Using Analogies to Solve Problems • 343Once they determined that analogies can help with problem solving, but that hints
are required to help participants notice the presence of the source problem, Gick and
Holyoak (1983) proceeded to look for factors that help facilitate the noticing and map-
ping steps. One thing that makes noticing diffi cult is that people often focus on surface
features, specifi c elements that make up the problem, such as the rays and the tumor.
Surface features of the source problem and the target problem can be very different.
For example, there is a big difference between a tumor and a fortress, and between rays
and marching soldiers.
To test the idea that making the surface features more similar might help partici-
pants notice the relationship between the source story and the target story, Holyoak
and Kyunghee Koh (1987) created a problem that had surface features similar to the
radiation problem.Eff ect of Making Surface Features More Similar The lightbulb problem is a problem
with surface features similar to the radiation problem. The following is a shortened
version of this problem.Lightbulb Problem
In a physics lab at a major university, a very expensive lightbulb, which would emit pre-
cisely controlled quantities of light, was being used in some experiments. One morning
Ruth, the research assistant, came into the lab and found that the lightbulb no longer
worked. She noticed that the fi lament inside the bulb had broken into two parts. The sur-
rounding glass bulb was completely sealed, so there was no way to open it. Ruth knew
that the lightbulb could be repaired if a brief, high-intensity laser beam could be used to
fuse the two parts of the fi lament into one.
However, a high-intensity laser beam would also break the fragile glass surround-
ing the fi lament. At lower intensities the laser would not break the glass, but neither
would it fuse the fi lament. What type of procedure might be used to fuse the fi la-
ment with the laser and at the same time avoid breaking the glass? (adapted from
Holyoak & Koh, 1987)Holyoak and Koh (1987) used the radiation problem as the source problem and
the lightbulb problem as the target problem. Participants in one group were taught
about the radiation problem and its solution in an introductory psychology class, just
prior to being given the lightbulb problem. Participants in the control group did not
know about the radiation problem. The result was that 81 percent of participants who
knew about the radiation problem solved the lightbulb problem, but only 10 percent
of the participants in the control group solved it. Holyoak and Koh hypothesized that
this excellent analogical transfer from the radiation problem to the lightbulb problem
occurred because of the high surface similarity between rays (radiation problem) and
lasers (lightbulb problem).Eff ect of Varying the Structural Features Having determined that similar surface
features enhanced analogical transfer, Holyoak and Koh did another experiment in
which they investigated the effect of varying the structural features of the problem.
Structural features are the underlying principle that governs the solution. In the light-
bulb and radiation problems the structural features are similar: (a) weak laser beams
are used to avoid breaking the glass bulb (lightbulb problem); (b) weak rays are used to
avoid damaging healthy tissue (radiation problem).
Holyoak and Koh kept surface features constant by using the lightbulb problem as
the source problem and the radiation problem as the target problem, and varied struc-
ture by presenting two versions of the lightbulb problem. Both versions began with the
story about the broken fi lament surrounded by glass, and the information that the fi la-
ment could be repaired by fusing it with a high-intensity laser beam. But the problem
that needed to be solved in order to fi x the fi lament was different in the two versions.
The fi rst version, called the fragile-glass version, was essentially the same as the original
lightbulb problem. In this version, the structural features of the lightbulb and radiation
problems were similar.Copyright 2011 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part.