Why You Should Never Trust A Person's Face, According To Research

Whether a job interview or a first date, you've probably been in a situation where you were desperate to read someone else's emotions. If you relied on visual clues to determine whether the person was satisfied or interested, according to new research, you were looking in the wrong place. 

During the annual meeting of the American Association for the Advancement of Science (AAAS) researchers revealed why we should never trust a person's face. 

"Not everyone who smiles is happy, and not everyone who is happy smiles," lead researcher Aleix Martinez, Ph.D., told mbg. 

Martinez and his team of researchers—scientists from Northeastern University, the California Institute of Technology, and the University of Wisconsin—studied more than 5 million images of facial expressions from 35 different countries. They also compared the muscle movements of the human face to the muscle movements with a person's emotions. 

When attempting to determine someone's emotion based on their face, the researchers were nearly always wrong. So how can we figure out what someone's feeling without verbal confirmation?

While we can activate our muscles to make certain facial expressions, we have no control over our blood flow. When we experience emotions, the "brain releases peptides—mostly hormones—that change the blood flow and blood composition," Martinez said in a news release. When the face is flooded with those peptides, it changes color. 

In Martinez's previous research, he found "color can successfully communicate 18 distinct emotion categories to an observer."

You might recognize these color variations—when someone is angry or embarrassed, red will flush to their cheeks. On the other hand, when someone is frightened, they might turn pale. 

If you're from the U.S., you're probably used to smiling when you make eye contact with someone. Culturally, we've been taught, it's the polite thing to do. "But in some cultures," Martinez said, "if you walked around the supermarket smiling at everyone, you might get smacked."

Recognizing that facial expressions do not define someone's true feelings can prevent us from making wrongful judgments. 

"Some claim they can detect whether someone is guilty of a crime or not, or whether a student is paying attention in class," Martinez said. Making these assumptions can alter the way we perceive a person, causing us to make unjust decisions about their abilities. 

According to Martinez, these findings can help everyone, from hiring managers to professors to criminal justice experts, make more fair and holistic evaluations of a person.