Gem stone cowboys

THE discovery of the “world’s biggest diamond” in 2007 sent ripples of excitement around the world. It was said to be twice the size of the previous record holder, the Cullinan, or Great Star of Africa, discovered near Pretoria in 1905.

The “diamond” was discovered in a mine in South Africa’s North West.

Brett Jolly, a spokesman for the mining firm Two Point Five Construction, had announced the stone was being transported to a bank vault in Johannesburg “until we calm down and decide what we are going to do”.

But its status was shortlived.

Days later, the president of the World Federation of Diamond Bourses, Ernest Blom, announced he was withdrawing from the verification process to test the stone, saying: “I suspect something is afoot.”

Jolly, originally a British property developer, claimed he had been the victim of a fraud to entice him to buy the land.

He told the website Mining Weekly Online that he wished he “never was involved with [the diamond] in the first place”, adding that he didn’t “care any more whether it’s a diamond or not”.

Meanwhile, De Beers, which owns the Cullinan, expressed relief that it still holds the title of the biggest diamond ever discovered. “The search for diamonds is so romantic,” said a spokesman, Tom Tweedy. “This does illustrate that diamonds hold a mystique with people.”

Why do we fall for fake news?

HUMANS like to think of themselves as rational creatures, but most of the time we are guided by emotional and irrational thinking.

Psychologists have shown this through the study of cognitive shortcuts known as heuristics. It’s hard to imagine getting through so much as a trip to the supermarket without these time-savers.

“You don’t and can’t take the time and energy to examine and compare every brand of yoghurt,” says Wray Herbert, author of On Second Thought: Outsmarting Your Mind’s Hard-Wired Habits. So we might instead rely on what is known as the familiarity heuristic, our tendency to assume that if something is familiar, it must be good and safe.

US cognitive scientist David Rand illustrated our tendency to believe things we’ve been exposed to in the past.

His study presented subjects with headlines – some false, some true – in a format identical to what users see on Facebook.

Rand found that simply being exposed to fake news made people more likely to rate those stories as accurate later on in the experiment.

If you’ve seen something before, “your brain subconsciously uses that as an indication that it’s true”, he said.