Study points to air pollution decreasing chess player performance

On Jan. 26, researchers from Massachusetts Institute of Technology and Maastricht University published a paper titled “Indoor Air Quality and Strategic Decision Making.” The study focuses on comparing readings from air-quality monitors to the quality of 30,000 moves in a chess tournament.

The paper begins by discussing the importance of strategic decision-making in the workplace, problem-solving, and critical-thinking skills. The authors discuss the potential of air pollution negatively affecting cognitive performance. While a negative link has been theorized between air quality and strategic decision-making, there has previously been little experimental evidence that confirms this theory.

The data contains information on more than 30,000 moves from 121 chess players in 609 official matches in three official tournaments in Germany between 2017 and 2019. Each tournament was comprised of seven rounds that were played over a period of eight weeks. During this time, there were a number of fluctuations in the air quality, so the researchers had data spanning a variety of environments.

The researchers then analyzed all the moves that these players made using Stockfish, an open-source artificial intelligence chess engine. Stockfish evaluated all the moves that these players made and compared them against the “optimal” move that Stockfish would have made. This evaluation was completely independent of the player’s opponent and previous moves of the player. The players also had an incentive to perform well, so it was believed that players were performing what they considered to be the “best” move.

For measuring the air quality of the playing environment, the researchers installed three air quality sensors inside the tournament venue, which continuously recorded the environmental conditions. Their measure of air quality was based on the concentration of PM2.5, which is fine particulate matter smaller than 2.5 micrometers. PM2.5 can be inhaled and enter deep into the lungs and bloodstream, which introduces well-documented risks to the human body. This ultimately may affect performance or influence behavior, hence this study.

The study found that an increase in PM2.5 concentrations indoors significantly worsened the ability of chess players to select the optimal move. When PM2.5 concentrations increase by 10 micrograms per cubic meter (a significant deviation from normal), there was a 2.1 percent increase in players making a “meaningful” error. This corresponded to an increase of 26.3 percent relative to the average proportion of error in the researchers’ sample.

Additionally, the researchers were able to study the effects of PM2.5 concentrations when players were under time pressure. Chess players had a fixed amount of time allotted to them for their first 40 moves, and the effects of PM2.5 were found to be the most pronounced before the time control at move 40. This indicated to the researchers that poor air quality harms the performance of players when acting under time pressure. Another analysis revealed that weaker players were more affected by the poorer air quality.

As part of the study, the researchers documented the role of outdoor pollution in shaping indoor conditions. They concluded that variation in the indoor PM reflects the air pollution in the outdoor area surrounding the tournament site. Using this data, they found similar performance drops as they saw in their indoor measurements, which suggested the effects were a result of particulate pollution rather than other sources.

The researchers also performed a replication exercise in which they studied move-quality data from Chess Bundesliga, the top national chess league in Germany. They compared outdoor PM pollution measurements from 2003 to 2019 and found the same results: When there are more air pollutants, there is a significant and sizable increase in the likelihood of making “meaningful” mistakes, especially in the part of the game proceeding time control.

The researchers concluded that their findings have important implications for firms and policy. They stated that their results highlight the benefits of investing in building infrastructure to reduce PM concentrations. The researchers advise that this is especially important for improving the quality of strategic decisions made by high-skill workers under high levels of time stress.