Why chess teases the brain: Scientists check players' responses to complex problems

ANY chess player who misses a simple checkmate and wonders to himself 'How could I have overlooked anything so simple?' now has an answer to his dilemma: You weren't properly using the frontal lobe of your brain and the junction between the occipital and parietal lobes.

That is one of the conclusions of research conducted at the Cognitive Neuroscience Section of the Medical Neurology Branch of the National Institute of Neurological Disorders and Stroke in Bethesda, Maryland, and reported in today's issue of the science journal Nature.

The experiments conducted by Paolo Nichelli, Jordan Grafman and others, utilised the technique of positron emission tomography (PET) to scan the brains of experienced chess players and identify which parts were working when specific tasks were being carried out. PET scanning involves the emission of particles of anti-matter - positrons - which are neutralised by electrons, with energy released as they annihilate each other. Detectors pick up the location of such energy release and can thus identify electrical activity in the brain.

For the current experiment, subjects (10 right- handed tournament chess players) were presented with a series of slides of increasingly complex chess board positions and tasks. The first was black/white discrimination, in which the players was required simply to state whether pieces of a particular colour were on the board. They progressed via spatial discrimination (identifying the colour of the nearest chess piece to a square marked with an X), rule retrieval, to checkmate judgement.

The idea behind the experimental design was to separate out the components of a complex task. By identifying the parts of the brain responsible for black/white discrimination and subtracting them from the more complex picture of spatial discrimination, an idea may be obtained of the neural networks involved purely in the latter task.

To find a checkmate, the important action is centred on the occipital-parietal junction and the frontal lobe. Increased activity was also found in the left orbito-frontal cortex and right pre-frontal cortex. 'We believe these two regions of activation subserve managerial knowledge required for the planning and execution of endgame strategies,' researchers say.