Research on smiling started as far back as the mid-1800’s. A French doctor named Duchenne used electrical currents with research subjects. He would stimulate certain facial muscles and then take pictures of the expressions that people made. This was painful and many of the pictures look like the people are in pain.
Real or fake? — Duchenne identified two different types of smiles. Some smiles involve contraction of both the zygomatic major muscle (which raises the corners of the mouth) and the orbicularis oculi muscle (which raises the cheeks and makes your eyes crinkle). Smiles that contract both of these muscle groups are called “Duchenne” smiles. In a “non-Duchenne” smile only the zygomatic major muscle contracts, in other words your mouth turns up, but your eyes don’t crinkle.
Can you fake a smile? — After Duchenne, several researchers used these ideas to research smiling. For years it was believed that the Duchenne smiles were the ones that were seen as genuine, that it was not possible to “fake” a smile, because up to 80% of people can’t consciously control the muscles around the eyes that make them crinkle. Why all the interest in whether a smile is real or fake? Because people are quicker to trust and like other people who are showing what is believed to be genuine emotions rather than fake or contrived ones.
Questioning the 80% figure — Krumhuber and Manstead (2009) decided to research whether it was true that most people couldn’t create a fake smile that looks real. Their results were fairly astounding. They found the opposite of what was previously believed. In their research 83% of the people could produce fake smiles that other people thought were real when they looked at photos of the people pretending to smile.
Videos tell more of the story — They also decided to test videos rather than just photos. What they found was that it was harder to fake a smile in a video, but not because of the crinkly eyes. People could tell real from fake by paying attention to other factors, such as how long they held the smile, and whether they saw other emotions besides happiness, for example, a flicker of impatience. The video made it easier to detect a fake smile because it lasted longer and was dynamic, instead of just an instant’s snapshot.
What do you think? Can you tell a fake smile from a real one?
If you want to read the research:
Krumhuber, Eva G., & Manstead, A. (2009). Can Duchenne smiles be feigned? New evidence on felt and false smiles. Emotion, 9(6), 807-820.