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Saravanan B

The secret behind pupil dilation - A Behavioral Perspective

"Always look into the eyes"

Our eyes plays a pivotal role in our whole perceptual process. It perceives thousands of information and it is processed in the brain for decision-making, problem solving, and so on.

In the same way, our eyes also acts as an indicator to reveal our true feelings or in general, what our emotions are?

The answer is 'Pupil Dilation.'

What is Pupil?

Pupil is located in the centre of the iris of the eye. It is responsible for allowing the light to enter into the retina. It constricts when the light intensity is high and dilates when the light intensity is low or dim. Take a look at how the pupil really is from figure (2):


Figure 2: Showing the picture of Pupil

Now coming back to our area on how the state of pupil reveal the emotion of an individual?

Be attentive, assimilate and digest all the information I've prescribed below:-

Pupil will dilate or contract as you attitude and mood change from positive or negative and vice versa. 

  • When you are excited your size of the pupil will increase up to four times. Whereas, when you experience a negative option it 'contracts' and we call it 'snake eyes.'

This was confirmed by a famous psychologist Eckhard Hess who said, "Pupil size is affected by one's general state of arousal." He conducted a study on a group of individuals comprising of both men and woman. The individuals were told to watch a set of both pleasant and unpleasant images; like a baby, war, foods, violent scenes,  etcetera. The findings are: 

  1. Individuals pupil dilated when they watched a pleasant picture like baby, their favourite food, etcetera. And also, woman's eyes dilated faster than men.
  2. Individuals pupil contracted when they watched images of war scenes, violence, and so on.

This study gives us a strong confidence on how the pupil behaves in different scenarios.

In courtship, If a woman is more attracted to a man, she will dilate her pupils at him. This is the reason, "Why romantic encounters are successful in dimly lit places, because everyone's pupils dilate; and create an impression of interests with each other." In a nut shell, both the partners unconsciously perceive each other as appealing and interesting.

Is there a possibility to dilate our pupils artificially? 

The answer is 'Yes'. There is a drug called 'Belladonna'  which stimulates the dilation of pupil. Various studies convey that, prostitutes use this substance to dilate their pupil to make them appealing. This is may also be used by actors or sellers in advertisement to make them attractive. 

An interesting point to note is, "Men find woman with dilated pupil as more attractive". This is the reason why myriad of magazines use woman with dilated pupils as their cover page. Take a look at this example in figure(3):


Figure 3: Showing the examples of dilated pupils on the cover page of magazines.

Studies have also confirmed that when person arrives a solution for a problem their pupil will start to dilate. Moreover, few people's pupil dilate when they listen to their favourite music.

Here an example of the famous celebrity with her dilated pupils figure(4):


Figure 4: Showing the dilated pupils of Angelina Jolie

Here's an exercise for you:

  1. Guess her emotion or situation she experiences in figure 4.

Now go back to figure 1. And which of the two images is more attractive to you. The first or the second?

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  1. Pupil either dilates or contracts with respect to positive or negative experiences.
  2. Belladonna stimulates pupil dilation.
  3. Pupil dilates at dim light and contracts under high light intensity.
  4. Research by Eckhard Hess.
  5. Interesting facts and scenarios.


"True knowledge begins by asking questions and discussing ideas"

Share your views and ideas with me. 

-B. Saravanan

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