Since 1865, no cab driver in London has been able to omit “The Knowledge”. It requires the memorisation of 320 routes, an achievement that takes years, but has been made into a joke by the robot cars of the future. A flesh-and-blood cabby “interacts with people from all walks of life”, according to a brochure by Transport for London, and that’s “a lot more than just taking people from A to B”. Visually fascinating, Colson traces his interviewees’ mind maps of the city using the mapping technology of robot cars.