Present someone with something they find disgusting and they will invariably draw back in horror. This "yuk!" response is universal - as far as we know, all humans have it.
But, perhaps more surprisingly, what people consider disgusting varies considerably across cultures. Jellyfish, sheep eyes or live grubs can induce disgust or delight depending on what we're used to eating.
And there's another, even more intriguing side to disgust: it can influence our moral judgements about the person or object we see as disgusting. The Liverpool football player Luis Suarez was called disgusting for biting an opponent and received a major penalty, a ten match ban, as a result. Yet he did little damage and other footballers routinely get away with causing far more harm with little, if any, moral outrage. Suarez bit and the disgust his action induced in others arguably made him a moral deviant, potentially influencing the severe punishment.
The surprising psychology of disgust is the subject of this episode of The Human Zoo. It's presented by Michael Blastland, with the trusted guidance of Nick Chater, Professor of Behavioural Science at Warwick Business School.
Producer: Toby Murcott
A Pier production for BBC Radio 4.