Chess player

The play of a great chess player is qualitatively different from the play of a merely accomplished one. The great player sees the board differently, he processes information differently, and he recognizes meaningful patterns almost instantly. If you show a chess expert and an amateur a board with a chess game in progress on it, the expert will be able to re-create from memory the layout of the entire game. The amateur won't. Yet, if you show that same expert a board with chess pieces irregularly and haphazardly placed on it, he will not be able to re-create the layout. This demonstrates how thoroughly chess is imprinted on the minds of succesful players. But it also shows , how limited the scope of their expertise is.

Source: Wisdom of crowds, page 32.