Skilled Memory Cognitive Psychology
Framework for the Analysis of Exceptional Memory
Verify that claimed skill exists
• Rigorous controlled evaluation of basic performance claims
• Studies of Expert-Novice "Differences"
• Training Experiments
Formulate Information Processing Model of Skill
Individual Difference Explanations of Skill
Skilled Memory Theory
(Chase and Ericsson, 1981, 1982)
Subjects generate long term memory encodings of presented information
Main Assumptions
• Encode presented information using knowledge and patterns
• Stored information is accessible via retrieval cues generated during initial encoding of material
• Encoded information stored in long term memory
• Speed of encoding improves with practice
• Memory skill is specific to particular materials
Recall Discussion of Mnemonics
Think of skilled memory as a collection of very well learned mnemonic techniques
Skilled Memory for Digits
Digit Span Task
Standard test of STM Capacity
Presented at 1 per second
Normal Range from 5 to 9 digits, high 15
SF, 80 digits
DD, 100 digits after hundreds of hours of practice
...420-799-810-6938-5802...
4,20: Then, ah, four twenty was a mile. I just said four twenty flat, that was easy enough, a good high school mile time.
799: Seven, nine, nine was an age. I said it was almost eight year old.
8,10: And eight 10 was a two mile time. I just said it’s a really fast two-mile.
69,38: Then sixty-nine, thirty-eight was a ten mile, and I just said it was up there, it was like a
really slow ten mile.
58,02 And then, ah, fifty-eight oh two was another ten mile and I said, OK. it’s almost fifty-eight minutes, it’s, it’s as good pace time mile...
Skilled Memory for Digits (Cont)
• Encode 3 or 4 digit sequences as running times, ages, dates
• Encoded information stored in long term memory
Evidence: Post session recall
• Speed of encoding improves as a function of practice
• Acquired skill is specific to particular materials
What happens if we give SF strings of digits that are very hard to encode as running times?
Description of JC (John Conrad)
Was a headwaiter at a restaurant in Boulder
Remembers complete dinner-orders of up to 20 people at several different tables without making use of pencil and paper
Motivated by larger tips, giving better service
No knowledge of memory literature
Started with tables of two people and worked up
Student at CU
No other exceptional memory skills
Laboratory analog of taking dinner orders in a restaurant
Method
Experiment is a series of 1 to 2 hour sessions
Session is a series of 6 to 12 trials
Trial
Consisted of memorizing and recalling dinner-orders of 3, 5, or 8 customers
PGP lays out cards containing pictures of people cut out from local newspapers
Orders were presented in fixed sequence starting with an initial customer and proceeding clockwise around arrangement of faces simulating a table.
JC initiated presentation of each order
Read at 1 second rate by PGP
JC could review all or part of previously presented orders
Recall items in any order
Materials
Orders were randomly generated by a computer program
Items occurred in fixed sequence:
entree, temperature, salad dressing, and starch
Materials
Entree / Temp / Salad Dress / StarchesSteak Oscar / Well-Done / Bleu Cheese / Fries
Sirloin Brochette / Med-Well / French / Baked
Potato
Filet Mignon / Medium / Oil and Vinegar / Rice
Rib Eye / Med-Rare / Thousand Island
Bar-B-Que / Rare
Boulder Steak
Model Of Skilled Memory for Dinner Orders
Model inferred from concurrent and retrospective verbal protocols
• Order are blocked in groups of four (or five) study
• Rehearse first four orders to develop well integrated retrieval structure
• Start over and deal with second four orders
Represent orders in a matrix organization
Order / Cust. 1 / Cust. 2 / Cust. 3 / Cust. 4Stake / Oscar / Filet / Rib Eye / BB
Temperature / Rare / Med-R. / Med. / Med-W
Salad Dress. / B / O / O / T
Starch / Baker / Baker / Fries / Fries
Specialized encoding process for each category
• Salad dressings were encoded by their first letter
• Temperatures were encoded as a spatial pattern
• Starches encoded as serial patterns
• Entrees were the most variable
Experiments
Comparison of JC with Untrained Subjects
Very large differences in study times and errors
Order of Recall
Novices recall by presented order
JC by Category
Standard model for free recall accounts for Novices
Effects of Verbalization
Very Small
Study-Times for Individual Orders
JC pattern provides strong support for model
Is JC's Memory Skill an Instance of Skilled Memory?
Long-Term Memory as Evidenced by Post-Session Recall
Recall 80% of orders from work the night before
Cued vs uncued recall
Interference effects
Improvement in Performance During the Year-Long Experiment
At start, Table of 8, 180 sec
After 1 year, Table of 8, 90 sec
The Category Presentation Experiment
Method
Five sessions, six trials each, tables of 3, 5, and 8 customers
Control condition
Category presentations condition by category
Tables of 8 broken up into blocks of 4
Results: NO DIFFERENCES
Varied Presentation Order Experiment
Method
Five sessions, six trials each, tables of 3, 5, and 8 customers
Control condition
Varied presentation condition
Randomly presented complete dinner orders
Note: JC had to deal with this condition at work
Results: Slow down on Tables of eight
Generalizability and Transfer of Memory Skill
The Category Materials Experiment
Materials
same structural characteristics as the dinner-orders
entrees were matched with animal names
temperatures were matched with times
salad dressings matched with flower names
starches matched with metals
Results: slower with animal list; lots of transfer
Degree of Transfer for Other Materials
Comparison with Novices
Practice effects
Basis for the generality of JC's memory skills
large number of subskills
material specific encoding strategies
adaptations to variations in presentation order
sophisticated understanding of his own memory structures
Other Demonstrations of Skilled Memory
Mental Multiplication
Special Strategies
Math Facts
products of all combinations of two digit
numbers
special patterns of numbers
Good post session recall
Novices verses Experts
Chess
Medical diagnosis
Bridge
Baseball
Page XXX