BoingBoing reports on a BBC site, based on research by Psychologist Paul Ekman, where you can test your ability to detect fake smiles. It turns out, most people are “surprisingly bad” at differentiating genuine from fake smiles. Take the test or read more on how to spot fake smiles (after the jump).

According to the study summary, most people are very bad at detecting fake vs. genuine smiles, though there are tell-tale signs:

Fake smiles can be performed at will, because the brain signals that create them come from the conscious part of the brain and prompt the zygomaticus major muscles in the cheeks to contract. These are the muscles that pull the corners of the mouth outwards.

Genuine smiles, on the other hand, are generated by the unconscious brain, so are automatic. When people feel pleasure, signals pass through the part of the brain that processes emotion. As well as making the mouth muscles move, the muscles that raise the cheeks – the orbicularis oculi and the pars orbitalis – also contract, making the eyes crease up, and the eyebrows dip slightly.

Lines around the eyes do sometimes appear in intense fake smiles, and the cheeks may bunch up, making it look as if the eyes are contracting and the smile is genuine. But there are a few key signs that distinguish these smiles from real ones. For example, when a smile is genuine, the eye cover fold – the fleshy part of the eye between the eyebrow and the eyelid – moves downwards and the end of the eyebrows dip slightly.

I guessed about 50% of the smiles correctly, which is exactly chance.  Oddly, I found myself suspecting that they were all faking.  I wonder what that says about me!

Lisa Wade, PhD is an Associate Professor at Tulane University. She is the author of American Hookup, a book about college sexual culture; a textbook about gender; and a forthcoming introductory text: Terrible Magnificent Sociology. You can follow her on Twitter and Instagram.