Behind Cadbury’s simian success was an unlikely inspiration: Daniel Kahneman, a psychologist who won a Nobel Prize in 2002 for showing that people are not the rational agents that economists had thought they were. He argues, most famously in “Thinking, Fast and Slow”, a 2011 book popularising his work, that the mind (human, that is, not gorilla) incorporates two systems: an intuitive “system one”, which makes many decisions automatically, and a calculating but lazy “system two”, which rationalises system one’s ideas and sometimes overrules them. For Mr Kahneman’s disciples advertising is above all a way to groom system one, to nudge consumers towards a buy.
