It is said that the eyes are the “mirror of the soul”, that when we look someone in the eye, we are able to perceive its essence. And the truth is that this statement is not entirely wrong, because the eyes offer a lot of information concerning the emotional state of a person.
When people are sad or worried frown the forehead, this makes that their eyes look smaller. But when they are happy we say that their eyes shine, because this emotion makes that the eyebrows raise, so that the eyes appear bigger and brighter.
In addition, we can distinguish between a genuine smile, also known as “Duchenne smile” and a fake one, just by looking in the eyes of the person. In fact, the mouth movements are easy to imitate, we do it continuously for courtesy, but the eyes don’t lie: when we are really happy not only we smile but also wrinkle the corners of the eyes, forming what are called “crow’s feet”. However, when people feign a smile, they usually forget the eyes, which remain expressionless.
What the pupils and eye movements tell
If the eye is the mirror, the pupil is literally an opening in the eye. The pupil functions as the shutter of a camera, expanding and contracting to adjust the amount of light that enters the eye. Therefore, our pupils contract with light and expand with the darkness.
But the pupils do not simply respond to light, also express our emotions and intentions. In fact, the pupils dilate even when we are excited, because our body activates a warning network involving the autonomic nervous system by preparing to respond when we are faced with a threat or an opportunity. For this reason it is considered that the dilation of the pupil is a true signal of sexual interest.
However, the pupils dilate even in response to a stimulus that draws our attention. When we are exploring the environment, for example, the pupils dilate to capture as much visual information as possible. Therefore, the dilation of the pupils is considered a signal of great interest even in conversation.
But the pupils are not the only ones that offer information. Even eye movements are important. In fact, a study conducted at Arizona State University found that curious people move continuously their eyes. These psychologists evaluated the level of curiosity of the participants, such as the desire to acquire new knowledge and new experiences. Later they asked them to see a series of images, while their eye movements were monitored. So they saw that the most curious people were even those who constantly moved the eyes looking for information.
Also closing the lids we may reveal information about us. In this regard, some psychologists from the University of Portsmouth have discovered that the way we blink the eyelids can indicate whether we are lying or not. The researchers asked a group of people to tell a false story and to others to remember an event that really happened in their lives. Analyzing their behavior they saw that when a person is lying does not close his eyes continually.
It is interesting, because normally opening and closing the eyes several times is considered a sign of nervousness, and keeping our eyes open for a long time means we’re doing a cognitive effort. In fact, when we lie our brain can suffer a cognitive overload, which prevents it from maintaining the same level of control over various functions that normally occur automatically.
So, now you know that the eyes are the mirror of the soul, or at least a small window that shows a part of us and discover a part of the other. The English writer Gilbert Keith Chesterton was right when he said that “there is a path between the eyes and the heart that does not go through the intellect”.
Mathôt, S. & Van der Stigchel, S. (2015) New light on the mind’s eye: the pupillary light response as active vision. Current Directions in Psychological Science; 24: 374-378.
Risko, E. F. et. Al. (2012) Curious eyes: Individual differences in personality predict eye movement behavior in scene-viewing. Cognition; 122(1): 86–90.
Mann, S.; Vrij, A. & Bull, R. (2002) Suspects, Lies, and Videotape: An Analysis of Authentic High-Stake Liars. Law and Human Behavior; 26(3): 365-376.