Que Hace a Un Experto Experto

8/21/2019 Que Hace a Un Experto Experto

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Skill Learning and Expertise

Andersons ACT Theory

General theory of learning and problem solving

Anderson (e.g., 1983, 1990, 1993, 1996)

Adaptive Control of Thought (ACT)

Various forms: ACT*, ACT-R

Rely on notion of production systems

A schematic diagram of the major components

If information in working memory matches production rule condition, then

fire production rule


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Skill Learning in ACT

Theory claims that cognitive skills are realized by

production rules

Knowledge initially enters in declarative form

e.g., instructions for how to drive a car

Transformed into procedural knowledge

e.g., skilled driving

Speed of solution ofalphabet arithmeticproblems as afunction of stage ofpractice and size ofaddendum (add 2,3, or 4).

Data from Zbrodoff(1995).

Developing Expertise

What are differences between novices and experts?

How to become an expert?

Speed of learning


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Experts excel mainly in their own domains

experts are masters in their own domain

the skill does not cross into different domains

(Chi, Glaser, and Farr, 1988; Ericsson and Charness, 1997)

Experts perceive large meaningful patterns

in their domain

Experts have extensive knowledge. Allows them tonotice meaningful patterns

Chess masters excel in their recall of the clusters ofpieces that they see.

Programmers can recall key programming languagewords in meaningful clusters.

top-down processes -- giving meaning to what it is wesee

(Chi, Glaser, and Farr, 1988)

See anything unusual?

Experts need only a few seconds to see what is

wrong (or what isnt)

Experts augment these incomplete images with

extensive background information

(collapseoftheupperrightlobe,upperleftinpicture)(normal)


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Chess Studies

De Groot (1965)

Instructed 5 chess grandmasters to think out loud

Grandmasters only considered about 30 moves and onlythought 6 moves ahead.

Not that different from novices. However, masters spendmore time on good moves.

Masters rely on extensive experience: 50,000 patterns

Chase & Simon (1973)

Actual Board Position


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Random Board Position

Conclusion from Chase & Simon (1973)

Chess masters only expert with real chess positions.

They do not have better memory in general

Expertise allows chunking of salient information to

promote memory of good moves

Experts organize knowledge differently reflects a deep

understanding.

Increasing Your Digit Span

Number of digits that can be repeated after one presentation

1 4 0 1 9 2 1 0 1 ..

Normal digit span = 7 or 8 digits (phone number). Encoding

strategies help

1 4 0 1 9 2 1 0 1 ..

P140

number of

this class

P192 another

number of

this class

Room

number for

class


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Growth in memory span for one subject (S.F.) with practice

Memory span for digits can be trained

you too can have a 80 digit memory span

Experts see and represent a problem in their

own domain at a deeper level than novices

Experts see structural similarities

Novices see surface similarity

(Chi, Glaser, and Farr, 1988)

Novices group these

Experts group these

Chi, Feltovich, and Glaser, 1981)


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What makes an expert an expert?

Talent? IQ? Practice? Genetic factors?

Study exceptional feats:

Memory experts

Chess experts

Musicians

Athletes

General & Inherited Factors

IQ tests*

Short-term memory

Speed of reading

Reasoning ability

Attention

Do not predict

superior performance in a

particular domain

Experts are not better problem solvers in general. Expertise

is domain specific

* IQ tests might predict some success in high-complexity jobs (e.g. scientist)

10 year rule

10 years of deliberate practice needed to attain an

international level: not simply engaging in activity, but

practicing in an effortful, intensive, self-monitored mode

Master chess players spend 10,000 20,000 hours

playing


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What about talent?

Maybe exceptional performance in some area can be

explained by talent an innate predisposition that

predetermines performance in a domain.

Anders Ericsson et al.

disagree that concept of talent is useful or explains

anything

(genius is 90% perspiration and 10% inspiration)

this is controversial!

What about musical talent?

Absolute pitch:

Most musicians acquired it for their own instruments

Can be improved by training

Difference between good and exceptional musicians is

related to the amount of practice

Graph from Ericsson et al. (1996) showing the cumulative amount of practice by

two groups of aspiring musical performers (experts and good violinists) and those

who planned to teach music


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The Power Law of Practice

The more practice, the easier a task becomes. Howdoes a skill improve over time?

Ubiquitous finding: skill improves as power function ofamount of practice

aT cP=

Amount of practice

Timetocompletetask

Log( Amount of practice )

Log(Timetocompletetask)

Time tocomplete task

Amount ofPractice

Constant

(Slope)

constant

Cigar rolling ability over

10 years of working in a factory

Initial large

improvements

decrease with time

Very difficult to

improve any further

power law of

practice

(Crossman, 1959)

Learning to Mirror Reverse Read

(Kolers, 1979)


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(Kolers, 1979)

Practice increased brain size

Hippocampus & London Taxi Drivers

Brain scans reveal that taxi drivers have much larger

posterior hippocampus than controls

Maguire et al. 2000

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