Why Do Blue Eyes Have Big Pupils?

Why Do Blue Eyes Have Big Pupils
Why Do Certain Drugs Cause Dilated Pupils? – As mentioned earlier, the iris part of the eye has muscles that manipulate the pupils. The iris is the colored part of your eye that determines the color of your eyes. If you have a blue Iris, then you have blue eyes and so on.

  • Some drugs, however, tend to relax the muscles in our bodies.
  • So when someone is on certain medications, their muscles, including the iris muscles, will relax, causing the pupils to dilate.6 Another reason why some drugs cause dilated pupils is the interference with neurotransmitters,
  • Neurotransmitters are the brain chemical messengers that affect how your brain communicates with other parts of the body.

Some drugs are known to slow down these neurotransmitters, thus slowing down how the brain communicates with the iris to signify the changes in lighting. This applies to misused drugs such as cocaine, alcohol, some over-the-counter medications, and antidepressants.

Do blue eyes get more dilated?

Individuals with light coloured eyes (blue or green) will dilate faster than people with darker coloured eyes. Dilated pupils cause light sensitivity and difficulty focusing on near objects.

What do naturally big pupils mean?

Why Do Blue Eyes Have Big Pupils Credit: Erik Von Weber Getty Images Sign up for Scientific American ’s free newsletters. ” data-newsletterpromo_article-image=”https://static.scientificamerican.com/sciam/cache/file/4641809D-B8F1-41A3-9E5A87C21ADB2FD8_source.png” data-newsletterpromo_article-button-text=”Sign Up” data-newsletterpromo_article-button-link=”https://www.scientificamerican.com/page/newsletter-sign-up/?origincode=2018_sciam_ArticlePromo_NewsletterSignUp” name=”articleBody” itemprop=”articleBody”> It has been said that “the eyes are the window to the soul,” but new research suggests that they may be a window to the brain as well. Our pupils respond to more than just the light. They indicate arousal, interest or mental exhaustion, Pupil dilation is even used by the FBI to detect deception. Now work conducted in our laboratory at the Georgia Institute of Technology suggests that baseline pupil size is closely related to individual differences in intelligence, The larger the pupils, the higher the intelligence, as measured by tests of reasoning, attention and memory. In fact, across three studies, we found that the difference in baseline pupil size between people who scored the highest on the cognitive tests and those who scored the lowest was large enough to be detected by the unaided eye. We first uncovered this surprising relationship while studying differences in the amount of mental effort people used to complete memory tasks. We used pupil dilations as an indicator of effort, a technique psychologist Daniel Kahneman popularized in the 1960s and 1970s. When we discovered a relationship between baseline pupil size and intelligence, we weren’t sure if it was real or what it meant. Intrigued, we conducted several large-scale studies in which we recruited more than 500 people aged 18 to 35 from the Atlanta community. We measured participants’ pupil size using an eye tracker, a device that captures the reflection of light off the pupil and cornea using a high-powered camera and computer. We measured participants’ pupils at rest while they stared at a blank computer screen for up to four minutes. All the while, the eye tracker was recording. Using the tracker, we then calculated each participant’s average pupil size. To be clear, pupil size refers to the diameter of the black circular aperture in the center of the eye. It can range from around two to eight millimeters. The pupil is surrounded by the colorful area known as the iris, which is responsible for controlling the size of the pupil. Pupils constrict in response to bright light, among other things, so we kept the laboratory dim for all participants. In the next part of the experiment, participants completed a series of cognitive tests designed to measure “fluid intelligence,” the capacity to reason through new problems, “working memory capacity,” the ability to remember information over a period of time, and “attention control,” the ability to focus attention amid distractions and interference. As one example of an attention control test, participants had to resist glancing toward a bold, flickering asterisk on one side of a computer screen and instead rapidly look in the opposite direction to identify a letter. The letter would disappear within moments, so even a brief eye movement toward the flickering asterisk could result in missing it. Humans are primed to react to objects passing through their peripheral vision—it’s what once allowed us to spot a predator or prey—but this task required participants to redirect their focus from the flicking asterisk to the letter. We found that a larger baseline pupil size was correlated with greater fluid intelligence, attention control and, to a lesser degree, working memory capacity—indicating a fascinating relationship between the brain and eye. Interestingly, pupil size was negatively correlated with age: older participants tended to have smaller, more constricted, pupils. Once standardized for age, however, the relationship between pupil size and cognitive ability remained. But why does pupil size correlate with intelligence? To answer this question, we need to understand what is going on in the brain. Pupil size is related to activity in the locus coeruleus, a nucleus situated in the upper brain stem with far-reaching neural connections to the rest of the brain. The locus coeruleus releases norepinephrine, which functions as both a neurotransmitter and hormone in the brain and body, and it regulates processes such as perception, attention, learning and memory. It also helps maintain a healthy organization of brain activity so that distant brain regions can work together to accomplish challenging tasks and goals. Dysfunction of the locus coeruleus, and the resulting breakdown of organized brain activity, has been related to several conditions, including Alzheimer’s disease and attention deficit hyperactivity disorder. In fact, this organization of activity is so important that the brain devotes most of its energy to maintain it, even when we are not doing anything at all—such as when we stare at a blank computer screen for minutes on end. One hypothesis is that people who have larger pupils at rest have greater regulation of activity by the locus coeruleus, which benefits cognitive performance and resting-state brain function. Additional research is needed to explore this possibility and determine why larger pupils are associated with higher fluid intelligence and attention control. But it’s clear that there is more happening than meets the eye. Are you a scientist who specializes in neuroscience, cognitive science, or psychology? And have you read a recent peer-reviewed paper that you would like to write about? Please send suggestions to Mind Matters editor Gareth Cook, Gareth, a Pulitzer prize-winning journalist, is the series editor of Best American Infographics and can be reached at garethideas AT gmail.com or Twitter @garethideas.

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Does ADHD cause dilated pupils?

Individuals in the ADHD group exhibited a significantly larger tonic pupil diameter, and a suppressed stimu- lus-evoked phasic pupil dilation, compared to those in the TD group.

What is the fear of blue eyes?

Cyanophobia, fear of the color blue. Kastanophobia, fear of the color brown. Leukophobia, fear of the color white.

Are big pupils healthy?

Although it is normal for dilation to occur based on changes in light, mydriasis could be a sign of an eye injury or problem within the brain, like a head injury, tumor or stroke. Contact your healthcare provider if you experience any of the following: Dizziness, headache or confusion (signs of a stroke).

Are bigger pupils more attractive?

This story is from The Pulse, a weekly health and science podcast. Find it on Apple Podcasts, Spotify or wherever you get your podcasts, The videos go like this: Someone uses their phone to zoom in on their eye, and then thinks hard about a crush, a love interest, or even their current partner.

  • If their pupil dilates, then they’re really in love.
  • To Helen Fisher, biological anthropologist, senior researcher at the Kinsey Institute, and chief science adviser to the dating site Match.com, the interest in a test like this is only natural.
  • Of course, we all do want to know whether somebody is attracted to us, and here’s another way of figuring it out,” she said.

“I think this TikTok thing is quite ingenious.” Fisher hadn’t seen the videos before, but she thinks they may be on to something. “It’s beautiful the way the body works, you know, it really is. There’s so many ways that we let the world know who we are without language.” When we’re attracted to someone, Fisher said, it prompts a chemical rush that’s actually part of our fight or flight response.

  1. What’s going on is that when you’re thinking about somebody that you are in love with, that’s triggering activity of feelings in the limbic system in the middle of the head, that’s sending signals up to the hypothalamus, pumps out norepinephrine and epinephrine or adrenaline.
  2. And what the adrenaline does is it controls the iris muscle of the eye, and as that becomes activated, it pulls the pupil to become larger,” she said.

For human beings, love is a life-or-death issue. The region of our brain that produces feelings of romantic love is called the ventral tegmental area — VTA. “This little brain region, the VTA, lies right next to the factory that orchestrates thirst and hunger,” said Fisher.

  1. Thirst and hunger keep you alive today; romantic love drives you to form a partnership and send your DNA into tomorrow.” She said it’s not clear why some pupils dilate and some don’t in these videos.
  2. It could be something to do with how peaceful your partnership is, or how long you’ve been together.

But she’s interested in learning more. “I think somebody should go do it,” said Fisher. “Take older people who reported they’re madly in love and see what happens to the pupils!” Though a person’s dilated pupil can be a tell-tale sign of attraction, it’s a pretty subtle clue.

Many other creatures seem to express their willingness to mate much more openly. “For the rats, it’s ear wiggling and hopping and dancing to show that they are in that receptive window. For others, it’s changing colors, depending on the species. For others, it’s changing vocalizing, and so on,” said Nafissa Ismail, an associate professor of psychology at the University of Ottawa.

For many animals, Ismail said, there’s a short window in which the time is right for sex, so their signals tend to be more urgent. “Often, reproduction is limited to a specific period during the year. They need to spread their genes before being attacked by a predator and find a female that is receptive it needs to be pretty obvious that they are looking for a partner,” Ismail said.

  1. Humans, on the other hand, can afford to be a bit more subtle.
  2. We are luckily not limited to that, so we will copulate at other periods across the menstrual cycle that is not limited to ovulation,” Ismail said.
  3. Pupil dilation may be a little more understated than a peacock’s display or a koala’s mating call, but it basically accomplishes the same thing, said Lynne Honey, an associate professor specializing in learning and behavior at MacEwan University in Edmonton, Alberta.
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“There are studies that take a look at pupil dilation and demonstrate that faces with dilated pupils are perceived as more attractive,” Honey said. “So, we might not necessarily know consciously why that signal is important, but at an unconscious level we respond to it by finding those faces more appealing, and there’s a bunch of signals like that in humans, where you can’t even necessarily put your finger on it, but it’s still influencing our behavior.” So really, we don’t need TikTok — we may not realize it consciously, but our brains perform the pupil test for us all the time.

Why are my daughters pupils so big?

Seeing a pattern – Over the past two years, Glen Steele, O.D., has been tracking a marked increase in the magnitude of changes in pupil size and the number of children showing this pattern. An increase in pupil size does not happen in isolation, Dr. Steele says, so he also was concerned about what was happening with other body processes, such as accelerated heart rates, widened bronchial passageways, constricted blood vessels, perspiration and raised blood pressure.

He has linked this to children’s use of cellphones and tablets. He is not alone. “There are many individuals, groups and organizations looking at this phenomenon,” says Dr. Steele, long-time advocate for children’s vision. He has taught and provided patient care at Southern College of Optometry in Memphis, Tennessee, for 50 years.

In particular, Dr. Steele has taken note of enlarged pupils—extremely large pupils between 7 and 10 millimeters that may respond to light but not to accommodation—among some of the younger patients he sees. Enlarged or dilated pupils can be caused by a number of factors: medications, drug use, eye and brain injuries, recreational drug use and eye diseases.

  • But the consistent factor among his patients, he says, appears to be prolonged phone or tablet use.
  • In past years, I would see maybe one congenitally large pupil a semester,” Dr.
  • Steele says.
  • Now I see five or six a day in a pediatric population (our clinic defines pediatric as birth to 12 years of age).

This is a significant change in the number seen in a very short time frame. I have tried to link it to medications and other things but the most consistent has been device use. “I call this pattern of large pupil size defocus,” he says. “Pupils are smaller during focus and larger during defocus.

  1. One can imagine how a pattern of defocus could interfere with the ability to perform in the classroom and other activities requiring focus, such as school work.
  2. Because I have only noticed this pattern for the past 18 months to two years, I do not know what the long-term effects will be as there has been very little time to study it and its effects on other sympathetic body processes.

“Defocus only occurs when we’re scanning on social media or gaming,” Dr. Steele says. “If reading, there is more tendency to focus, but it is easy to tell when I walk into the room and take a look at pupils with my retinoscope. It is more scanning during social media or playing a game, in which you have to be aware of the ‘attackers’ in a video game coming from all directions.

You can’t stop and look at them or something will attack you from another direction. This is the origin of the defocus pattern. “When this pattern is present, one must suspect some type of video game syndrome,” he says. “The problem is not in the eye directly, but it is affecting sympathetic responses that are shown in the eye.” Other ocular and developmental consequences from extended screen time, according to Dr.

Steele, include:

Reduced stereopsis (depth perception). Reduced ability in accommodation testing. Even though the patient may respond to the plus or minus with accommodation, pupil size changes minimally. Does not show expected visual acuity during refraction testing. Reduced fine motor control when learning to write, depending on a child’s age. Reduced social interaction. The addictive patterns are similar to other addictions and are reaching alarming status.

Do people with autism have dilated pupils?

THIS ARTICLE IS MORE THAN FIVE YEARS OLD – This article is more than five years old. Autism research – and science in general – is constantly evolving, so older articles may contain information or theories that have been reevaluated since their original publication date. Why Do Blue Eyes Have Big Pupils Light response: Clinicians may be able to use a pupil’s reaction to light as an indicator of autism risk. The pupils of children with autism react to light more slowly and less efficiently than those of controls, according to a study published 18 December in the Journal of Autism and Developmental Disorders 1,

  • This sort of autonomic response — which reflects basic biological functions such as heart rate, and is easy to measure — may signal risk of autism and related disorders.
  • The researchers see a similar effect in children with other neurological disorders.
  • Autism is diagnosed using behavioral measures, but people with the disorder also show physiological differences from controls.
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Researchers hope that some of these differences may become biomarkers, assisting with diagnosis and serving as endpoints for treatments. Although many biomarker studies focus on brain function, alterations in the autonomic nervous system are also promising.

Children with autism may have an elevated heart rate and larger pupils, and may react to stress more readily than controls do 2, A 2009 study found that their pupils are slower to constrict when exposed to light than are those of controls 3, The new study looked at pupillary reflex in 152 children with autism, 116 controls and 36 children with other neurological disorders, such as Down syndrome and fragile X syndrome,

The researchers also measured heart rate to test whether alterations in pupil size match up with other measures of the autonomic nervous system. Children with autism and those with other neurological disorders are all slower to constrict their pupils than controls are.

  1. They also constrict their pupils less and do so for a shorter period of time.
  2. Children with autism have a faster heart rate than controls do, and the rate for those with other neurological disorders is faster still.
  3. For children with autism, but not the other two groups, a faster heart rate accompanies slower pupil contraction.

Medication use has no statistically significant effect on the pupillary reflex, the study found. Typically developing children speed up their pupillary reflex between 6 and 8 years of age, the study found. The researchers did not see the same trend for children with autism, suggesting differences in brain development.

Does anxiety make your pupils bigger?

How Anxiety Can Affects the Pupil of Your Eye Why Do Blue Eyes Have Big Pupils People think of anxiety as a mental condition. But anxiety affects your body as well. During periods of intense anxiety – especially during panic attacks – your entire body goes into fight or flight mode, and you go through some immediate physical changes as a response.

Does dilated pupils mean your turned on?

For over 50 years, scientists have documented that the pupils dilate in response to sexual arousal. Despite the potential importance of this cue for mate selection, however, extant data have focused almost exclusively on the perspective of the individual experiencing arousal.

Why do my pupils dilate when I look at someone?

– Eye contact has long been central to human interactions. Changes in emotion might cause pupil dilation. The autonomic nervous system triggers various involuntary responses during emotions, such as fear or arousal. Some research suggests that pupil dilation is one of these involuntary responses to arousal or attraction.

For example, one 2012 study recruited 325 men and women with varying sexual orientations. The researchers played erotic videos to the participants while monitoring their pupil size. The study found that erotic videos led to pupil dilation in the participants. The team showed that bisexual men and heterosexual women had dilated pupils in response to erotic videos that included people of either sex.

Another study, this time in the journal Evolution and Human Behavior, focused on associations between pupil dilation and sexual attraction. The researchers found that it was possible to determine sexual interest from the size and darkness of the pupils.

  • Pupil size also appears to respond to hormonal changes.
  • One study recruited 14 women to view arousing pictures on a computer screen on different occasions.
  • Half of the women were taking hormonal birth control pills.
  • Women not taking birth control pills had dilated pupils while viewing arousing pictures during ovulation.

This did not occur in women taking birth control pills. The study therefore suggests that hormonal changes could influence arousal and pupil dilation. There is also some evidence to suggest that pupil dilation may indicate trust. A study in the Proceedings of the National Academy of Sciences suggests that pupil size changes play a role in trust formation.

  1. It remains unclear why pupil dilation might be involved in attraction.
  2. It could be a result of hormonal changes.
  3. However, many other factors can also affect pupil dilation.
  4. For example, research also suggests that paying attention to something can influence pupil size.
  5. It could be easy to mistake paying attention for attraction.

More research in this area will be necessary to establish whether pupil dilation is a sign of attraction or a result of other factors, such as hormones or involuntary bodily responses.