“If they see me planting too much cocoa, they'll do things to my land and my family, and they won't bear fruit; really bad things; puripuri and other witchcraft.”

This was how Peter explained to me why he had only cultivated half of the 3 ha block the Papua New Guinean government had given him after he was evacuated from his home during a volcanic eruption eight years earlier. He was also providing a response to an accusation I had often heard levelled at his fellow villagers by government officials and development workers in the course of my anthropological field research: that the people were lazy or stupid because, like Peter, none had planted the whole of their blocks of land.

Such an avoidance of profit maximisation might have appeared economically irrational. But from the perspective of those villagers, putting in extra work just to make oneself a target for the jealousy of one's neighbours would be highly irrational behaviour.