I read an article in the paper about a study (several years ago) about directions. They were testing mice (rats?) in a maze that had symbols at various intersections. They would time how long it told the mice to complete the maze, over and over. Eventually, they would remove the symbols and retest the mice. They found that the male mice would do the maze in about the same amount of time as they did with the symbols, but the female mice would take longer. Their conclusion was that the female mice had learned "take a left at the triangle", but the male mice just learned at what point to take that left. So when the symbol was removed, the male mice knew where to take that left, because they had not paid any attention to the symbol, but the female mice were confused, because they relied on the triangle!