The Knowledge Helps London Taxi Drivers Grow Grey Matter

Who says you can’t teach an old dog new tricks? Or an adult human for that matter. New research from England shows that not only can we learn throughout our lives but that learning can change the structure of our brains as well.

Eleanor Maguire from the Wellcome Trust Centre for Neuroimaging at University College London took adults training for the toughest taxi job and watched how their brains changed as they learned the ins and outs of London over four years.

For those that don’t know, The Knowledge is the test given to all taxi drivers in London who are licensed to drive the famous black cabs. But this is no ordinary test. It is perhaps the biggest spatial memory test available.

To get a taxi license to drive in all of London, drivers must know all 25,000 streets within a six-mile radius of Charing Cross, the spot known as the center of London. They must also know the locations of 20,000 landmarks and know the shortest routes to get from point to point.

According to Dr. Maguire’s research all of this acquired knowledge increases the size of the hippocampus, the region of the brain associated with memory.

Professor Maguire and her colleague Dr. Katherine Woollett followed a group of 79 trainee taxi drivers and 31 controls (non-taxi drivers). Periodically they took snapshots of their brain structure over time using magnetic resonance imaging (MRI) and studying their performance on certain memory tasks.

Only 39 of the group passed the tests and went on to qualify as taxi drivers, which is about the norm for given the difficulty of The Knowledge.

By looking at the structure of the brain, the neuroscientists saw remarkable changes in the brain structure of the 39 who passed the taxi driver test. They saw an increase in grey matter — the nerve cells in the brain where processing takes place — in the posterior hippocampus.

Dr. Maguire says, “The human brain remains ‘plastic’, even in adult life, allowing it to adapt when we learn new tasks.”

But The Knowledge may come at a price. Besides the 3-4-year study period where prospective drivers say they lost touch with friends, ignored holidays and had no social life, this research which appears in the journal Current Biology found that though at the end of the training, those who pass The Knowledge have an imprinted map of London in their heads, they tend to have a weaker complex visual memory.

This study supports increasing evidence that learning can help our brains grow even into adulthood. This is encouraging news for lifelong learning and the potential for rehabilitation after brain damage.