Turn of the head to the left makes a happy face look happier, while a look to the right writes sadness all over your face

A slight turn of the head to the left makes a happy face look happier, while a look to the right writes sadness all over your face, a University of Melbourne, Australia , study has found.

Researchers from the Departments of Psychology and Dental Science, collaborating with the National Institute of Police Science in Japan, have found that sad faces look even sadder when the head is turned to the right - so that more of the left side of the face can be seen.

In contrast, happy faces look happier when the face is turned a little to the left.

Lead researcher, Associate Professor Mike Nicholls, says, “We found that comparatively minor turns of the head can have a dramatic effect on the way people perceive our emotions.”

When the researchers took the images of the left and right turned faces and reversed them in a mirror, they found a moderation of the head-turning effect.

Associate Professor Nicholls says, “The fact that the mirror reversal had only a moderating effect and did not reverse the bias suggests that the perceptual biases were primarily tied to subtle changes in the models’ face.”

“The fact that an effect of mirror-reversal was found, however, does suggest that we look to the left side of a person's face when they are sad and to the right when they are happy.”

A 3-D movement analysis revealed that the strong bias towards the perception of sadness and happiness in the left and right sides of the face was not matched by different levels of movement in the facial muscles.

The researchers found that there was more movement in the left side of the face for both happy and sad emotions, which was more pronounced for negative expressions, and the movement analysis could not account for the bias in people’s perception of the images.

Associate Professor Nicholls says, “It appears that people are able to pick up subtle changes associated with the expression of emotions that our present movement analysis is unable to detect.”

Recently published in the Proceedings of the Royal Society of London B, the study illustrates the sensitivity with which people are able to detect tiny changes in the faces of others and that comparatively minor turns of the head can have a dramatic effect on the perception of emotions.

“Turning the head to the left or the right has the potential to be an important component of non-verbal, almost non-conscious, communication between people. We may not be aware that we use it as a tool of communication, nor that it affects the way we perceive or interpret the emotions of others.”

“Given the universality of human expression, where a smile means the same thing all over the world, it is tempting to suggest that head turning is also part of an instinctive means of non-verbal communication,” he says.