Introduction

This chapter discusses the issues of similarity and analogy in development, learning, and instruction as represented in the chapters by John Bransford, Jeffery Franks, Nancy Vye, and Robert Sherwood; Ann Brown; Brian Ross; Rand Spiro, Paul Feltovich, Richard Coulson, and Daniel Anderson; and Stella Vosniadou. The following anecdote illustrates many of the themes that appear in the discussion of these chapters.

I was in a seminar recently where we were trying to set up an overhead projector for the first time. There was no screen in the room, and the one patch of wall of reasonable size was crossed with pipes. So I said to one of the other faculty members, “Let's try aiming the projector at the blackboard.” This individual said, “No, that's crazy.” I immediately gave in and began helping to aim the projector toward the wall. Then I said, “Wait, let's try the blackboard – I think it will work”. We did try the blackboard, and it did work reasonably well.

What was going on here? First, why did the other person immediately reject my original suggestion, and why did I give in? I think it is clear that the other person had a causal model for light which included the assumption that black surfaces absorb all the light that falls on them. As applied to the example at hand, this meant that it would be stupid to try to project the overhead on the blackboard, since no light would reflect off it and we would not be able to see the transparencies.