Our eyes can tell us a lot about ourselves. Now, a study that is an extension of a previous one published in 2016 , delves even more into what the size of our pupil can reveal to us. We already know that several factors influence the dilation of the pupil: an emotion (such as getting excited or showing interest in something), taking certain medications, the consumption of recreational drugs, when the lighting is dim, etc. But it can also determine a value on intelligence. This was determined by a new study that suggests that the basic size of the pupil may be related to fluid intelligence, a component of intelligence that is based on the ability to solve problems without depending on knowledge already acquired; that is, the ability of a person to adapt and face new situations in an agile way and without prior learning.
Do you have a dilated pupil at rest? You have more fluid intelligence
Work by scientists at the Georgia Institute of Technology (USA) suggests that pupil size at rest is closely related to individual differences in intelligence. The larger the pupils, the greater the intelligence, based on results measured by tests of reasoning, attention, and memory.
In three separate studies with more than 500 participants , researchers found that the difference in pupil size between the participants who scored the highest on cognitive tests and those who scored the lowest was significant enough to be detected with the naked eye.
“We used dilated pupils as an indicator of effort, a technique popularized in the 1960s and 1970s by psychologist Daniel Kahneman. When we discovered a relationship between initial pupil size and intelligence, we weren’t sure if it was real. or what it meant ”, the authors point out.
First, they calculated the average pupil size of each of the participants between the ages of 18 and 35, using a special tracking device with a camera connected to a computer. Generally, the constricted pupil is two to four millimeters in size – which is surrounded by the iris – and is fully dilated to eight millimeters. The participants then had to take a series of cognitive tests to assess their ability to stay focused and control their attention by being deliberately distracted, reasoning about new problems, and remembering new information. Also, the light in the lab was dark to prevent the pupils from contracting in response to the light.
To measure the diameter of the pupils, they used an eye tracker or oculometer, an instrument that captures the reflection of light from the pupil and cornea using a high-precision camera, which can determine where and how a person is looking.
The results
They found that those who had a ‘larger initial pupil size’ performed better on tests of attention, memory and reasoning. This suggests a strong link between the brain and the eye that the researchers hope to study in more detail in the future. At an older age, the pupil tended to be smaller and constricted, but regardless of it, the observed relationship between pupil size and cognitive abilities was the same.
In addition, they found that the size of the pupil is related to a region of the brain known as the locus coeruleus, located in the upper part of the brain stem that extends to the rest of the brain through neural connections. This zone releases a chemical that works like a hormone in the brain targeting regular processes like perception, attention, and memory, as well as helping distant regions of our thinking organ work together to complete complicated tasks.
The two study authors say, however, that more research is needed to explore this finding and determine why larger pupils are particularly associated with greater fluid intelligence and better control of attention.
Referencia: Jason S. Tsukahara, Randall W. Engle, Is baseline pupil size related to cognitive ability? Yes (under proper lighting conditions), Cognition, Volume 211, 2021, 104643, ISSN 0010-0277, DOI: https://doi.org/10.1016/j.cognition.2021.104643.
