Cassava

Available for over a year

Cassava roots are a vital source of calories in tropical countries. They are also a puzzle: cassava is highly toxic, and to be made safe it requires a tedious and complex preparation ritual. Plants such as cassava have routinely poisoned the unwary, and yet societies who are accustomed to it manage to make it safe despite all the hurdles. Tim Harford asks how humans have learned to do this without dropping dead. And what does cassava teach us about the hidden social forces that support a modern economy? Producer: Ben Crighton Editor: Richard Vadon