In an experiment, we compare a group of 10-year-old chess experts with a group of 18-year-old chess amateurs. The 18-year0olds outperformed the 10-year-olds in a memory test on random numbers. But the 10-year-old chess experts did better than the 18-year-old chess amateurs when they are asked to recall the positions of the chess pieces on the board. This shows that the domain-specific knowledge is the main difference between the two groups which affect their cognitive abilities, but not the stages of cognitive development.…
