Western University researchers uncover secret to judging sincerity

You're probably familiar with the old adage "the eyes are the window to the soul." It turns out this is true, at least according to new research out of Western University.

These new findings could also alter what we know about people living with autism

Dr. Julio Martinez-Trujillo said his Duchenne marker research was inspired by his daughter, who has autism. (Photo provided by Crystal Mackay)

You're probably familiar with the old adage that eyes are the window to the soul.

Well, it turns out this is true, according to new research out of Western University.

A research team, including principal investigator Dr. Julio Martinez-Trujillo from the Schulich School of Medicine and Dentistry, said the team has figured out how people judge the level of other people's sincerity. 

Martinez-Trujillo said he found inspiration for the study in a particularly personal place. 

"I have a daughter born with autism … many people with autism don't perceive emotions very well … so I got interested in the things that make us perceive emotions or their intensity," he said.

Conducting the research

Martinez-Trujillo and his team used a technique called visual rivalry to show that the human brain may be pre-wired to perceive people with wrinkles around their eyes to be more sincere. These wrinkles, also known as the Duchenne marker, are said to occur over a wide variety of facial expressions — including joy, sadness and pain. 

Martinez-Trujillo said they appear thanks to a muscle in the face that raises the cheeks and constricts the eyes slightly so that wrinkles appear around them. 

The technique works by showing a different image to each eye at the same time through a pair of special binoculars. In one eye, each of the 30 participants involved saw the face of someone with wrinkles around their eyes, and in the other they saw that same person but without wrinkles, said Martinez-Trujillo.

Dr. Julio Martinez-Trujillo with and without a Duchenne marker. His research shows that the Duchenne marker, also known as wrinkles around the eye, make someone appear more sincere. (Photo provided by Crystal Mackay )

Researchers then measured how long the participant's awareness focused on each of the two images.

"The things that are most important to us, our brain tries to keep it for a longer time," said Martinez-Trujillo. "So if the things you show to the right eye are more relevant to you … for whatever reason, the brain will keep it longer before alternating to the left eye."

Participants were asked to press the button that corresponds to the expression that lingered in their minds, and the results were consistent.

"The image with the wrinkles was the winner all the time," he said

So, what does this mean?

Martinez-Trujillo said he believes the results of the study are important for science and culture.

The study has shown one single facial reaction occurs with multiple different emotions and provides people with a universal way to read them. In the cultural realm, people can take what they now know about this marker and learn to use it to their advantage.

"It's pretty hard to do, but if you are an actor or a politician, you can try again and again and again and you will appear more sincere," said Martinez-Trujillo. "You're probably going to go to the mirror and see if you wrinkle your eyes when you smile because you want to appear sincere in a job interview."

As for alternative explanations? Martinez-Trujillo said he doesn't believe there are any, as the research team's conclusions were partially based on background studies that date back to the 1800s. 

"I think our contribution has been that we've made these measurements that are independent from the subject's subjective report," said Martinez-Trujillo.

Next, his team will take the preliminary research and apply it to people with on the autism spectrum.