Where does chess reside? The collateral sulci host cognitive expertise

Despite being faced with literally millions of possibilities, the best chess players manage to find appropriate solutions even under limited thinking time. Here we elaborate on the mechanism behind their superior performance using behavioural, physiological, and neuroimaging evidence. Expert and novice chess players solved a chess task where they had to count particular pieces, and control non-chess tasks where they had to count all pieces on the board. While experts could utilise their knowledge in the chess task which resulted in a highly focused eye movement strategies and fast reaction times, there were no differences between experts and novices in the control non-chess task. Crucially, we find that the collateral sulci were not only more activated in experts than in novices when they dealt with chess tasks, but that also they were differently sensitive to the meaningfulness of stimuli. When experts could use their knowledge in normal game positions, the collateral sulci were more activated than when the use was limited through randomization of pieces on the board. These differences were absent in a non-chess control task, which indicates that the collateral sulcus is the brain structure behind chess experts’ superior performance