How to spot a fake smile from the real thing

Both real and fake smiles depend on cranial nerve VII, also known as the facial nerve - (Getty)

You’ve probably heard the claim that it takes more muscles to frown than to smile. It’s usually framed as a feel-good reason to turn your frown upside down – less effort, more joy. But anatomically, the numbers don’t quite add up.

We’ve all seen it – the smile that doesn’t quite reach the eyes. From awkward family photos to strained workplace pleasantries, our brains often detect that something is off long before we consciously realise why.