The human face is capable of conveying thousands of shades of emotions - from anger to violent joy. But only 8 of them are identical for representatives of almost all cultural groups. This is stated in the latest study published in the online journal IEEE Transactions on Affective Computing.
So, to convey disgust, people use only one emotion. To express fear - three, to surprise - four, five - to express sadness and anger. And to express different forms of joy, a person uses as many as 17 forms of emotions!
“It speaks to the complex nature of happiness,” explains Ohio State University computer science professor and study author Alex Martinez. “It is the feeling of joy that brings people together, which is why evolution has made this feeling more difficult to express than disgust.”
The study found that the differences between how our faces convey happiness lie in the width of the smile, the amount of wrinkles that appear around the eyes and mouth.
The results are based on previous work by Martinez on facial expressions. This study showed that people are able to correctly identify other people's emotions 75% of the time, based solely on subtle changes in the color (due to blood flow) of a person's nose, cheeks, or chin.
I must say that thinkers have long tried to classify human emotions. Ancient Chinese texts dating back to 213 BC described seven human feelings: joy, anger, sadness, fear, love, dislike, and sympathy.
But Martinez, who in his work relies both on the physiological and psychological behavioral characteristics of a person, and on precise mathematical calculations, believed that there were much more emotions. “To think that people are capable of only eight manifestations of feelings is absurd. We are complex beings, and our perception of the world is wider than the eight emotions,” he said.
Based on computer algorithms, Martinez determined that the human face is capable of 16,384 different grimaces by grouping different muscles in different ways. The scientist assumed that he could identify several hundred emotions based on so many grimaces. But after selecting and examining 7.2 million faces and sorting them into categories, he found only 35 emotions. “We were in shock,” Martinez admits. “I thought there would be a lot more.”
Since the number of universal expressions turned out to be less than expected, he wondered whether most emotional expressions are specific or universal to people of different cultural groups. The result of the study surprised him even more. The analysis showed that there are only eight expressions that are used in most cultures (though not in all). These eight expressions convey positive and negative feelings, but not categories of emotion such as joy or anger. As a result, the scientist concluded that most of the expressions of emotions on the face are universal, but there are only a few dozen of them, and most of them are used to express joy.