The Sense of Style: The Thinking Person's Guide to Writing in the 21st Century

by Steven Pinker

as we become familiar with something, we think about it more in terms of the use we put it to and less in terms of what it looks like and what it is made of. This transition, another staple of the cognitive psychology curriculum, is called functional fixity (sometimes functional fixedness).24 In the textbook experiment, people are given a candle, a book of matches, and a box of thumbtacks, and are asked to attach the candle to the wall so that the wax won’t drip onto the floor. The solution is to dump the thumbtacks out of the box, tack the box to the wall, and stick the candle onto the box. Most people never figure this out because they think of the box as a container for the tacks rather than a physical object in its own right, with handy features like a flat surface and perpendicular sides. The blind spot is called functional fixity because people get fixated on an object’s function and forget its physical makeup.