He’d put a person in a room with two strings hanging from the ceiling. The task was to get ahold of both, but the strings were too far apart for the person to reach one while holding the other. There was a hammer in the room, though, which a few clever subjects realized they could tie to one of the strings, push away, and catch on the backswing while holding the other string. The thing was, subjects who first used the hammer for a few simple tasks involving nails suffered a diminished ability to realize that the hammer could be used as something else—as a weight to make a pendulum, for example. Context had reinforced familiarity, and familiarity had blinded them to new possibilities. (Location 525)
