To see if you can spot a genuine smile from a fake smirk, click on the link marked 'gallery' in the blue box below. Each subject has been photographed twice - posing with a real grin and a false ...

Even more intriguingly, we learn the false-real smile difference when we're super tiny: at just 10 months old, an infant will give a false smile to a stranger, but offer up a sincere, eye-crinkly ...

He paid tribute to her, and she cracked a genuine smile then, but there is a distance ... but it feels like a false greeting.