The science of chess

Science secret of grand masters revealed

The Nature Magazine article deals with the way in which chess experts gain the edge over opponents by falsifying their own ideas, while chess novices' optimism usually leads to a crushing defeat.

Cognitive scientist and chess player Michelle Cowley

In deciding which move to make, chess players mentally run through possible continuations of the game. Michelle Cowley, a cognitive scientist and keen chess player from Trinity College Dublin in Ireland, decided to study how different chess players decide whether their move strategies will be winners or losers.

Along with her colleague Ruth Byrne, she recruited 20 chess players, ranging from regular tournament players to a grandmaster. She presented each participant with six different chessboard positions from halfway through a game, where Black and White had equal chances of winning, and there was no immediately obvious next move.

Each player had to speak their thoughts aloud as they decided what move to make. Cowley scored the quality of the move sequences by comparing them with Fritz 8. She found that novices were more likely to convince themselves that bad moves would work out in their favour, because they focused more on the countermoves that would benefit their strategy while ignoring those that led to the downfall of their cherished hypotheses.

Conversely, masters tended to correctly predict when the eventual outcome of a move would weaken their position. "Grand masters think about what their opponents will do much more," says Byrne. "They tend to falsify their own hypotheses."

Falsification

Philosopher of Science Sir Karl Raimund Popper

This kind of hypothesis testing was called "falsification" by Sir Karl Raimund Popper, who is generally considered one of the greatest philosophers of the 20th century. Every genuine scientific theory, in Popper's view, can be tested and falsified, but never logically verified. It should not be inferred from the fact that a theory has withstood the most rigorous testing, for however long a period of time, that it has been verified; rather we should recognise that such a theory has received a high measure of corroboration. As such it may be provisionally retained as the best available theory – until it is finally falsified (if indeed it is ever falsified), and/or is superseded by a better theory.

But cognitive research, according to Cowley and Byrne, has shown that many people find falsification difficult. Until recently it was thought that scientists were the only group of experts that could be shown to use falsification routinely in their work. Now the two scientists have found that chess players, too, behave like good empirical scientists. Byrne speculates that this behaviour could be limited to those who are expert in their field. She thinks the ability to falsify is somehow linked to the vast database of knowledge that experts such as grandmasters – or scientists – accumulate. "People who know their area are more likely to look for ways that things can go wrong for them," she says.

Byrne and Cowley now hope to study developing chess players to find out how and when they develop falsification strategies. They also want to test chess masters in other activities that involve testing hypotheses – such as logic problems – to discover if their falsification skill is transferable.

Any volunteers?

• Click here for the full original Nature article
• Chess Masters' Hypothesis Testing (PDF of the Cowley and Byrne paper)