Intelligence based on pupil size?

Looking directly into another person’s eyes can reveal a lot about them. In fact, poker players often cover their eyes with sunglasses for fear of giving a tell, and some studies have shown that staring into another person’s eyes can create deep feelings of intimacy for those involved.

Now, it turns out, a person’s eyes might also reveal something unexpected and controversial: their level of intelligence, reports Discover.

In the new study, psychologist Jason S. Tsukahara and colleagues found a positive correlation between pupil size and cognitive ability. Of course, dilated pupils occur when the eye needs to let in more light, such as when you need to adjust to the dimmer light of a dark room. But what could having larger-than-average pupil size have to do with IQ? It turns out, changes in pupil size happen in a number of circumstances that don’t necessarily relate with changes in light levels.

“Starting in the 1960s, it became apparent to psychologists that the size of the pupil is related to more than just the amount of light entering the eyes. Pupil size also reflects internal mental processes,” wrote the researchers. “For instance, in a simple memory span task, pupil size precisely tracks changes in memory load, dilating with each new item held in memory and constricting as each item is subsequently recalled.”

So could this mean that people with generally larger pupils have more active minds? It’s certainly possible, but as any serious scientist will tell you, correlation does not necessarily equal causation. The researchers suggested another possibility: that both intelligence and pupil size might be influenced by some other shared factor.

“Neuroscience research has shown a close association of pupil size with activity in the locus coeruleus-norepinephrine system. [In the brain, norepinephrine] modulates the gain of target neurons to be more sensitive to incoming signals (both excitatory and inhibitory)… this modulation of neural gain has an effect on the strength of functional connectivity throughout the brain,” they wrote.

In other words, it’s possible that the key factor here is higher norepinephrine signaling. It would make sense that more intelligent people should be more sensitive to excitatory and inhibitory signals in the neural system. If higher norepinephrine levels are also correlated with larger pupil size, then the connection makes sense.

Of course, the study will need to be expanded to make sure the correlation does, in fact, exist. And it should also be noted that there are many other factors that relate to IQ than pupil size or norepinephrine signaling, so these factors hardly make for a conclusive intelligence test. Still, it’s an interesting twist on the old notion that the eyes are the windows to the soul.

source: Bryan Nelson

Why can we sense when people are looking at us?

If you’ve ever felt like someone was watching you, you may have attributed that awareness to a sense of unease or a prickling on the back of your neck. But there’s nothing psychic about it; your brain was simply picking up on cues. In fact, your brain is wired to inform you that someone is looking at you — even when they’re not.

“Far from being ESP, the perception originates from a system in the brain that’s devoted to detecting where others are looking,” writes social psychologist Ilan Shrira. This concept may sound confusing, but it actually makes a lot of sense when you think about it as a survival instinct.

Many mammals can tell when another animal is looking at them, but the human “gaze-detection system” is particularly good at doing this from a distance. We’re able to easily discern where someone is looking.

This system is especially sensitive when someone is looking at you directly, and studies have found that particular cells fire when this happens.

“Gaze perception — the ability to tell what someone is looking at — is a social cue people often take for granted,” Colin Clifford, a psychologist at the University of Sydney’s Vision Center, told the Daily Mail. “Judging whether others are looking at us may come naturally, but it’s actually not that simple as our brains have to do a lot of work behind the scenes.”

When you catch someone looking at you, what is it that clued you in? Often, it’s as simple as the position of the person’s head or body.

If both the head and body are turned toward you, it’s clear where the person’s attention is focused. It’s even more obvious when the person’s body is pointed away from you but their head is facing you. When this happens, you immediately look to the person’s eyes to see where they’re looking.
Human eyes are different from those of other animals in this regard. Our pupils and irises are darker from the white part of the eyeball known as the sclera, and this contrast is why you can tell when someone’s looking at you or simply looking past you.

Other species have less visible sclera, which is advantageous for predators that don’t want their prey to know where they’re looking. However, human survival is more dependent on communication, which is why we evolved to have larger, white sclera, which help us make eye contact.

But when head and body positions don’t provide much information, research shows that we can still detect another person’s gaze extraordinarily well because of our peripheral vision.

We evolved to be this sensitive to gaze to survive. Why? Because every look someone throws your way is a potential threat.

Clifford tested this by asking study participants to indicate where various faces were looking. He found that when people couldn’t determine the direction of a gaze — because of dark conditions or the faces were wearing sunglasses — people typically thought they were being watched.

He concluded that in situations where we’re not certain where a person is looking, our brain informs us that we’re being watched — just in case there’s a potential interaction.

“A direct gaze can signal dominance or a threat, and if you perceive something as a threat, you would not want to miss it,” Clifford said. “So simply assuming another person is looking at you may be the safest strategy.”

credit: Laura Moss

What your eye color says about you

Your eyes can be a window into your soul, and some say that your eyes — be them baby blue, sexy green or deep, mysterious brown — may reveal even more.

Like how well you tolerate pain. Or your tendency toward alcohol dependence. Or just how generally agreeable you might be.

Eye color and what eye color really means are a constant source of fascination among scientists, academicians and that guy or girl across the bar. As is often the case with these things, though, it’s not that simple. In fact, it gets pretty complicated.

What you see is what you get

“This general question of the relationship between, say, a visible trait — height or body size, or skin color or eye color or hair color — and anything else, whether it’s a disease trait or whether it’s a visible trait, is something that geneticists think about and talk about all the time. And it’s a topic of understandable popular interest,” says Greg Barsh, a faculty investigator at HudsonAlpha Institute for Biotechnology, a nonprofit based in Huntsville, Alabama, and a professor emeritus of genetics at Stanford University.

“We do not think, we do not believe that there is a direct connection of eye color with specific diseases. We do not think that there is a relationship, say, between eye color and diabetes, or eye color and cancer, or eye color and behavior.”

Still, many people are all too willing to make that link between the color of someone’s eyes and, say, how well they react in a motor skills test. (Men with dark eyes reportedly performed better than those with lighter-colored eyes — but only when they blue racquetballs, rather than green or yellow.)

Are light-eyed people from a certain region, for example, really less agreeable than the dark-eyed population of the same region, as one study suggests?

It’s easy to accept the hypothesis of this study, which concludes that “light-eyed individuals have a higher prevalence of [alcohol dependency] than dark-eyed individuals.” Or this piece in Cosmopolitan, based on several popular papers, that concludes:

Brown-eyed people are prone to anxiety.
Green-eyed folks have a higher tolerance for pain.
Those with blue eyes have a lower risk of anxiety and depression, yet are more likely to be dependent on alcohol.
Easy, sure. But believable? Can you really make that jump, that generalization, based solely on the color of someone’s eyes? Or is it, as Barsh suggests, more complicated?
Ancestry, cause and correlation

“Most individuals with blue eye color are of North European ancestry. But there are many other traits that are also correlated with North European ancestry,” Barsh says. “So when someone says, ‘Okay, I looked at a bunch of people with blue eyes and I also discovered that they drive faster, or they die sooner, or that they have a difference in pain tolerance,’ … the default question that always must be asked is, ‘How do you know that isn’t a difference that is genetic and happens to be related to their North European ancestry?'”

Barsh cites an old example popular among geneticists: A discovery is made that people in the Bay Area of San Francisco are more adept, as a whole, at using chopsticks than people in many other areas of the country. Is that because, simply, they[re from the Bay Area?

Or is it because many people from Asia, or many people with ancestors from Asia, have settled in the San Francisco area, and those ancestors were adept at eating with chopsticks?

“The situation with visible traits is actually pretty similar, because visible traits are highly, highly correlated with ancestry,” Barsh says. In other words, blue eyes are usually handed down from ancestors in North Europe. People with ancestors from Asia and Africa are normally dark-eyed.

Still, that doesn’t mean you can come to conclusions about diseases or behaviors just based on ancestry, either.

“One of the major challenges that I think all biologists face is distinguishing correlation from causation,” Barsh adds. “If you have two traits found in one group but not another, it can be very challenging to distinguish whether the relationship between the traits is that one causes the other, or they just happen to be present in the same population.”

So to do this thing right, you have to dive deeply into the genetics of a given population. And genetics are a complicated thing. There’s one main gene — it’s called the OCA2 — responsible for eye color, for example. But several other genes contribute. So assigning a behavior, or the chance of getting a disease to, say, the OCA2 and four or five other genes (among some 20,000 in humans) falls a bit on the simplistic side.
“We know enough about the genes that control skin and eye color that [we know] that is, in fact, all that they do. They don’t do other things,” Barsh says. “No matter how much we learn, we’re never going to learn that eye color has anything to do with intelligence. We know that it doesn’t. It doesn’t have anything to do with behavior. It doesn’t have anything to do with disease susceptibility.”

The only exception, it seems, is that those with lighter skin and lighter eyes are more susceptible to the damaging effects of ultraviolet rays from the sun, which could lead to diseases of the eyes and skin.

Other than that, though, the color of those baby blues is that and only that: A color (or lack of, or a combination of colors) based on genes handed down from your ancestors.

Anything else may just be your eyes playing tricks on you.

Credit: John Donovan

Eyes may be the windows to heart health

Vision problems may sometimes be the only symptom a person has of a serious cardiovascular condition, a new case report suggests.

In the case, a 77-year-old man in Greece experienced three short episodes of blurred vision in his right eye. The five-minute episodes stretched over an hour in total, and after each episode, his vision returned to normal.

An eye exam showed that the man’s vision was good, and the pressure within his eyes was normal. But when the man’s pupils were dilated and a doctor looked more closely into his eyes, the culprit was revealed: A blood clot was blocking the blood supply in a branch of his retinal artery, which supplies blood to the lining at the back of the eye, according to the report of the man’s case.

Such clots are typically made out of cholesterol and clumps of platelets (blood cell fragments), and in the case, the clot came from the man’s carotid artery, the main artery that brings blood to the head and neck, said Dr. Ilias Georgalas, an assistant professor of ophthalmology at the National and Kapodistrian University of Athens, in Greece.

But the tiny clot was a serious health problem — people with a blockage in the eye’s central or branch retinal artery have a high risk of a serious or fatal stroke, said Georgalas, who treated the man and was one of the co-authors of the case report published online Nov. 25 in the New England Journal of Medicine.

Vision problems and heart disease

The 77-year-old man had no history of eye problems, but he had high cholesterol levels and had been taking statin drugs for the past five years to reduce his cholesterol.

The man was diagnosed with “amaurosis fugax,” a condition in which a person loses vision in one eye, usually for a few minutes at a time, because of an interruption of blood flow in an artery.

The clot in the man’s eye was a fragment of a plaque that had formed in the man’s right carotid artery, and then traveled through his bloodstream and landed in one of the smaller branches of the retinal artery in his eye, Georgalas said. This temporarily closed off the blood supply to his right eye, which explains the man’s blurred vision, he said.

Examining the eyes is an easy way for doctors to have a look at the vascular system, the network of blood vessels in the body, which includes the arteries and veins, Georgalas said. It’s very rare for a vascular problem in other parts of the body to not be seen in the blood vessels within the eyes, he said.

For this Greek man, his blurred vision led doctors to detect that the blood flow through his right internal carotid artery was 80 percent blocked because of atherosclerosis, or hardening of the arteries.

He needed a carotid endarterectomy, a surgical procedure that removes plaque buildup in a narrowed artery, and can prevent a stroke. Twelve months later, the man’s vision was normal and he had no eye problems, according to the case.

For a relatively high number of people with severe carotid artery blockage, temporary visual loss may be the only symptom, Georgalas said.

Any temporary, painless loss of vision should not be ignored, he said. The eyes can provide a good indication of a person’s health throughout the body, and visiting an ophthalmologist can often be the first step in diagnosing more severe health problems, Georgalas noted.

Credit: Cari Nierenberg

Men and woman literally see the world differently

A new study shows that the sexes really do see the world differently. Men notice small details and moving things while women are more sensitive to color changes.

Guys’ eyes are more sensitive to small details and moving objects, while women are more perceptive to color changes, according to a new vision study that suggests men and women actually do see things differently.

“As with other senses, such as hearing and the olfactory system, there are marked sex differences in vision between men and women,” researcher Israel Abramov, of the City University of New York (CUNY), said in a statement. Research has shown women have more sensitive ears and sniffers than men.

“A recent, large review of the literature concluded that, in most cases females had better sensitivity, and discriminated and categorized odors better than males,” Abramov and colleagues write Tuesday (Sept. 4) 2015 in the journal Biology of Sex Differences.

Abramov and his team from CUNY’s Brooklyn and Hunter Colleges compared the vision of males and females over age 16 who had normal color vision and 20/20 sight — or at least 20/20 vision with glasses or contacts.

In one part of the study, the researchers asked the volunteers to describe different colors shown to them. They found that the guys required a slightly longer wavelength of a color to experience the same shade as women and the men were less able to tell the difference between hues. [Your Color Red Really Could Be My Blue.

The researchers also showed the participants images made up of light and dark bars that varied in width and alternated in color so that they appeared to flicker, a measure of participants’ sensitivity to contrast. Compared with the women, the male volunteers were better able to identify the more rapidly changing images made up of thinner bars, the researchers said.

Abramov explained in a statement these elements of vision are linked to specific sets of thalamic neurons in the brain’s primary visual cortex. The development of these neurons is controlled by male sex hormones called androgens when the embryo is developing into a fetus.

“We suggest that, since these neurons are guided by the cortex during embryogenesis, that testosterone plays a major role, somehow leading to different connectivity between males and females,” Abramov said. “The evolutionary driving force between these differences is less clear.”

Previous research found that men and women also focus differently. In experiments at the University of Southern California, researchers found that men are likely to fixate on the mouth of a person in conversation and also are more likely to be distracted by movement behind that person. Meanwhile, women tend to shift their gaze between a speaker’s eyes and body, and they are more likely to be distracted by other people, the researchers found.

credit/source: livescience

 

10 crystals and stones that make you healthier

1. Turquoise helps you heal.

Turquoise is the master healer. It is believed to be the energetic bridge between heaven and earth. Since ancient times, it’s been highly regarded for its protective and good-luck-charm properties. It’s believed that when Turquoise is given as a gift, its healing properties are magnified by one hundred! Turquoise is a stone of communication that helps you to speak your truth, from the highest source of love.

2. Bloodstone gives you energy.

In ancient times, Bloodstone was often worn as an amulet to help purify the blood. When our blood and energy is flowing smoothly, our life force remains strong and healthy. This crystal is a powerful energizer, helping you to overcome lethargy, negative thoughts and self-doubt. Bloodstone also helps to boost enthusiasm, increase drive and maintain emotional wellbeing.

3. Smoky quartz helps you let go.

Smoky quartz transmutes negative energy and acts as a protective shield against unwanted energy. It helps you to let go of old patterns and belief systems that are holding you back. It releases all blocked, old and stagnant energy in the body. Once all of your old energy is removed, new energy is able to fill the open space with light and hope.

4. Rose quartz cultivates love.
Rose quartz is a stone of unconditional love that helps to open and heal the energy of the heart. It encourages the forgiveness of others and, most importantly, of yourself. The secret to finding true love is to love yourself. Rose quartz emits vibrations of love, beauty and compassion. It’s a feel-good stone that nurtures, supports and allows you to feel the most powerful energy in the universe: LOVE.

5. Carnelian is good for creativity.
Ancient civilizations believed that carnelian attracted fortune and helped you attract your deepest desires. It removes blocked or stuck creative energy that may be dominating your mind and leaving you feeling burnt out or uninspired. Its vibrant orange color stimulates your passion to move forward and achieve your dreams. Carnelian is an action stone that restores motivation, confidence and joy.

6. Quartz crystal works wonders in clearing the mind.
Quartz crystal is made of silica, the most abundant element on the earth. It also makes up the human body, on a cellular level. When quartz crystal touches your skin, a merging of energy occurs, which is believed to encourage optimal health and healing. Ancient civilizations utilized quartz to balance the body and clear the mind. It’s a powerful crystal that transmutes negativity and amplifies energy to raise your vibration and help you align with light and clarity.

7. Celestite relieves stress.
Celestite’s name is derived from the Latin word caelestis, meaning celestial. By simply gazing upon it, the heavenly blue color of this crystal inspires deep peace and happiness. It’s an ideal crystal to place in your bedroom to bring tranquility and harmonious energy, encouraging restful sleep. When placed directly on your body, celestite brings muscle and stress release to the area on which it is placed.

8. Citrine helps to live in the now.
Citrine is a crystal of light and happiness. It doesn’t hold any negative energy and emits large amounts of positive energy. It serves as a friendly reminder to be present and in the now, because in this moment, you can create miracles. Citrine is a manifestation stone that encourages you to dream big, maintain a positive state of mind and attract everything you want in your life.

9. Aventurine attracts new opportunities.
Aventurine helps you to overcome feelings of self-doubt. It opens up the energy of the heart, attracting new opportunities. It helps to increase confidence, self-worth and optimism. As your mind and energy field open up, you are able to see the infinite abundance and opportunities that surround you.

10. Shungite protects against EMF.
Believed to be millions of years old, Shungite is an ancient crystal that is found in Russia. Scientists are still currently researching the full potential of this magical mineral. It’s utilized as a powerful shield against electrical magnetic energy (EMF). Shungite helps to absorb negative energy and pollutants. Place a piece of Shungite next to computers or wear on your body as an energetic shield.