Washington: While our faces can convey a multitude of emotions–from anger to sadness to riotous joy, only 35 expressions can actually convey these emotions across cultures.
Disgust, for example, needs just one facial expression to get its point across throughout the world. Happiness, on the other hand, has 17–a testament to the many varied forms of cheer, delight and contentedness.
“This was delightful to discover. Because it speaks to the complex nature of happiness,” said Aleix Martinez lead author of the study.
The differences in how our faces convey happiness can be as simple as the size of our smiles or the crinkles near our eyes, the study found.
The study also found that humans use three expressions to convey fear, four to convey surprise, and five each to convey sadness and anger.
The study was published in the journal of IEEE Transactions on Affective Computing.
“Happiness acts as a social glue and needs the complexity of different facial expressions; disgust is just that: disgust,” Martinez said.
The findings were built on Martinez’s previous work on facial expressions, which found that people can correctly identify other people’s emotions about 75 per cent of the time based solely on subtle shifts in how blood flow colours a person’s nose, eyebrows, cheeks or chin.
In this study, Martinez and co-author Ramprakash Srinivasan, assembled a list of words that describe feelings–821 English words, to be exact. They then used those words to mine the internet for images of people’s faces.
Professional translators translated those words into Spanish, Mandarin Chinese, Farsi and Russian. To avoid bias, they used each word to download an equal number of images.
They plugged the words into search engines popular in 31 countries across North America, South America, Europe, Asia and Australia, and ended up with approximately 7.2 million images of facial expressions across a variety of cultures.
Psychologists have debated how to classify human emotion for centuries. An ancient Chinese text–dating back as early as 213 B.C., then modified over the years–described seven “feelings of men” as joy, anger, sadness, fear, love, disliking and liking.
Martinez, whose research interests intersect both engineering and the behaviour of the human brain, though there had to be more than just seven or eight. They took the 7.2 million images their searches yielded and sorted them into categories, looking for those that expressed emotion across cultures. Martinez figured they’d find at least a few hundred.
Martinez and Srinivasan hoped to identify the facial configurations that convey emotion across cultures. Based on computer algorithms, they found that the human face is capable of configuring itself in 16,384 unique ways, combining different muscles in different ways.
They found only 35. “We were shocked. I thought there would be way, way more,” Martinez said.
The researchers concluded that most facial expressions of emotion are universal, that there are only a few dozens of them and that a large number of them are used to express joyfulness.