The colour of happiness: We really are social chameleons
Our changing face colours signal how we’re feeling
We argue until we’re “blue in the face”. If we’re “green around the gills” we’re disgusted by something. “Blushing brides” are happy.
Now research has shown that idioms using facial colour to characterise emotions contain more than a grain of truth. In fact, scientists say the colour of our faces gives away our feelings even if we don’t move a muscle.
This holds true regardless of gender, ethnicity or overall skin tone, said Aleix Martinez, a cognitive scientist and professor of electrical and computer engineering at The Ohio State University in the US.
His team are patenting the computer algorithms they created and hope they will enable future forms of artificial intelligence to recognise and emulate human emotions. They have also formed a spin-off company, Online Emotion, to commercialise the research.The study, published in the Proceedings of the National Academy of Sciences, found that people are able to correctly identify other people’s feelings up to 75% of the time based solely on subtle shifts in blood-flow colour around the nose, eyebrows, cheeks and chin.
Using the knowledge, the researchers created algorithms that achieved a success rate of up to 90% when asked to identify the emotions underlying neutral expressions.
“We identified patterns of facial colouring that are unique to every emotion we studied,” said Martinez.“We believe these colour patterns are due to subtle changes in blood flow or blood composition triggered by the central nervous system. Not only do we perceive these changes in facial colour, but we use them to correctly identify how other people are feeling, whether we do it consciously or not.”
The researchers took hundreds of pictures of facial expressions and separated them into red-green and blue-yellow channels. Computer analysis revealed that emotions formed distinct colour patterns.To test whether colours alone could convey emotions, they superimposed the patterns on pictures of faces with neutral expressions. They showed the neutral faces to 20 study participants and asked them to guess how the person in the picture was feeling, choosing from a list of 18 emotions.
About 70% of the time, participants thought a neutral face that had been manipulated to look happy actually conveyed happiness. They thought faces made to look sad were actually sad about 75% of the time, and neutral faces retouched to look angry were actually angry about 65% of the time.Next, researchers showed participants facial expressions of happiness, sadness and other emotions. This time, however, they mixed up the colours on some of the images. For example, they sometimes took a happy face and put angry colours on it. Participants said something about the images looked “off”, even if they weren’t sure what was wrong.“[They] could clearly identify which images had the congruent versus the incongruent colours,” said Martinez.
Using algorithms developed by the researchers, the computer found happiness the easiest emotion to recognise by colour alone, with 90% accuracy. Anger was detectable by colour 80% of the time, sadness 75% and fear 70%.
“There’s a little bit of every colour everywhere,” Martinez said. Touches of red, green, blue and yellow characterise every emotion — just in slightly different amounts or locations around the face.
Disgust, for instance, creates a blue-yellow cast around the lips, but with a red-green cast around the nose and forehead.