Your Brain Knows the Difference Between Phony Smiles and Real Ones

By Breanna Draxler | June 12, 2013 1:40 pm

AFRICA, KENYA - NOV 8: Portrait of African children from the Masai Mara tribal village, near the Masai Mara National Park Reserve on November 8, 2008 in Kenya, Africa. Smiles on their faces.

Smiling comes in two distinct forms: genuine and polite. The genuine kind are those that result from a friend showing you a hilarious new grumpy cat meme. These smiles are spontaneous and indicative of pleasure. Polite smiles, on the other hand, are the ones reserved for the awkward encounters with your coworker at the coffee machine. You don’t want to be rude, but you’re not actually enjoying the exchange. You just feel like you have to go through the motions.

Whether or not a smile is genuine, it is generally a reciprocal social action. When a person smiles at you, you usually smile back. And more often than not, you respond with the same kind of smile you perceive. In a previous study, researchers found this smile-matching to be the case over 90 percent of the time.

Socially, the smiles have different meanings: a genuine smile is a social reward, whereas the polite version is a social obligation. Since people learn to anticipate rewards, researchers wanted to know if people anticipate rewarding smiles, too.

Researchers set up two different experiments to find out. The first one analyzed natural conversations. Two strangers were asked to chat for five minutes while the get-to-know-you conversation was videotaped. Researchers then counted how many times the 96 participants exchanged smiles in the videos, whether they were genuine or polite, and how long it took for one person’s facial expression to trigger the other’s.

The resulting analysis showed that 21 percent of genuine smiles were reciprocated before the 200-millisecond mark (the minimum amount of time required to process and respond to a stimulus with a complex, voluntary response) compared to only 7 percent of polite ones. This indicated that genuine smiles were actually being predicted by recipients, while polite ones were only responded to after the fact.

To figure out why this is, the researchers conducted a second study. Thirty-five participants learned to play a button-pressing game in which correct answers were rewarded with a smiling animated face. Two of the faces gave fake smiles, and two gave real smiles. While playing this game, participants were hooked up to an electromyography machine which monitored the neurons responsible for contracting smile muscles.

This test showed that participants’ facial muscles started contracting even before the genuine smile was given—confirming that we’re subconsciously prepped for the real thing, according to the findings published in Psychological Science. Keep that in mind next time you try to fool your angry landlord with phony politesse.


Image courtesy of Anna Omelchenko/Shutterstock

CATEGORIZED UNDER: Mind & Brain, top posts
MORE ABOUT: emotions, psychology
  • Michael Harrison

    According to the phys psych text that was used for the course I took, there was also an issue of some of the muscles used to smile being involuntary.

    • Israel Navas Duran

      The only involuntary muscles are the smooth muscle (present in different organs and structures like the iris) and the heart muscle. What they may mean are involuntary muscle contractions, but those same muscles can be also contracted voluntarily.

  • rameshraghuvanshi

    Our mirror neutrons are very sharped and extraordinary active so they easily understand phony smiles and real one. you face language expressed that easily. Phony smiles artificially expressed on face on the contrary real smiles on face spread on your entire body ,body language show that prominent way

  • chatpaltam o

    we also know when people are pretending to be intrested in us.

  • Joree Felker

    I am using this for a paper for a safety class, Great for sincerity in safety, uh?


Discover's Newsletter

Sign up to get the latest science news delivered weekly right to your inbox!


Briefing you on the must-know news and trending topics in science and technology today.

See More

Collapse bottom bar