Health & Science

The eyes have it

New research suggests the size of an individual’s pupils may relate to how intelligent they are

YOU can tell a lot by looking into someone’s eyes You can spot a glint of humour, if they are happy or sad; 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. Big ink.com reports that a study carried out at the Georgia Institute of Technology shows that pupil size is “closely related” to di erences in intelligence between individuals. e scientists found that larger pupils may be connected to higher intelligence, as demonstrated by tests that measured 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 scienti c 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. e connection was rst noticed across memory tasks, looking at pupil dilations as signs of mental e ort. e studies involved more than 500 people aged 18 to 35 from the Atlanta area. e subjects’ pupil sizes were measured by eye trackers, which use a camera and a computer to capture light re ecting o th e pupil and cornea.

As the scientists explained in the journal Scienti c 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 “ uid 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 ickering asterisk on another part of the screen. If a person pays too much attention to the asterisk, they might miss the letter. e conclusions of the research were that having a larger baseline pupil size was related to greater uid intelligence, having more attention control, and even greater working memory capacity, although to a smaller extent.

In an email exchange with Big ink, author Jason Tsukahara said: “It is important to consider that what we nd is a correlation — which should not be confused with causation.” e researchers also found that pupil size seemed to decrease with age. Older people had more constricted pupils but when the scientists standardised for age, the pupil-size-to-intelligence connection still remained. e 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 synthesising the hormone and neurotransmitter norepinephrine (noradrenaline), which mobilises the brain and body for action. Activity in the locus coeruleus a ects our perception, attention, memory, and learning processes.

As the authors explain, this region of the brain “also helps

‘As the scientists point out, their conclusions are controversial ... ”

maintain a healthy organisation 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 de cit hyperactivity disorder (ADHD). e researchers suggest 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.” is 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 ink, Tsukahara said:”If I had to speculate, I would say that it is people with greater uid intelligence that develop larger pupils, but again at this point we only have correlational data.”

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. e research team addresses this criticism by explaining that other studies had methodological issues and examined only memory capacity but not uid intelligence, which is what they measured.

It sounds fishy but this may help migraine sufferers

PEOPLE who routinely experience migraine headaches joined a clinical trial designed to test whether a special diet could alleviate their frequent migraine headaches. e diet to follow emphasised foods that contained large amounts of omega-3 fatty acids, the oils found in some sh, while limiting foods that are rich sources of omega-6 fatty acids, such as many vegetable oils.

Omega-3s and omega-6s are both considered essential fatty acids — critical for health, and because our bodies can’t make them, they must be obtained from foods.

Historically humans consumed roughly equivalent amounts of both fatty acids. But the typical diet today tends to contain a much larger proportion of omega-6 fats. Some health authorities see this as a good thing: Vegetable oils and other rich sources of omega-6 fats have been found in many studies to be bene cial for cardiovascular health.

But others argue that this could be problematic because omega-6 fats have been shown to promote pain and in ammation, while omega-3 fats tend to have the opposite e ect in studies, helping to reduce pain and in ammation. e authors of the new study wanted to know: Could a diet that boosts omega-3 fats while lowering omega-6 fats make life easier for people burdened by frequent migraine headaches? e bene ts of a change in diet were striking: After a few months of increasing sh intake and avoiding many common vegetable oils, the majority of participants noticed that their headaches had all but disappeared.

Migraine headaches are one of the most common causes of chronic pain, affecting about 12 percent of people, most of them women. For many people, the condition can be debilitating, causing intense pain, nausea and other symptoms and sharply increasing the likelihood of developing depression and anxiety.

Studies have found that migraine attacks can take a toll on workplace productivity, too, causing people to lose, on average, about four work days a year.

But the new study provides evidence that the right diet could provide relief to some people who experience frequent migraine attacks, helping them reduce the number and severity of their headaches. Similar studies are underway to assess whether dietary changes could help ease other kinds of painful chronic ailments, such as low back pain.

Dr Christopher E. Ramsden, the lead author of the study, said the ndings suggest that dietary changes could be a useful complement to existing treatments for chronic pain.