Easier to fake a smile than originally thought

For years psychologists believed that a real smile was signaled by upturned lips and crinkly eyes. This genuine smile is named after the French physician Duchenne, who passed electrical currents through live subjects and took photos of their weirdly contorted faces.

It was believed that fewer than 20% could fake a smile that would trick others because we don't have voluntary control over the muscles around our eyes which signal the Duchenne smile.

But now it seems that exactly the opposite is true. Writing in a recent issue of the journal Emotion, Krumhuber and Manstead found that 83% of the people in their study produce fake smiles that others mistook for the real thing in photographs.

The researchers also explored how people perceived genuine and fake smiles when they saw videos rather than just static pictures. Then it emerged that fake smiles were easier to spot, but the supposedly crucial crinkling around the eyes didn't help much. Instead, telling a real from fake smile relied more on dynamic processes such as how long people hold it, the symmetry of the expression and whether conflicting emotions are communicated by other facial areas.

So the Duchenne smile has taken a bit of bashing in this research, which suggests that most people can fake crinkly eyes. Not only that but the crinkly eyes aren't as crucial for us in judging the sincerity of a smile as other factors. Rather than just the crinkly eyes, it's the whole movement of the face which tells a tale either of deception or of genuine, felt emotion.

Stay tuned for more on facial symmetry.....