A casual reading of this abstract might give the wrong impression that intelligence is not necessary for achievement in chess. However, the actual results are that chess players, and even more, elite chess players have substantially higher intelligence than average. However, given that someone is a chess player, the researchers found that their ability, measured by a "chess test" or an international testing was not very significantly predicted by their general intelligence. Thus, we may say that intelligence seems to be a necessary pre-condition for chess achievement, but other factors tend to predict the chess ability of those who are intelligent enough to be good at chess.
Intelligence (online early)
Does chess need intelligence? — A study with young chess players
Merim Bilalić et al.
Although it is widely acknowledged that chess is the best example of an intellectual activity among games, evidence showing the association between any kind of intellectual ability and chess skill has been remarkably sparse. One of the reasons is that most of the studies investigated only one factor (e.g., intelligence), neglecting other factors relevant for the acquisition of chess skill (e.g., amount of practice, years of experience). The present study investigated the chess skill of 57 young chess players using measures of intelligence (WISC III), practice, and experience. Although practice had the most influence on chess skill, intelligence explained some variance even after the inclusion of practice. When an elite subsample of 23 children was tested, it turned out that intelligence was not a significant factor in chess skill, and that, if anything, it tended to correlate negatively with chess skill. This unexpected result is explained by a negative correlation between intelligence and practice in the elite subsample. The study demonstrates the dangers of focusing on a single factor in complex real-world situations where a number of closely interconnected factors operate.