Winners of the Nobel prize in economics tend to sprinkle their papers with equations. Daniel Kahneman, who died on March 27th, populated his best-known work with characters and conundrums. Early readers encountered a schoolchild with an IQ of 150 in a city where the average was 100. Later they pondered the unfortunate Mr Tees, who arrived at the airport 30 minutes after his flight’s scheduled departure, and must have felt even worse when he discovered the plane had left 25 minutes late. In the 1970s readers had to evaluate ways to fight a disease that threatened to kill 600 people. In 1983 they were asked to guess the job of Linda, an outspoken, single 31-year-old philosophy graduate.