Researchers have shown that our brains are pre-wired to perceive wrinkles around the eyes as more intense and sincere emotions. This eye wrinkle feature, called the Duchenne mark, appears in multiple facial expressions, such as smiling, expressions associated with pain, and—as found by these researchers—expressions of sadness.
Using a method called visual rivalry, the researchers showed participants pictures of expressions with and without the Duchenne marker to study which of the expressions our brains consider more important. When different images are shown in each eye, the brain alternates between these two images, but will more often bring the image perceived as more relevant into perceptual awareness.
The study's lead researcher says visual rivalry is like a window into the unconscious, showing what our brains involuntarily see as more relevant or important. "The expressions with the Duchenne marker were always dominant, so when the emotion is more intense, your brain actually prefers to put it into perceptual awareness for a longer period of time," said the researcher.
The researchers also asked participants to rate the expressions on a scale for intensity and sincerity, and found that people systematically ranked the Duchenne smile and Duchenne sad expressions as more sincere and intense than the non-Duchenne expressions.
