Jun 04, 2021 07:00:00

It is so different that the difference can be seen with the naked eye, which indicates the possibility that 'the larger the pupil size, the higher the intelligence'.

In addition to changing the size of a person's pupil in response to light, it also changes due to factors such as 'excitement,' 'interest,' and 'mental fatigue.' A new study shows that human pupil size may be associated with 'intelligence.'

Is baseline pupil size related to cognitive ability? Yes (under proper lighting conditions) --ScienceDirect

https://www.sciencedirect.com/science/article/abs/pii/S0010027721000627?via%3Dihub

Pupil Size Is a Marker of Intelligence --Scientific American
https://www.scientificamerican.com/article/pupil-size-is-a-marker-of-intelligence/

The Georgia Institute of Technology research team, which is conducting research, originally studied 'differences in mental effort required when a person completes a memory task', and used 'pupil size' as an index of mental effort. I was using it. This method was popularized in the 1960s and 1970s by Daniel Kahneman, who is known for integrating economics and cognitive science. During his research, he realized the possibility that the size of the pupil, which is the baseline, might differ depending on the level of intelligence.

Uncertain about the relationship between pupil size and intelligence, the research team decided to conduct an experiment with 500 subjects aged 18-35 years. First, the researchers placed a white screen in front of the resting subject and captured the subject's eye condition with an eye tracker for four minutes. And from the eye tracker records, the average pupil size of each subject was calculated. In this study, the definition of the pupil was 'the diameter of the black circular diaphragm in the center of the eye', and its size was within the range of 2 to 8 mm. The research team also notes that all subjects were passed through a dimly lit room in the experiment because the pupils resized in response to light.

After measuring the average pupil size, each subject has 'fluid intelligence', which is the intelligence to think about new problems, ' working memory capacity', which stores information for a certain period of time, and the ability to maintain concentration regardless of interference. We tested 'attention control ability'.

The results showed that the larger the mean pupil size at baseline, the higher the fluid intelligence and attention control ability. It has also been confirmed that the working memory capacity was correlated, although it was smaller than the other two.

The research team cites the finding that 'pupil size is negatively correlated with age' as an interesting point. In other words, as we got older, the size of our pupils became smaller. On the other hand, even if the experimental data were readjusted in consideration of age, the relationship between pupil size and cognitive ability was still shown. 'The difference in baseline pupil size between those who scored the highest and those who scored the lowest on the cognitive test was visible to the naked eye,' the research team said.

The research team explains that the reason why the pupil size increases with increasing intelligence is because

there is a relationship between the function of the locus coeruleus , a part of the brain, and the size of the pupil. The locus coeruleus is a group of nerve cells called the nerve nucleus , which is located in the upper brain stem and makes extensive nerve connections in the brain. The locus coeruleus is a neurotransmitter but also functions as a hormone and is involved in the secretion of noradrenaline, which controls perception, attention, learning, and memory. The locus coeruleus also plays a role in 'organizing brain activity' by working together with distant parts of the brain in order for humans to accomplish their tasks. When the locus coeruleus becomes dysfunctional, it is not possible to summarize brain activity, causing medical conditions such as Alzheimer's disease and ADHD. The organization of activity is very important to the brain, and much of the energy is devoted to it, the researchers say.

The relationship between cognitive function and pupil size is still in the research stage and no conclusions have been reached yet. However, the research team has one hypothesis that 'people with large pupil sizes have greater control over brain activity by the locus coeruleus.' The research team suspects that cognitive performance is high due to its great ability to organize brain activity, which may be beneficial to resting brain function.