If I asked you to visualize, say, Harry Potter, you'd probably have no problem picturing him in your mind: a teenage wizard with black hair, glasses, a thunderbolt-shaped scar on his forehead and a wand in his hand.

如果我让你想象一下哈利波特的样子，你大概能立刻在脑中构建出一个画像：一头黑发的十几岁巫师，戴着眼镜，脑门上有个闪电形疤，手里握着魔杖。