How could a smile be so deceiving? Well apparently it can, according to this new video from In59Seconds.
The video, which shows how to sniff out a fake smile tests your ability to spot a facial expression that isn't so real - and we don't mean to brag, but we got full marks on the test.
Dr Richard Wiseman, from University of Hertfordshire, looks at the sure signs behind a 'real' smile, including the formation of those cute little eye crinkles that appear when you're beaming from ear to ear.
So, if you're feeling like your Sherlock skills are on form then watch the video, spot the signs of a fake smiler and let us know how you did!
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