Spot the Fake Smile

"Most people are surprisingly bad at spotting fake smiles," says the BBC, based on University of California psychological research. "One possible explanation for this is that it may be easier for people to get along if they don't always know what others are really feeling."

How's your grin detector? Mine's working with 75% accuracy, according to the online visual quiz. Look at 20 faces and identify the right smiles, bright eyes.

Try: Spot the Fake Smile