Following in the footsteps of Darwin, who first established facial expressions as a universal language, a recent study revealed that the wrinkles around a person's eyes can portray how sincere or intense their emotions are.
These new findings take us a step closer toward understanding facial expressions and how they relate to our understanding of emotion.
The research was conducted at the University of Western Ontario in London, Canada, in collaboration with investigators from the University of Miami in Coral Gables, FL.
The results were published recently in the journal Emotion.
Daniel Messinger, Ph.D. — a professor of psychology at the University of Miami — says, "Since Darwin, scientists have wondered if there is a language of facial expression. This research suggests one key to this language is constriction of the eyes."
Using the Duchenne smile marker
The Duchenne smile is essentially a "genuine" smile; it is named after the French physician Duchenne de Boulogne, who proved that smiles from "true happiness" involve not only the muscles of the mouth, but also the eyes.
The new study focused on the Duchenne marker, which is a measurement of eye wrinkles appearing in facial expressions. Using a method known as visual rivalry, study participants were shown photographs of facial expressions with and without the Duchenne marker.
Visual rivalry tests are designed to find which of two pictures the brain pays most attention to. They found that expressions including Duchenne markers were perceived as more important to our subconscious minds.
When the study group was asked to rate the scale of expressions, Duchenne expressions were also rated as more intense and sincere than their counterparts.
"The expressions involving the Duchenne marker were always dominant. So if the emotion is more intense, your brain actually prefers to bring it into perceptual awareness for a longer time."
Lead investigator Dr. Julio Martinez-Trujillo
Facial expression analysis
Truly understanding the relationship between facial expressions and emotions could lead to groundbreaking real-world applications. In fact, discoveries in the field have already led to initiatives and programs that help to teach people how to read emotion.
Dr. Martinez-Trujillo is interested in whether the results of the current study would be the same for those on the autistic spectrum. He explains:
"When you have social interactions you need to perceive whether a person is sincere or not. So my interest now is, what will be the results if we do this same test with people with autism spectrum disorder. They often have trouble reading out emotions from other people, so we wonder if that might have to do with their ability to read this marker for sincerity."
Researchers have been investigating facial expressions for more than 100 years. Darwin's study in 1872 is regarded as the most significant contribution, being the first to suggest that facial expressions are universal.
He deduced that emotions and their expressions were biologically innate and evolutionarily adaptive, and that similarities can be seen in closely related species.
Arguably the most significant smile-focused study was conducted in 1989 by psychologist Robert Zajonc, who asked subjects to repeat vowel sounds that forced their faces into smiles or pouty expressions. Zajonc's study proved that even a fake smile can induce a feeling of happiness.
This new study is an interesting development in the field of facial expression analysis.
A universal language for reading emotions
Ultimately, this study proved that eye wrinkles represent and communicate sincere emotions. First study author Nour Malek, Ph.D., says, "These findings provide evidence of a potential universal language for reading emotions."
"In other words," she continues, "a given facial action may have a single role across multiple facial expressions — especially if that facial action shapes your social interactions."
"For example," Malek concludes, "knowing if a stranger's smile is genuine and whether that person can be trusted, warns you whether you should evade or not."