You really are off colour if you feel blue

WHETHER it is arguing until “blue in the face” or feeling “green with envy” the English language is well-stocked with idioms linking colour to emotion.

Now for the first time, scientists have shown that people actually do change hue depending on their feelings.

Subtle alterations to skin tone and complexion around the nose, eyebrows, cheeks or chin, are picked up subconsciously by observers, making it hard to hide emotions. A sad person putting on a brave face will still flush the colour of his or her unhappiness.

Dr Aleix Martinez, a cognitive scientist at The Ohio State University, said: “We identified patterns of facial colouring that are unique to every emotion we studied. We believe these colour patterns are due to subtle changes in blood flow or blood composition triggered by the central nervous system.”

For the study, the researchers took hundreds of pictures of facial expressions and separated the images into different colour channels that correspond to how human eyes see colour – either in a red/green channel or blue/yellow.

Computer analysis of the images found that emotions such as “happy”, “sad”, “anger” or “disgust” all formed unique colour patterns.

“Disgust”, created a blue-yellow cast around the lips, but with a red-green cast around the nose and forehead. “Happiness” was seen as red at the checks and temples and a little blue around the chin, but the same face with a slightly redder forehead and slightly less blue chin registered as “surprised”.

Volunteers were able to spot an emotion up to 75 per cent of the time. The effect remained regardless of gender, ethnicity or overall skin tone. The study was published in the Proceedings of the National Academy of Sciences.