Those who doubt that there is something going on in the world of ideas should get themselves a publisher’s catalogue. One month there is a book called Nudge, the next a book called Sway. A volume called Predictably Irrational follows another called Irrationality. Since the success of Malcolm Gladwell’s Tipping Point, books on tipping points have reached a tipping point.

Behind this publishing explosion, with its PR hoopla, is real and solid intellectual progress. It comes from two streams of thought, developing alongside each other. The first is the idea of evolutionary psychology… The second stream of thought is behavioural economics. For twenty years now, some economists have been looking at the psychology of economic decision-making. Instead of seeing humans as rational calculating machines, behavioural economists have been conducting experiments to assess how real choices are made…” (Times of London)