Some ideas are simple (a rusty colander becoming a hanging garden planter), while others are downright feats (how to convert an old diesel car to run on vegetable oil).
The reason why economists in the late 19th century and much of the 20th put the rational utility-maximising individual at the heart of their models was not that they thought that economics should avoid looking into the brain, but because they lacked the technical means to do so, says Mr Colander.