Cognitive Psychology: Connecting Mind, Research and Everyday Experience, 3rd Edition

344 • CHAPTER 12 Problem Solving

Fragile-Glass Version

(Source and target problems have similar

structural features)

Problem: A high-intensity laser beam would break the fragile glass surrounding the fi la-

ment. At lower intensities the laser would not break the glass, but neither would it fuse

the fi lament.

Ruth’s solution: Ruth placed several lasers in a circle around the lightbulb and administered

low-intensity laser beams from several directions all at once. The beams all converged on the

fi lament, where their combined effect was enough to fuse it. Because each spot on the sur-

rounding glass received only a low-intensity beam from each laser, the glass was left intact.

The structural features of this problem are similar to the structural features of the

radiation problem, as indicated in the far right column of Table 12.2. Sixty-nine percent

of the participants who read this solution were able to solve the radiation problem.

In the second version of the problem, called the insuffi cient-intensity version, the

structural features of the lightbulb and radiation problems are different.

Insufficient-Intensity Version

(Source and target problems have different

structural features)

Problem: The laser generated only low-intensity beams that were not strong enough to

fuse the fi lament. A much more intense laser beam was needed.

Ruth’s solution: Ruth placed several lasers in a circle around the lightbulb and admin-

istered low-intensity laser beams from several directions all at once. The beams all con-

verged on the fi lament, where their combined effect was enough to fuse it.

The structural features of this problem are different from the structural features of the

radiation problem, as indicated in the far right column of Table 12.3. Only 33 percent

of the participants who read this solution were able to solve the radiation problem. The

conclusion from comparing the results from these two versions of the lightbulb prob-

lem is that analogical transfer is better when the structural features of the source and

target problems are more similar.

All of these experiments taken together show that transfer is aided by making

surface features more similar and by making structural features more similar. But the

fact remains that it is often diffi cult for people to apply analogies to solving problems,

especially in situations in which surface and structural similarities are not as obvious

as in the lightbulb and radiation problems. One way to help people notice structural

similarities is through a training procedure called analogical encoding.

Encoding Specificity

Dedre Gentner and Susan Goldin-Meadow (2003) have shown that it is possible to

get people to discover similar structural features by using a technique called analogical

encoding, in which participants compare two cases that illustrate a principle. The idea

behind analogical encoding is that when learners compare cases, they become more

likely to see the underlying structure.

TABLE 12.2 Fragile-Glass Condition: Structural Features Similar

Problems Surface Features Structural Features

Source problem: Fragile-glass version

of lightbulb problem: Glass will break

if laser is too strong.

Laser beam and

fi lament

Need high-intensity radiation to fi x

fi lament without damaging surrounding

glass with a high intensity beam.

Target problem: Radiation problem Rays and tumor Need high-intensity radiation to fi x

tumor without damaging surrounding

body with a high-intensity beam.

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