What Our Pupils Reveal

What Our Pupils Reveal

Last update: 21 February, 2022

They say that the eyes are the mirror of the soul, and we know with scientific certainty that the eyes are a window to the brain, the only visible part of our nervous system.

The eyes can reveal a lot about us. Through the reduction and expansion of our pupils, we can know if we are excited, disgusted, and other such sensations.

The eyes, and particularly our pupils, not only help us to see, but also indicate what is happening in our minds .

So what do our pupils tell us about our  thoughts?

Whether we’re having trouble answering (or lying)

A study has shown that the harder the brain works and has to make an effort, the more our pupils dilate. If you have to give a simple response, your pupils barely change. When a response is more difficult for you, your pupils dilate.

With this, we can see if it is difficult for someone to respond to a question and, even more interestingly, if he is lying or not. 

Whether our brain is overloaded

If you really focus on someone’s eyes while they are doing “impossible” multiplication, like 1345 x 2022, and demand a response, their pupils respond by dilating.

When people’s minds are overloaded past 125% of their capacity, their pupils dilate and they leave the problem for later or give up.

If the brain is damaged

When doctors or nurses put a blinking light in front of patients’ eyes to see if their brains are functioning correctly, a healthy brain’s pupils are equal, round, and responsive to the light. This simple checking of the pupils is called PERRL.

If the brain has suffered trauma from a harsh blow, PERRL is likely not seen.

Whether we are interested in what we are hearing 

The size of our pupils can also indicate whether or not we are interested in the conversation.

In one study, they made students listen to 3 summaries of three books: one erotic, another about a bloody mutilation, while the third was about a neutral topic.

At first, the pupils were dilated for all three topics, but later, the pupils remained dilated for the entire summary of the books on eroticism and mutilation, while they contracted again for the neutral one.

The pupils, like our minds, are initially susceptible to everything new. However, the pupils will remain dilated if the novelty does not wear off.

Whether we’re aroused

When we are sexually aroused, our eyes take part fully in the passion. The pupils of men and women dilate.

However, not everyone agrees about the degree of this connection. Some psychologists argue that pupil dilation is merely a reaction to the visual stimulus of nudity, rather than a reaction to the emotion of arousal.

Whether we are disgusted

In the same way that the pupils grow when we are interested in something, they shrink when we are disgusted.

Hess, using pupillometry in 1972, tested the reactions that images of injured children caused in the pupils of some people. He noted that upon first seeing the images, the pupils grew out of shock and later shrank as if wanting to avoid the unsettling figures.

Our political inclination

If you’re willing to carry around photos of politicians, you might be able to gain insight into the the political inclination of those you come in contact with by observing the dilation of their pupils.

Barlow (1969) did a curious experiment, selecting Americans sympathizing with each side. Upon seeing liberal politicians, their supporters’ pupils dilated, while seeing conservative politicians made them contract. This behavior, of course, was also seen in conservative supporters: seeing liberals, their pupils contracted, and seeing conservative representatives, their pupils dilated.

Whether we are experiencing pain 

Some slightly sadistic researchers like Chapman (1999) introduced small electric shocks to the hands of some poor volunteers and measured how much their pupils dilated. Under the most intense pain, their eyes dilated by approximately 0.2 millimeters.

Whether we’re under the influence of drugs or alchohol

Some drugs like alcohol and opiates provoke pupil contraction. Other drugs like amphetamines, cocaine, LSD, and mescaline cause the pupils to dilate.

Observe the pupils and you can discover information about everyone. The iris also reveals other signs.

Look at the eyes!


This text is provided for informational purposes only and does not replace consultation with a professional. If in doubt, consult your specialist.