If you've got lucky, it's easy to convince people you're a sage

"Expert" predictions only need a few lucky guesses, then everyone believes them.

LSE's Nattavudh Powdthavee and Nanyang University's Yohanes E. Riyanto presented a paper last month titled Why Do People Pay for Useless Advice? (pdf) The authors demonstrate that people are prepared to pay for investment advice which they know cannot possibly be based on any real evidence – provided the advisor has got things right in the past.

Participants in the experiment were told to bet on five consecutive rounds of coin flips (they could pick the stake, provided it was higher than a minimum level and wouldn't make them lose all their money before the last round). Since they were using a fair coin, the chance of heads or tails coming up each time was 50-50, and the chance of someone calling the correct flips in all five rounds is one in thirty two. More importantly, no amount of expertise can help one predict the outcome of a sequence of coin tosses.

So when the participants were offered the chance to buy "predictions", you would expect them to ignore them. And most of them did, at least for round one (although even then, around 15 per cent of them did pay). But after the first round of tosses, everyone got to see their predictions, even those who hadn't paid. And for half the participants, those predictions were correct. Still, it's obviously just chance, right?

Apparently not so obvious. Those who got a correct "prediction" in round one were three times more likely to pay for one in round two than those who'd got an incorrect one. And by the time a subset of the group had got four correct predictions in a row, the possibility that they would buy a prediction for the fifth round had risen from 15 to 40 per cent.

In other words, just a few lucky guesses are all it takes to get people to pay for what the authors call "transparently useless advice". As they conclude:

Our experiment accurately describes how the real "false" experts typically operate in the information market, and the findings of this paper help to highlight how easy it is for an average person to form a belief in an expert when none may actually exist. 

Something worth bearing in mind next time you are looking at horse tips, stock pickers, or hedge funds, maybe.

George Bush tosses a coin. Is he an expert? Photograph: Getty Images

Alex Hern is a technology reporter for the Guardian. He was formerly staff writer at the New Statesman. You should follow Alex on Twitter.

Photo: Getty
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When Donald Trump talks, remember that Donald Trump almost always lies

Anyone getting excited about a trade deal between the United States and the United Kingdom should pay more attention to what Trump does, not what he says. 

Celebrations all round at the Times, which has bagged the first British newspaper interview with President-Elect Donald Trump.

Here are the headlines: he’s said that the EU has become a “vehicle for Germany”, that Nato is “obsolete” as it hasn’t focused on the big issue of the time (tackling Islamic terrorism), and that he expects that other countries will join the United Kingdom in leaving the European Union.

But what will trigger celebrations outside of the News Building is that Trump has this to say about a US-UK trade deal: his administration will ““work very hard to get it done quickly and done properly”. Time for champagne at Downing Street?

When reading or listening to an interview with Donald Trump, don’t forget that this is the man who has lied about, among other things, who really paid for gifts to charity on Celebrity Apprentice, being named Michigan’s Man of the Year in 2011, and making Mexico pay for a border wall between it and the United States. So take everything he promises with an ocean’s worth of salt, and instead look at what he does.   

Remember that in the same interview, the President-Elect threatened to hit BMW with sanctions over its decision to put a factory in Mexico, not the United States. More importantly, look at the people he is appointing to fill key trade posts: they are not free traders or anything like it. Anyone waiting for a Trump-backed trade deal that is “good for the UK” will wait a long time.

And as chess champion turned Putin-critic-in-chief Garry Kasparov notes on Twitter, it’s worth noting that Trump’s remarks on foreign affairs are near-identical to Putin’s. The idea that Nato’s traditional purpose is obsolete and that the focus should be on Islamic terrorism, meanwhile, will come as a shock to the Baltic states, and indeed, to the 650 British soldiers who have been sent to Estonia and Poland as part of a Nato deployment to deter Russian aggression against those countries.

All in all, I wouldn’t start declaring the new President is good news for the UK just yet.

Stephen Bush is special correspondent at the New Statesman. His daily briefing, Morning Call, provides a quick and essential guide to British politics.