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Does our emotional state affect our vision?


Does our emotional state affect our vision?

There are many common phrases that suggest that our vision can be affected by our mood or emotions. Everyone would be familiar with such phrases such as ‘rose-tinted glasses’, ‘green-eyed’ and ‘eye-opening’.

Such terms form part of our everyday language, but it now appears that there is evidence to suggest that our emotional state can actually influence our vision.

Both the Journal of Neuroscience and the Scientific American magazine have researched the subject and report that behavioural studies indicate there is a clear link between what we are thinking and how we see the world.

Scientists have known for more than a century that the pupils of the eye respond to more than just light – they also reveal signs of mental and emotional significance. But it’s only in recent times that we’ve been able to understand more about it.

What actually happens with eyes and emotions?

Stimulation of the body’s autonomic nervous system can cause either dilation or constriction of the pupils, so they reflect some type of emotional response at any given time. In fact, it seems that the amount of pupil response resulting from mental effort is even more acute than expected and incredibly precise.

Princeton University psychologist, Daniel Kahneman, has demonstrated that the change in pupil size is directly related to the degree of difficulty of any given task.1 For example, a difficult mathematical sum will increase the size of the pupils until the solution is found and then they will begin to shrink. Equally, the pupils will also constrict if the person has decided that they can’t answer a question and relinquish the task.

The same principle applies to many other mental states: sleepiness, introversion, race bias, moral judgements, sexual interest and many other emotionally-charged subjects can all be assessed by pupil size, using a measurement known as pupillometry.

What’s more, pupil dilation can announce a person’s decision before they actually say it. In a study at Philipps University in Marburg, Germany conducted in 2010, participants were asked to press a button at any point in time during a 10-second period.1 What was found was that the dilation of each person’s pupil always occurred before they triggered the button, thereby pre-empting the physical response every time.

At the University of Toronto, another study was conducted to ascertain how mood affects vision. In this case, participants were shown a variety of images surrounding a human face.2 The respondents consistently provided more detailed and accurate information after viewing the more positive images – and less comprehensive information when the surrounding images were perceived as negative. The study confirmed that a positive mood quite literally increased our ability to see more – both our point of view and our perspective was broadened.


From the result of many worldwide studies, it is now known that our pupils not only respond to our emotions but also pinpoint our thoughts both accurately and incredibly quickly. So much so, that an informed observer could almost read someone’s mind and know what the subject might be thinking before they announced it.

So, be warned – however carefully you choose your words, your eyes could reveal what you’re really thinking.


  • Scientific American (2012). Eye-opener: Why do pupils dilate in response to emotional states?Available at https://www.scientificamerican.com/article/eye-opener-why-do-pupils-dialate/.
  • Science Daily (2009). People who wear rose-coloured glasses see more, study shows. Available at https://www.sciencedaily.com/releases/2009/06/090603103807.htm

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The information on this page is general in nature. All medical and surgical procedures have potential benefits and risks. Consult your ophthalmologist for specific medical advice.

Date last reviewed: 2022-10-05 | Date for next review: 2024-10-05

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