January 10, 2011

The Learning Curve

Chapter 07: Cognition
from Psychology: An Introduction by Russ Dewey

The Learning Curve

With repetition of almost any motor task, learning occurs, and a person becomes more efficient or effective at carrying out a task. In the pursuit rotor tasks, time spent on the metal dot increases. In the mirror-tracing task, the tracing becomes more accurate. Progress in skill learning commonly follows an S-shaped curve, with some measure of skill on the Y axis and number of trials on the X-axis. Progress is slow at first, then a subject may experience a burst of learning that produces a rapid rise on the graph.

What is the shape of the usual learning curve? What did Fitts and Posner say about "plateaus" in motor learning?

Many people believe that plateaus or flat periods during which a skill does not improve normally punctuate learning curves. But the idea of a plateau as a temporary stagnant period followed by more learning is a myth. Fitts and Posner (1967) found gradual improvement with practice in almost all motor skills. They said flatly there were "no plateaus." Fred Keller of Harvard referred to the "phantom plateau" since one seldom occurred, but people believed that it did.



The S-shaped "learning curve" typical of complex learning

Why does an S-curve of growth eventually level off?

What people call a plateau may be a period of stability after a skill is learned as well as it can be learned. Most growth processes follow the same S-shaped curve as motor learning. In general. An S-shaped curve of growth levels off because stability is attained, a resource needed for growth is limited, or a ceiling of performance is reached. For example, mirror tracing cannot improve forever. Given enough time, one should become very good at it, then improvement in performance stops. This is a plateau of sorts, indicating maximum competence has been attained.

What phases of learning a complex skill cause the "S-curve" pattern?

The S-shaped learning curve is most obvious when someone learns a highly complex task. The initial part of the curve rises slowly as a person becomes familiar with basic components of a skill. The steep ascending phase occurs when there is enough experience with rudiments or simple components to start "putting it all together." Rapid progress follows until the skill "hits a ceiling" or stabilizes at a high level.

Why does a "steep learning curve" indicate easy learning? What do people mean when they use that term?

People often speak of a steep learning curve when they mean the opposite. A steep learning curve is one in which skill improves quickly, meaning something is easy to learn. However, what most people mean by "steep learning curve" is difficult learning experience. No doubt they are thinking of steep hills and steep mountains which make climbing difficult. In actuality, the steepest part of the learning curve is the portion where learning is fastest and easiest.
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