(from P.A.Wozniak, Economics of Learning)
Narrowing by example is a very efficient way of making the question-related stimulus more specific and thus more successful in imprinting durable memories.
The concept of the price ceiling may be enhanced if a narrowing example of goods that might be subject to government imposed price ceiling is provided. Moreover, the example makes the definition of price ceiling more specific; hence the increased likelihood of diminished complexity of the synaptic pattern, and minimization of pattern extraction.
Q: What is the name of the price specified by the government above which goods cannot be sold (e.g. medications)?
A: price ceiling
In the example above, the phrases "(e.g. medications)" serves as the means of narrowing by example. Similarly, the illustration of competitive nature of pork versus beef helps narrowing by example in the definition of horizontal markets:
Q: What is the name of markets for products that can act as substitutes (e.g. pork and beef markets)?
A: horizontal markets
Note, that examples placed in
the answer field will often act in the opposite way than it is
the case above. The next section will discuss the various aspects
of information redundancy in knowledge representation. In that
context, the technique of extending by example will be presented.