory and Amnesia
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Declarative memory - “knowing that…”
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Examples
 “I am in medical school”
 My sister called last night.
Can be learned relatively quickly
Flexible
Procedural memory -”knowing how”
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Examples
 How to drive a car, speak English, tie a
shoelace
Learned relatively slowly
Not flexible (used in specific ways)
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Amnesia
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Retrograde --declarative memory loss of prior
events
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Have trouble remembering from BEFORE brain
damage
Most likely to recover oldest memories
Most likely to lose ones nearer trauma
Does not affect procedural memory
(“Long kiss goodnight” -- many movies though rare)
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Amnesia
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Anterograde -- cannot form new declarative
memories
 Short-term memory is fine
 Does not affect procedural memory -- can even
learn some new skills
 (“Memento”)
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Often see confabulations to cover memory loss -- clue
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Several causes -- common one is thiamine deficiency
(long-term alcohol abuse -- Korsakoff’s syndrome)
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H.M.’s performance on mirror drawing
Three important points about memory
(of many that could be chosen)
(1) Memory is not the same as recollection.
Memory is critical for much that we do.
There are different types of memories that may be affected
by different manipulations, traumas, etc.
(2) Active, elaborative processing of information is important for
ensuring good retention of the information.
(3) The context match between when we learn something and
when we remember it has a large influence on how well we
remember.
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Readings and Key Terms
Bernstein et al. - Chapter 7, 224-250
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Iconic store
chunk
Interference: retroactive, proactive
Rehearsal: maintenance, elaborative
Context effects
Serial position curve: primacy, recency
Declarative and procedural memory
Retrograde and anterograde amnesia
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