Our pupils will not only respond to light, they will also reflect human states such as arousal, interest, or mental exhaustion and other states. The US Federal Bureau of Investigation (FBI) even uses pupil dilation to detect whether a person is lying.
Recently, a study conducted in the laboratory of the Georgia Institute of Technology, USA has shown that pupil size is closely related to differences in intelligence of individuals. From tests of reasoning ability, attention and memory, it can be deduced that the larger the diameter of a person's pupil, the higher his IQ. In fact, the scientists also found that between the subjects with the highest and lowest scores on a cognitive test, the difference in pupil size was also very different and could be important. directly to the naked eye.
This surprising association was discovered when studying differences in human brain power during memory tasks. In the past, we used to use pupil dilation to measure a person's mental effort. This view was popularized by psychologist Daniel Kahneman in the 1960s and 1970s. Thus, when researchers discovered that there was a definite relationship between the basic pupil size and intelligence proven, the scientific community still feels that this is not certain of its authenticity.
For the same reason, the researchers decided to come from the US city of Atlanta to recruit more than 500 volunteers from 18 to 35 years old, to conduct a larger study on the relationship between pupil size and intelligence. Initially, they measured the pupil sizes of these subjects with an eye-tracking device. This device can use high-performance cameras and computers to capture reflected light from the pupil and cornea to obtain relevant data.
The scientists measured the participants' pupil sizes by having them stare at a blank computer screen for four minutes and during breaks. During this time, the eye tracker recorded data, allowing the team to calculate each participant's average pupil size.
The fact that pupil size is actually the diameter of the black round hole in the center of the eye is between 2mm and 8mm. The pupil is surrounded by the colored area of the eye - the iris. In addition, because bright light constricts the pupils, the team kept all the subjects in the lab in a steady state of light.
Next, the participants had to complete a series of cognitive tests. These tests are designed to measure "flexible intelligence" (ability to solve new problems through reasoning) and "working memory capacity" (ability to solve problems) through reasoning, remembering information for a short period of time), and "attention control" (the ability to focus in a noisy environment).
For example, in an attention-control test, subjects had to resist looking at the flashing bold asterisks on one side of the computer screen, but had to quickly look in the opposite direction to identify a English letters. Since the letter disappears instantly, even if the participant only briefly glanced at the flashing asterisk, the letter was likely to be missed. Although humans have learned to use peripheral vision to respond to objects they see, and this skill allows us to effectively detect predators or prey, this task requires humans participants ignore the flashing of the asterisks and instead pay full attention to the letters.
The team found that larger pupil size was associated with higher flexible intelligence and attentional control and also had a small correlation with working memory, which gives found that there is a certain relationship between the brain and the eye. Interestingly, pupil size was negatively correlated with age: older participants tended to have smaller and narrower pupils. However, after normalizing for age, the aforementioned correlation between pupil size and cognitive ability persisted.
But why is pupil size related to intelligence? Before answering this question, we need to understand what is going on in our brains. First, the size of the pupil is related to the activity of the Locus coeruleus - a nerve nucleus located in the upper part of the brain stem that has extensive neural connections with other parts of the brain.
Second, Locus coeruleus will secrete Norepinephrine - both a neurotransmitter and a hormone in the brain and body. It can regulate processes such as perception, attention, learning, and memory. In addition, Locus coeruleus helps to keep brain activity in an orderly state, so that different brain regions can work together to accomplish tasks and goals. The dysfunction of Locus coeruleus leads to disruption of the brain's systemic functioning and has been linked to a variety of diseases, including Alzheimer's disease and attention deficit hyperactivity disorder.
In fact, the organization and arrangement of brain activities is so important that the brain must expend most of its energy to maintain normal functioning, even when we do nothing during this period, for example. like just staring at a computer or scrolling through a phone screen for a few minutes.
In addition, it is also hypothesized that people with larger pupils at rest have a stronger ability to regulate brain activity, which is good for cognitive function and brain function at rest. Of course, further studies are needed to explore this possibility and determine why larger pupils are associated with higher intelligence and better attention control. But clearly there are still too many questions and mysteries compared to what we have just discovered.
