In A Nutshell
While it might seem as though people are capable of a wide range of facial expressions, researchers from the University of Glasgow have found that we only really have four: happiness, sadness, fear/surprise, and disgust/anger. They found that when looking at time-lapse videos of facial expressions, fear and surprise started exactly the same. So did disgust and anger, leading to the conclusion that there are only four basic expressions, and the muscles in the face go on to differentiate between expressions after they’ve formed the basics.
The Whole Bushel
When it comes to facial expressions, we like to think that humans have the market cornered. After all, if you ask anyone who’s not an animal person what their neighbor’s cat or dog is thinking just based on the expression on their face, and you’re bound to get an answer reflecting the rather narrow-minded idea that they’re not thinking at all.
While animal facial expressions might take time for an observant person to get used to, we usually like to think that we’re pretty good at reading the expressions of other people.
For a long time, we’ve tried to figure out how many facial expressions humans are capable of. If you start to name some, you’ll probably come up with ones like happiness, sadness, fear, surprise, anger, confusion, disgust, and uncertainty. According to psychology professor and FBI/CIA consultant Dr. Paul Ekman, only six of those are distinct expressions: anger, fear, surprise, happiness, contempt, and disgust.
Six doesn’t seem like very many. But the University of Glasgow has challenged his long-held theory with the idea that we’re only actually capable of four facial expressions. They suggest that disgust and anger should be counted as one, as should fear and surprise.
It’s all based on a time-lapse examination of how our facial expressions evolve. They don’t happen all at once, after all, and when researchers looked at how, when, and which facial muscles were activated for each different expression, they found that disgust and anger started out the same way.
They both started with one key element—a wrinkled nose—that then evolved to differentiate one from the other.
It was the same with fear and surprise, that both started with widening of the eyes.
It all happens in a split second, but the researchers also point out that a split second is sometimes the difference between life and death. It’s crucial that we can recognize anger as quickly as possible. (Same thing with fear.)
We’ve long relied on our reflexes to keep us alive, and at the core, that’s what facial expressions are all about giving us: a split second longer.
Another study by Ohio State University researchers thought six was too small a number. They wanted to find out how the different types of emotion—like the different kinds of happiness—are written on our faces. They wanted to know if, for instance, a happy surprise used the same muscles as both happiness and surprise on their own, or if it was a unique combination of muscle movements that allows us to convey these particular emotions.
When they mapped more then 5,000 different expressions from 230 volunteers, they were looking at the action units of Ekman’s Facial Action Coding System, which the University of Glasgow study also looked at. They found that there were 21 different expressions that we were capable of making, most of which were a combination of elements from the most basic expressions.
Given that some of the elements of these expressions can last only milliseconds, knowing what to look for can give someone a huge advantage when it comes to diagnosing mental health issues, telling whether someone’s lying, and more.
Picking up on those keys means being able to tell a fake smile from a real one. Does the surprise on someone’s face indicate true happiness, or is the person just pretending to be happy?
Show Me The Proof
University of Glasgow: Written all over your face: humans express four basic emotions rather than six, says new study
NY Times: A Conversation With Paul Ekman
Time: Human Faces Can Express at Least 21 Distinct Emotions