38 THE MIND'S EYE Which weighs more, a pound of feathers or a pound of lead? Everyone knows the answer: they both weigh the same. An interesting point, however, is what sort of image popped into your head when you read those words. One person who answered this question saw, distinctly, a pair of scales with a cube of lead on one scale balancing a big mound of feathers on the other. A second person got no mental image, but simply conceived of the problem in terms of words. People differ greatly in their power to "make pictures in their heads." Years ago the British scientist Sir Francis Galton asked a group of colleagues to try to visualize the breakfast table as they had sat down to eat that morning. Some of them saw the table in sharp detail and in colour. Others saw it only in black and white. Still others saw a blurred outline, as if through a badly adjusted magic lantern. Many could get no visual image at all. Scientists believe that most people are born with the ability to summon up in the mind's eye precise visual images of past experiences, but that many of us lose this power as we grow up, simply because we fail to exercise it.
