How People Learn:
Brain, Mind,
Experience, and School
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BOX 3.7
Flexible Transfer
College students were presented with the following passage about a
general and a fortress (Gick and Holyoak, 1980:309).
A general wishes to capture a fortress located in the center of a
country. There are many roads radiating outward from the fortress. All
have been mined so that while small groups of men can pass over the
roads safely, a large force will detonate the mines. A full-scale
direct attack is therefore impossible. The general's solution is to
divide his army into small groups, send each group to the head of a
different road, and have the groups converge simultaneously on the
fortress.
Students memorized the
information in the passage and were then asked to try another task,
which was to solve the following problem (Gick and Holyoak,
1980:307-308).
You are a doctor faced with a patient who has a malignant tumor in
his stomach. It is impossible to operate on the patient, but unless the
tumor is destroyed the patient will die. There is a kind of ray that
may be used to destroy the tumor. If the rays reach the tumor all at
once and with sufficiently high intensity, the tumor will be destroyed,
but surrounding tissue may be damaged as well. At lower intensities the
rays are harmless to healthy tissue, but they will not affect the tumor
either. What type of procedure might be used to destroy the tumor with
the rays, and at the same time avoid destroying the healthy tissue?
Few college students
were able to solve this problem when left to their own devices. However,
over 90 percent were able to solve the tumor problem when they were
explicitly told to use information about the general and the fortress to
help them. These students perceived the analogy between dividing the
troops into small units and using a number of small-dose rays that each
converge on the same point--the cancerous tissue. Each ray is too weak
to harm tissue except at the point of convergence. Despite the
relevance of the fortress problem to the tumor problem, the information
was not used spontaneously--the connection between the two sets of
information had to be explicitly pointed out.
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