short-term memory kimberley clow [email protected]
TRANSCRIPT
Outline
What is Memory?StructureSTM vs. LTM
Capacity of STM
ForgettingDecay vs. Interference
Structure of STM
What Is Memory?
Two different types of memoryShort-Term MemoryLong-Term Memory
Important TermsStructureEncodingRetrievalForgetting
What is the Structure?
Atkinson & Shiffrin Modal Model or Multi-Store ModelModal Model or Multi-Store Model
What Words?1. drum2. curtain3. bell4. coffee5. school6. parent7. moon8. garden9. hat10. farmer11. nose12. turkey13. colour14. house15. river
quite good recall
bad recall
best recall
Serial Position CurveSerial Position Curve%
rec
alle
d
position of word in list
5th 10th 15th
100 Primacy Effect (quite good recall)
Recency Effect (best recall)
Asymptote (bad recall)
Primacy & Recency
IQ
Word frequency
Delay
Distraction
Low frequency
Low IQ
distracter task
10 sec delay
Neurological Evidence
CWProblems with short-term memory
Anterograde amnesia
HMShort-term memory was goodProblems with long-term memory
KFShort-term memory impaired
Span of apprehension was 1 item
Short-Term Memory
What is Short-Term Memory?The information that is in consciousness
right nowThe limited-capacity memory
component for temporary information storage and manipulation
The mental workplace for retrieval and use of already known information
The Magical Number 7 (± 2)
“My problem is that I have been persecuted by an integer. For seven years this number has followed me around, has intruded in my most private data, and has assaulted me from the pages of our most public journals.
This number assumes a variety of disguises, being sometimes a little larger and sometimes a little smaller than usual, but never changing so much as to be unrecognizable…
Either there really is something unusual about the number or else I am suffering from delusions of persecution.”
Capacity of STM
How can we function on such a small short-term memory capacity?
Techniques that aid memoryRehearsal
Eases transfer to LTMMnemonic Devices
Strategies for increasing STM capacity
Chunking
IFYOUGROUPTOGETHERYOUREMEMBERBETTER
Which is Easier?
CHJ MLK ODW
Which is Easier?
FBI PHD IBM
Which is Easier?
AFGHANISTANVENEZUELANICARAGUA
Which is Easier?
CUBA
MALTA
GREECE
Individual Differences
Mnemonic Differences Novice vs. Expert
What About Forgetting?
The Brown-Peterson Task
Forget the letters very quickly
70% accuracy after 3 s 10% accuracy after 15 s
Concluded that items decay out of short term memory very quickly
Decay vs. Interference
Two reasons why we may forget things Decay
Information fades from memory
Not influenced by other information
Interference Other information disrupts
learning Proactive Interference Retroactive Interference
Probe Digit Task
Release From PI
Probe Digit Task Results due to # of items,
not time Interference NOT decay
Brown-Peterson results probably due to proactive interference of past trials
Is there a way to eliminate proactive interference?
Searching STM
Sternberg Shown a string of characters (1-6)
53427
Then a single character appears (probe) 7
Was the probe in the string? Measure speed of response depending upon…
How many characters were presented The sequential position of the probed character Whether the answer was yes or no
3 Possible Search Patterns
What Info Is in Memory?
VerbalConfuse E with D (auditory information)
Not E with F (visual information)
SemanticRelease from proactive interference (PI)
Changing categories is semantic info
VisualMental rotation tasks
Mental Rotation Task
Which of the three objects below matches the standard?
Baddeley’s Working-Memory
Evidence
Remember a string of 6 numbers or letters
Simultaneously do a reasoning taskShown stimuli like “AB”Then asked a true or false question
A precedes B B precedes AB is preceded by A A is preceded by BB does not precede A A does not precede BA is not preceded by B B is not preceded by A
Evidence
Test for limited resources & visual memory Verbal task or
spatial task Verbal response or
spatial response
Yes Yes
NoNo
No
NoNo
YesYes
Visual response competes with resources of visuo-spatial sketchpad
Summary
Short-term memory is limited in capacity Decay vs. Interference
Short-term memory is where information is consciously manipulated Rehearse to maintain information temporarily or to
transfer to long-term memory Workbench for manipulating current conscious
information
Short-term memory specializes in verbal and visuo-spatial information