Here’s something to smile about — 20 other facial expressions

Happy, sad, and angry do not even begin to cover the range of emotions we express in our faces, a study has found.

Using new computer software, scientists mapped no less than 21 emotional states, including apparently contradictory examples such as “happily disgusted” and “sadly angry”.

The research more than triples the number of known emotional facial expressions.

Dr Aleix Martinez, from Ohio State University, said: “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.

“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.”

In future, the computer model could aid diagnosis and treatment of conditions such as autism and post-traumatic stress disorder, the researchers said.

Since the time of Aristotle, scholars have tried to understand how and why our faces betray our feelings. Today, cognitive scientists try to link facial expressions to emotions in order to track the genetic and chemical pathways that govern emotion in the brain.

Until now they have focused on six basic emotions: Happy, sad, fearful, angry, surprised, and disgusted.

Restricting emotions to just six categories is like painting only using primary colours, said Martinez. The new study, published in the journal Proceedings of the National Academy of Sciences, has tripled the colour palette available to researchers.

The team photographed 230 mostly student volunteers — 100 male, 130 female — making faces in response to verbal cues designed to trigger emotional states.