THESE are thrilling days for behavioural research. Every week seems to yield a new discovery about how bad people are at making decisions. Humans, it turns out, are impressionable, emotional and irrational. We buy things we don't need, often at arbitrary prices and for silly reasons. Studies show that when a store plays soothing music, shoppers will linger for longer and often spend more. If customers are in a good mood, they are more susceptible to persuasion. We believe price tends to indicate the value of things, not the other way around. And many people will squander valuable time to get something free.
