Pupil size surprisingly linked to differences in intelligence

What can you tell by looking into someone’s eyes? You can spot a glint of humor, signs of tiredness, or maybe that they don’t like something or someone. 

But outside of assessing an emotional state, a person’s eyes may also provide clues about their intelligence, suggests new research. A study carried out at the Georgia Institute of Technology shows that pupil size is “closely related” to differences in intelligence between individuals. 

The scientists found that larger pupils may be connected to higher intelligence, as demonstrated by tests that gauged reasoning skills, memory, and attention. In fact, the researchers claim that the relationship of intelligence to pupil size is so pronounced, that it came across their previous two studies as well and can be spotted just with your naked eyes, without any additional scientific instruments. You should be able to tell who scored the highest or the lowest on the cognitive tests just by looking at them, say the researchers.

The pupil-IQ link

The connection was first noticed across memory tasks, looking at pupil dilations as signs of mental effort. The studies involved more than 500 people aged 18 to 35 from the Atlanta area. The subjects’ pupil sizes were measured by eye trackers, which use a camera and a computer to capture light reflecting off the pupil and cornea. As the scientists explained in Scientific American, pupil diameters range from two to eight millimeters. To determine average pupil size, they took measurements of the pupils at rest when the participants were staring at a blank screen for a few minutes.

Another part of the experiment involved having the subjects take a series of cognitive tests that evaluated “fluid intelligence” (the ability to reason when confronted with new problems), “working memory capacity” (how well people could remember information over time), and “attention control” (the ability to keep focusing attention even while being distracted). An example of the latter involves a test that attempts to divert a person’s focus on a disappearing letter by showing a flickering asterisk on another part of the screen. If a person pays too much attention to the asterisk, they might miss the letter. 

The conclusions of the research were that having a larger baseline pupil size was related to greater fluid intelligence, having more attention control, and even greater working memory capacity, although to a smaller extent. In an email exchange with Big Think, author Jason Tsukahara pointed out, “It is important to consider that what we find is a correlation — which should not be confused with causation.”

The researchers also found that pupil size seemed to decrease with age. Older people had more constricted pupils but when the scientists standardized for age, the pupil-size-to-intelligence connection still remained.

Why are pupils linked to intelligence?

The connection between pupil size and IQ likely resides within the brain. Pupil size has been previously connected to the locus coeruleus, a part of the brain that’s responsible for synthesizing the hormone and neurotransmitter norepinephrine (noradrenaline), which mobilizes the brain and body for action. Activity in the locus coeruleus affects our perception, attention, memory, and learning processes.

As the authors explain, this region of the brain “also helps maintain a healthy organization of brain activity so that distant brain regions can work together to accomplish challenging tasks and goals.” Because it is so important, loss of function in the locus coeruleus has been linked to conditions like Alzheimer’s disease, Parkinson’s, clinical depression, and attention deficit hyperactivity disorder (ADHD).

The researchers hypothesize that people who have larger pupils while in a restful state, like staring at a blank computer screen, have “greater regulation of activity by the locus coeruleus.” This leads to better cognitive performance. More research is necessary, however, to truly understand why having larger pupils is related to higher intelligence. 

In an email to Big Think, Tsukahara shared, “If I had to speculate, I would say that it is people with greater fluid intelligence that develop larger pupils, but again at this point we only have correlational data.”

Do other scientists believe this?

As the scientists point out in the beginning of their paper, their conclusions are controversial and, so far, other researchers haven’t been able to duplicate their results. The research team addresses this criticism by explaining that other studies had methodological issues and examined only memory capacity but not fluid intelligence, which is what they measured.

Link Original: https://bigthink.com/surprising-science/pupil-size-intelligence


3 Nobel-Prize Discoveries For Better Memory

How is it possible to remember our wedding day, but not where we left our glasses? Here’s the deal… The hippocampus part of the brain which transforms memories from short term to long term often becomes inflamed with age. This can lead to short-term memory loss, or frustrating “senior moments”. So what can be done? The answer comes down to 3 Nobel Prize-winning breakthroughs for better memory. One of them is the discovery of a protein called Nerve Growth Factor (or NGF), which has been shown to protect the brain from inflammation & help with age-related memory loss.It’s what Dr. Rita Levi-Montalcini (103) used to obtain a greater mental capacity today than when she was 20 years old!Here’s how to easily boost it: 👉https://advbio.co/fb/amf-mb



Common class of drugs linked to increased risk of Alzheimer’s disease

A team of scientists, led by researchers at University of California San Diego School of Medicine, report that a class of drugs used for a broad array of conditions, from allergies and colds to hypertension and urinary incontinence, may be associated with an increased risk of cognitive decline, particularly in older adults at greater risk for Alzheimer’s disease (AD).

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O primeiro estudo da referência concluiu que a desidratação teve efeitos negativos no vigor, autoestima, memória de curto prazo e atenção. A reidratação, porém,atenuou esses efeitos. O segundo é o maior e mais abrangente estudo controlado a examinar como o estado de hidratação interfere no desempenho cognitivo. Inédito ao avaliar a questão em uma população com idade mais avançada, sendo os resultados negativos significativos para as mulheres. A atenção sustentada, velocidade de processamento, memória de trabalho e motricidade foram examinadas. Os cientistas responsáveis pela pesquisa evidenciaram também que a hiperidratação, particularmente se resultar em hiponatremia, pode ser tão preocupante para a função cognitiva como a desidratação. 🧠💦🗯 Esse e outros temaa relcaionados serão abordados no módulo Saúde & Alta Performance Cerebral da @mybrainuniversity

A desidratação afeta a motrocidade


Where stress lives

Yale researchers have found a neural home of the feeling of stress people experience, an insight that may help people deal with the debilitating sense of fear and anxiety that stress can evoke, Yale researchers report May 27 in the journal Nature Communications.

Brain scans of people exposed to highly stressful and troubling images — such as a snarling dog, mutilated faces or filthy toilets — reveal a network of neural connections emanating throughout the brain from the hippocampus, an area of the brain that helps regulate motivation, emotion and memory.

The brain networks that support the physiological response to stress have been well studied in animals. Activation of brain areas such as the hypothalamus triggers production of steroid hormones called glucocorticoids in the face of stress and threats. But the source of the subjective experience of stress experienced by people during the COVID-19 pandemic, for instance, has been more difficult to pinpoint.

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Exercise improves memory, boosts blood flow to brain

 

Scientists have collected plenty of evidence linking exercise to brain health, with some research suggesting fitness may even improve memory. But what happens during exercise to trigger these benefits? New UT Southwestern research that mapped brain changes after one year of aerobic workouts has uncovered a potentially critical process: Exercise boosts blood flow into two key regions of the brain associated with memory. Notably, the study showed this blood flow can help even older people with memory issues improve cognition, a finding that scientists say could guide future Alzheimer’s disease research.

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How to Work with Traumatic Memory That Is Embedded in the Nervous System

Long after danger has passed, the nervous system may still remember trauma. . .

. . . which can leave clients feeling hypervigilant, dissociative, or numb for years to come.

So to help clients heal, we need to understand what makes traumatic memory so overwhelming, and the most effective ways to work with it.

Not only that, we need strategies so clients can “unlearn” the nervous system’s response to trauma.

That’s why we created a course that focuses solely on how to work with traumatic memories that get embedded in the nervous system.

Three of the world’s top experts will share how they treat clients who have experienced trauma. This new program brings together their sharpest strategies for working with traumatic memory.

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Acetylcholine Supplements: Benefits, Side Effects, and Types

In recent years, nootropics, also called smart drugs, have gained popularity among people looking to improve their mental performance.

Acetylcholine is a neurotransmitter, or brain chemical, that plays a role in many key aspects of brain function, such as memory, thinking, and learning.

While acetylcholine supplements don’t exist, supplements that may indirectly raise acetylcholine levels have become popular among people interested in nootropics as a way to enhance mental performance.

This article explores the benefits and side effects of acetylcholine supplements, and outlines the best types.

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