Making the most of the obvious

James Surowiecki is a Martian. True, he doesn’t have pointy ears and he writes a financial column for the New Yorker. But only someone fallen to Earth would celebrate the obvious as much as he does. When he ventures out into a city, he marvels at the fact that fast-walking pedestrians don’t bump into each other on a crowded pavement. He calls it ‘the beauty of a well- co-ordinated crowd’. When he goes into a supermarket in search of orange juice, there’s the juice carton ready and waiting for him! How did the grocer know he was coming? And how does he know he’ll want some more juice tomorrow? He compares supermarket supply chains to the spontaneous movements of a flock of starlings. When he goes to the races, he is astonished that the favourite horse typically wins most of the time. How can crowds be so smart? But there is one failure of crowds which does dismay him and he’s not afraid to say so, in a chapter entitled ‘Traffic: What we have here is a Failure to Co-ordinate’. Martians know a lot about traffic jams: ‘Traffic jams, once created, are fairly stable and can move without major changes in their form for several hours against the flow of traffic.’ If only we all drove in strict formation and at the same distance from the car in front, traffic jams wouldn’t happen. They arrange things differently on Mars.

The weakness of Surowiecki’s rambling book (it would have worked better as a short essay in the New Yorker) is that he tries to turn a statistical truism into a sociological phenomenon. In 1906 a British social scientist, Francis Galton, calculated the simple average of 800 attempts to guess the weight of a dressed ox at a Plymouth fair.