Dr. Aleix Martinez, professor of electrical engineering, has been working with facial expression research for the past 20 years. Courtesy of OSU

From joy to sadness, there are thousands of ways we express emotion, but a new study found that many emotions are understood through fewer facial expressions than previously thought.

Recently published in the Journal of Institute of Electrical and Electronics Engineers Transactions on Affective Computing, the study conducted by Aleix Martinez, professor of electrical and computer engineering at Ohio State, found that about half of those expressions turned out to be some variation of happiness.

“We identified 17 different facial expressions of positive emotions,“ Martinez said. “The amount of facial expressions that convey happiness is astounding.”

Martinez, who has been working with facial research for the past 20 years, said this study was different because of the powerful computers with which he had access, as well as the amount of images they gathered compared to his previous research. After studying millions of faces from around the world, they only found 35.

“We were expecting to identify a few dozen [facial expressions], maybe even a hundred,”  Martinez said.

Along with Ramprakash Srinivasan, journal co-author and doctoral student in the college of engineering, the team worked to group together and define words to describe those 35 different feelings. Their research found that there were almost no facial expressions that were exclusive to a single culture.

“Further research will need to study which of these effects are cross-culture and which [are] cultural-specific in the production and perception of emotion in the wild,” Srinivasan said in the paper’s conclusion.

The number of universal expressions that exist cross-culturally has plagued researchers and philosophers since the days of ancient Greece according to the paper. Even scientist Charles Darwin hypothesized that there are only six universal emotions that humans are capable of displaying.

Alternately to happiness, the feeling of disgust had only one expression. Distinct emotions like pain or pleasure are understood universally, such as a frown is considered to be a bad sign all over the world.

The study also found almost no facial difference between reacting to a funny joke or experiencing road rage.

According to the group’s research, people don’t need to be able to understand another’s culture to communicate effectively through universal nonverbal cues, which is a different factor for humans.

“Non-verbal communication signals are extremely important, “ Srinivasan said. “It’s a sort of glue so to speak in our society to interact with each other.”