Just before this BBC podcast gets underway, here's something you may not know.

My name's Linda Davies and I Commission Podcasts for BBC Sounds.

As you'd expect, at the BBC we make podcasts of the very highest quality featuring the most knowledgeable

experts and genuinely engaging voices. What you may not know is that the BBC

makes podcasts about all kinds of things like pop stars,

poltergeist, cricket, and conspiracy theories and that's just a few examples.

If you'd like to discover something a little bit unexpected, find your next podcast over at BBC Sounds.

Hello and welcome to more or less on the BBC World Service.

We're the programme which celebrates and checks the numbers that surround us in the news and everyday life, and I'm Tim Harford.

This week I've been talking to Bobby Duffy, the managing director of Ipsos Moray's Social Research Institute,

and the author of a new book, The Perils of Perception,

Why We're Wrong About Nearly Everything.

The book reveals how little so many of us know

about the basic facts of our world.

Bob is based his book on the research his team have done in 40 countries,

and when we went into the studio, he and my disloyal producer had laid a little trap for me.

So just as we were coming in here, my producer Ruth Alexander told me that I was going to be tested.

I did not in fact expect this, so that you're going to test my misperceptions of the world so come on I'm ready I'm ready

I present more rest don't you know I can do it this is risky for you this is risky for you too This is risky for you.

Yeah, well, you lived dangerously as a radio 4 presenter.

Good. So let's pick one of the ones that Britain comes top of the wrongness list on.

Let's see if you're better than your country people. So what proportion is? of the

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