Biology students try to remember whether reptiles lay eggs or not. Biology teachers think in terms of the grand system of animal taxonomy. Novices perceive concrete details as concrete details. Experts perceive concrete details as symbols of patterns and insights that they have learned through years of experience. And, because they are capable of seeing a higher level of insight, they naturally want to talk on a higher level. They want to talk about chess strategies, not about bishops moving diagonally.
