In a new study, researchers were able to get a computer to recognize 21 new complex facial expressions, tripling how many already exist for cognitive analysis.

Researchers at Ohio State University (OSU) have even added contradictory expressions like "happily disgusted" or "sadly angry." According to a press release, their objective was simply to expand the field of expressions used in facial analysis studies.

The study is published in the journal Proceedings of the National Academy of Sciences.

"We've gone beyond facial expressions for simple emotions like 'happy' or 'sad.' We found a strong consistency in how people move their facial muscles to express 21 categories of emotions," Aleix Martinez, a cognitive scientist and associate professor of electrical and computer engineering at OSU, said in the release. "That is simply stunning. That tells us that these 21 emotions are expressed in the same way by nearly everyone, at least in our culture."

Since the research involves mapping a person's brain, the study might also be of use in treating and diagnosing mental conditions like autism and posttraumatic stress disorder (PTSD). Even the earliest philosophers have tried to figure out why people can sometimes convey an emotion they are not experiencing with a false facial expression. This study has aimed to track the chemical reaction that occurs in the brain when we feel an emotion.

"In cognitive science, we have this basic assumption that the brain is a computer. So we want to find the algorithm implemented in our brain that allows us to recognize emotion in facial expressions," said Martinez. "In the past, when we were trying to decode that algorithm using only those six basic emotion categories, we were having tremendous difficulty. Hopefully with the addition of more categories, we'll now have a better way of decoding and analyzing the algorithm in the brain."

Researchers in this field have previously only worked with six basic facial expressions: happy, sad, angry, surprised, disgusted and fearful. The researchers photographed about 130 females and 100 males, asking them to react with just a facial expression to various scenarios.

Martinez said the study was only meant to aid cognition research, but he can envision it being used for much more.

"For example, if in PTSD people are more attuned to anger and fear, can we speculate that they will be tuned to all the compound emotions that involve anger or fear, and perhaps be super-tuned to something like 'angrily fearful'? What are the pathways, the chemicals in the brain that activate those emotions? We can make more hypotheses now, and test them," he said. "Then eventually we can begin to understand these disorders much better, and develop therapies or medicine to alleviate them."