Eyes are the window to a person’s soul, the old saying goes. And science is backing it up. The whites of your eyes (known as the sclera), your pupils, and the muscles of your face and eyelids all perform together to communicate with others what you are thinking and feeling. In fact, scientists can determine some of your brain activity simply from your pupils.
There are obvious social cues that come from our eyes, such as rolling them or averting them intentionally. The fact that our sclera – the whites of our eyes – are highly visible make this type of nonverbal communication possible, unlike most animals whose sclera is not visible or barely visible. While we can consciously send cues out like those mentioned, most of our social cues and expression of feelings and thoughts through our eyes are unconscious.
When we are uncomfortable or disagree with someone, we often shift our gaze down and away. When we are lying, we often shift our eyes up and to the right, while if we are telling the truth, our gaze shifts up and to the left. However, many people also glance around while speaking, so these shifts may be due to simply that. But these movements are known to be reliable enough that the FBI can use them in reading body language.
Our rate of blinking or dilation of the pupils can indicate emotion. Higher rates of blinking can be a sign of stress (unconsciously) or a sign of flirtation (consciously or unconsciously). Pupil dilation also says many things. When we focus on something our pupils dilate. For example, researchers found that when people focus on multiplication problems, their pupils dilated slightly. On harder multiplication problems, their pupils dilated wider and stayed dilated until the person either solved the problem or gave up, at which point the pupil immediately constricted. When decisions are made, the pupil dilates slightly and then constricts following the decision. Finally, our pupils dilate due to adrenaline; if we are surprised by something or fearful of something our pupils will dilate.
Because of the many ways that our eyes show thought and emotion, we are attuned subconsciously to “normal” patterns in eye movement and pupil dilation. That is why, when someone’s pupils are dilated abnormally, we sense that something is off – either the person has had something artificially dilate it (such as drugs) or something is wrong with their eyes. If you find that your pupils are dilated and you do not know why, it is a good idea to have your eyes examined to find out the cause. In a following blog article, we will examine abnormal causes of pupil dilation.