A smile's worth a thousand words - or is it?

Think you're an ace at figuring out when people are genuine, when they're insincere? Decoding body languages, expressions, and gestures is one of the most natural things for human beings, but it turns out we're not always that good at it (or some people are just really good at dissimulating). The BBC UK has put together an online test to judge how good you are at discerning whether a smile is fake or genuine. Try it here.

I got 80% and of those I got wrong, it was evenly split between fake smiles I thought were genuine and vice versa. How'd you do?