The Knowledge

Every London cabbie
      has a bigger one than you!

You have to have The Knowledge to drive a black cabLondon cabbies are renowned the world over for their skill, their courtesy, and perhaps most of all, for their intimate knowledge of the vast, sprawling city that is their workplace. Hardly surprising, since every cabbie working in London has passed The Knowledge, a very rigorous exam showing that they know the intricacies of the capital sufficiently well to take a fare from any specific place in London to anywhere else. They have to sit a written exam and a couple of one-to-one interviews, in which they are given imaginary journeys (well, the start and finish points anyway!), and they have to successfully describe the shortest route between the two.

Their answers have to be precise, and they can’t leave anything out. They even get marked down for hesitation! The test is so tough it often takes 12 attempts to pass it. Oh, and they also have to take a practical driving test too, but, well, you guessed that much, right?

London cabbies are generally an intelligent bunch, obviously – you can’t master a memory task like The Knowledge if you’re a slouch! One of them in particular went the extra mile though (sorry ’bout the pun) … Fred Housego became the 1980 winner of Mastermind, in front of 18 million television viewers. He subsequently made many TV appearances and became the host of an all-night radio phone-in show (on LBC, a London-based talk radio station) for many years during the 1990s.

This simple sign says you've learned The Knowledge!If you want to join the ranks of London’s cabbies, you’ll be trying to join the oldest taxi service in the world, launched in 1636 by King Charles I, who granted royal permission for 50 hackney carriages to ply their trade. But it was a Victorian police commissioner, Sir Richard Mayne, who instigated a standardised test back in the early 1850s. There had been a slew of complaints that cabbies didn’t really know where they were going during the Great Exhibition of 1851, and something obviously had to change, hence Sir Richard Mayne came up with what has become known as The Knowledge.

Studying The Knowledge

To gain a London cabbie’s license, a candidate has to memorise every one of approximately 25,000 streets, roads, avenues, courts, lanes, crescents, places, mews, yards, hills, and alleys that lie within a six-mile (9.6Km) radius of Charing Cross. It typically takes an entrant four or five years to earn the coveted green-and-white badge of a London cabbie. For most, that’s a year longer than it takes a student to gain a degree from Oxford.

And the examiner won’t just say “Take me from Finsbury Park tube station to the Bulgarian Embassy”, he’ll ask you to start from a street some distance from anything on one of the sample runs and drop him off at another equally obscure place. Mmm … they don’t make it easy, that’s for sure. And you thought the lists on this site presented quite a test of memory!  :~

They use every memory technique ever invented, and then some. There’s so much to remember, simple repetition would never be enough on its own. For example, they make liberal use of mnemonics, such as “Little apples grow quickly”, for the order of the theatres on Shaftesbury Avenue (Lyric, Apollo, Gielgud and Queen’s).

Learning The Knowledge represents a memory feat so intense that it physically alters the brains of those who manage to achieve that coveted cabbie’s badge. It’s been called the toughest geography test in the world, and no wonder. As well as all the streets, roads, avenues, etc, a would-be cabbie must also learn the locations of about 20,000 landmarks, or places of interest, including police stations, government buildings, embassies, churches, schools, guild halls, theatres, cinemas, railway stations, tube stations, hospitals, cemeteries, pubs, clubs, museums, parks, and monuments. It’s enough to make your head spin, and that’s not trying to memorise the whole thing, that’s just thinking about it!

In other words, any conceivable trip any fare-paying passenger might ask to be taken on, a cabbie has to be able to do it … from memory!

Memorising 320 routes, street by street …

The cabbie badge - that's what The Knowledge was leading up to!Also, to qualify, a cabbie must memorise well over 300 sample runs, street by street, so that nothing, absolutely nothing, presents them with a problem. When they’ve passed The Knowledge, believe me, they really have the knowledge. A fully licensed cabbie will know London so well that, if asked, he’ll be able to calculate the route between any two addresses anywhere inside the 113 square mile metropolitan area within seconds … from memory! That’s without looking at a map, and without turning on the sat-nav (huh, sat-nav?? don’t even mention such an infernal device to a cabbie!). And he should be able to list every street, every turn, every roundabout or junction of any kind on the trip, or even any roadworks that might present a problem. Now that’s what you call memory work!

But don’t think it’s so intense and esoteric that only a very few could manage such a prodigious feat. There are about 25,000 London cabbies, so though it’s undoubtedly tough, it’s definitely achievable (although only about 1 in 5 who start out ever make it to the finish line). Even so, they have to keep up with current events. Even a newly opened restaurant needs to be memorised, as well as any changes to the road system. If a public building undergoes any drastic changes or modernisations, or a new school opens, it all has to be slotted in with all the other knowledge every cabbie keeps stored safely inside his cranium.

How does learning The Knowledge affect the brain?

But what does this do to the brain? It makes it bigger, is the short answer! A study by neurologists at University College London showed that a London cabbie’s hippocampus is significantly larger than yours or mine. The hippocampus is the structure near the centre of the brain that deals with spatial navigation, and the intense memorisation undergone while learning The Knowledge literally makes it grow!

The hippocampus - where The Knowledge is stored!We speak of the hippocampus, but actually there are two distinct parts to the structure, one in the left hemisphere of the brain, the other in the right. The left part seems to be specifically ‘interested’ in words and language, while the right part is focused more on spatial memory, e.g. the layout of streets, as in The Knowledge. As well as these particular ‘interests’, the hippocampus plays a part in the formation of memories in general. The assertion that the hippocampus is actively engaged in spatial tasks has been backed up by fMRI scans, which showed that people have more active hippocampi when navigating correctly.

In the study, regular brain scans were taken of those studying for The Knowledge and they were compared to later scans, and to scans of a control group composed of people with no interest in becoming taxi drivers.

Regular practice equals more growth …

At first, there was no discernible difference, and everybody performed more or less the same on routine memory tests. Later on, as the study progressed, scans showed that the cabbies’ brains were literally growing, specifically in the region of the hippocampus. Furthermore, the longer they worked as cabbies, the bigger they grew!

Eleanor Maguire, who led the study, says

“We don’t know what is changing in the hippocampi of taxi drivers, whether it’s new neurons that are being produced, new connections between neurons, proliferation of other cell types, or all three.”

“There’s been a lot of research looking at trying to associate different brain areas with certain skills—musicians or linguists, for example,” she says. “The key point about London taxi drivers is that they acquire their navigational expertise when they’re adults, unlike musicians, who often start when children, and so there’s the added factor of the interaction between brain development and skill acquisition.”

It’s worth noting that cabbies come from all walks of life, and from widely varying backgrounds. It seems almost anyone can perform prodigious feats of memory, given enough practice and sufficient motivation.

Could regular memory work guard against Alzheimer’s?

It would be nice to able to report that, but it’s impossible to say. In Alzheimer’s, the hippocampus is one of the first structures to suffer damage. Maybe regular memory work, whether spatial or otherwise, could help safeguard against the disease, who knows? It’s certainly one way to keep your cognitive abilities sharp and clear, and it seems safe to assume the healthier and busier you manage to keep your brain, the better.

It’s also worth noting that when would-be cabbies are studying for The Knowledge, they physically go over the routes they’re trying to commit to memory. Riding around London by scooter is the preferred method, since they’re cheap to run and very manoeuvrable, but the main thing is that the student is physically interacting with the route; it seems an absolute necessity, rather than trying to learn the routes just from lists or handbooks. Nothing can take the place of physically seeing and travelling those routes. Worth remembering when you’re practising any memory work – you need to engage fully with your subject of study, involving as many of your senses as possible, in order to form detailed and long lasting memories.

Practice, practice, practice …

Every day a student of The Knowledge will probably recite at least 30 of the 320 runs he has been carefully memorising – every street, every turn, every junction. It’s this attention to detail, and this persistent practice, that forms strong and vivid memories, and results in total confidence in their abilities. In fact, they often get together and test each other, calling out the routes, street by street. This virtually endless repetition results in endelible memories, and the skill to ferry fare-paying passengers to literally any address in the city, with consummate ease.

We should all take a leaf out of their book; if we were to practise our memory work with the same devotion and the same level of motivation, who knows what we could achieve?


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