Filling Cabbies’ Heads with ‘The Knowledge’

December 11, 2011

In a post here, back in January 2010, I mentioned some research that had been done on London taxi drivers, who in order to be licensed have to master the (very) complex street layout of the city, and pass a demanding test called “The Knowledge“., a process that can take several years.  The research found that taxi drivers had visible differences in the brain structure known as the hippocampus, relative to the typical person.  That study, though, did not tease out the origin of the difference; in particular, it did not show whether the taxi drivers were different because of their work, or if people with the differing brain structure were more likely to succeed as taxi drivers.

Some new research has now shed some more light on this question, according to a post on the “Wired Science” blog at Wired.   In the new study, published in the most recent issue of Current Biology [abstract], two researchers from University College London, Eleanor Maguire and Katherine Woollett, tracked a group of 79 trainee cab drivers, and 31 control subjects.  At the beginning of the study, brain images taken of the participants showed no differences in structure, in the hippocampus or elsewhere.

Three to four years later, 39 of the original trainees had successfully acquired The Knowledge, while 40 had been unsuccessful.  Studies of the trainees’ brain structures at that point showed an increase in gray matter in the posterior hippocampus for the successful trainees.  Neither the unsuccessful trainees nor the control group showed any significant change.  It also appears, according to a press release from the Wellcome Trust,  which funded the research, that acquiring the new information and skills came at a price.

On the memory tasks, both qualified and non-qualified trainees were significantly better at memory tasks involving London landmarks than the control group. However, the qualified trainees – but not the trainees who failed to qualify – were worse at the other tasks, such as recalling complex visual information, than the controls.

It is still possible that the successful trainees had some inherent advantage that led to their success, but it does appear that the observed brain changes are directly related to the process of acquiring The Knowledge.  It is also not clear at this point just how the changes take place; however, this is another piece of evidence that the adult brain is. potentially,  considerably more malleable than was once thought — and that has to be good news for all of us geezers everywhere.

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