Skill Learning and Expertise

Anderson’s 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

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 of alphabet arithmetic problems as a function of stage of practice and size of addendum (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

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 to notice meaningful patterns –Chess masters excel in their recall of the clusters of pieces that they see. –Programmers can recall key programming language words in meaningful clusters. top-down processes -- giving meaning to what it is we see (Chi, Glaser, and Farr, 1988)

See anything unusual? Experts need only a few seconds to see what is wrong (or what isn’t) Experts augment these incomplete images with extensive background information (collapse of the upper right lobe, upper left in picture) (normal)

Chess Studies De Groot (1965) Instructed 5 chess grandmasters to think out loud Grandmasters only considered about 30 moves and only thought 6 moves ahead. Not that different from novices. However, masters spend more time on good moves. Masters rely on extensive experience: 50,000 patterns

Chase & Simon (1973)

Actual Board Position

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 ….. Normal digit span = 7 or 8 digits (phone number). Encoding strategies help ….. P140 number of this class P192 another number of this class Room number for class

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)

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

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

The Power Law of Practice The more practice, the easier a task becomes. How does a skill improve over time? Ubiquitous finding: skill improves as power function of amount of practice Amount of practice Time to complete task Log( Amount of practice ) Log( Time to complete task ) Time to complete task Amount of Practice 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)

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