Quarter Mile Knowledge

Terrible traffic today in London: i ended up having to jump in a cab to get to a conference session, but reckon it would have been easier to walk. So plenty of time to talk to the cabbie. In London, drivers have ‘the Knowledge‘, a much researched and well known ability to navigate any route in town. But it’s not free knowledge: it’s hard earned.

Typically it takes a few years: you start on a bike, learning the main routes, then move on to progressively more complex and granular detail. The driver today, it took him five years to pass his tests (they ask you the route from A to B and you have to be able to recite every road, every turn, every name, from memory).

The process he described was fascinating: first learning the four hundred main ‘blue book’ routes across town, then doing his ‘quarter miles‘. That’s how he learnt: the city is split into quarter mile circles, and from each one, you memorise the set routes into and out of them. Over time, you work out how the Quarter Miles align with each other: you build that mental schema. Recent neuroimaging shows that the hippocampus, deep in the brain, is actually physically enlarged by this learning process.

I may not have the detail quite right: for him, it was a natural language, and as with many things that we know well, we are unable to articulate quite how we do them. But his best description, which he said he shared with other drivers, was that as he learned the Quarter Miles, the map of London collapsed: it squeezed inwards to just relate to the points where the circles touched. When i threw him a challenge, how to get from Waterloo to the British Museum, he rattled through a sequence of short bursts which, i guess, related to the Quarter Miles.

It’s a remarkably constructivist view of learning, although quite fascinating, especially when you hear it explained (i would encourage anyone in a London taxi to ask about the Knowledge: be prepared for a long journey).

Of course, in our world, there are few things so easily deconstructed into Quarter Miles. Instead, our frameworks tend to be more complex and fluid, but maybe there’s something familiar about that ‘collapsing in‘ of the map, as we learn something (like typing) it becomes subconscious, intuitive. Learnt.