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We're going to blow your mind.

National Geographic Channel's Emmy-nominated series Brain Games returns this summer with 10 new mind-blowing episodes! Host Jason Silva gets inside your head and shows you what's really going on in there with an intricate series of interactive experiments designed to mess with your mind and reveal the inner-workings of your brain. Hailed by critics as "tremendous fun" that "makes science entertaining," Brain Games turns your mind's eye inwards for a fascinating journey into the three and a half pounds of tissue that makes you... you.

The Host Jason Silva

Described as a "Timothy Leary for the viral video age," Jason Silva is a self-proclaimed "wonder junkie" whose series of noncommercial videos exploring inspiration, science, technology, and imagination have been seen more than 2 million times online.

Host Jason Silva
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How much do you know about color and how it affects us? Complete all episode challenges to grade your brain.

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Question 1 of 3
Which of these colors fills you with a sense of trust?
Question 2 of 3
Which of these fruits could never truly be red?
  • Orange
  • Lemon
  • Apple
  • Kiwi
Question 3 of 3
Approximately what percentage of the population is color-blind?

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Get ready to color outside the lines.
Think you understand the colors you see every day? Think an apple is actually red, or a leaf is really green? Think again. This episode of Brain Games puts your brain to the ultimate test with a series of interactive games and fascinating experiments that will reveal a shocking truth—color is just an illusion created by your brain. We'll show you how some colors can make you fly, reveal ghostly colors that don't actually exist, and if you play along you’ll see how color helps keep you alive.
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The Colors of Your Mind

Your brain sees colors even when they're not there.

When we see a banana, we see it as yellow. That's no big surprise, right? Well, here's one for you. We see a banana as yellow, even when it isn't.

In a recent study, German neuroscientists showed subjects black-and-white pictures of bananas—along with similar images of broccoli, strawberries, and other items that have familiar colors—and then used scans to observe how the subjects' brains responded. Then they showed pictures of abstract rings in the same colors as the bananas and other items, for comparison. As it turned out, the black-and-white pictures of the bananas elicited the same patterns of neural activity which occurred when the subjects were viewing the yellow-colored ring. And not only did the subjects see colors that weren't there, but the perception occurred in the visual cortex, the region of the brain where information from sight first arrives.

"This result shows that higher-level prior knowledge—in this case of object-colors—is projected onto the earliest stages of visual processing," researcher Andreas Bartels explained.

Color exerts a profound influence upon how we see the world around us, and throughout history, various hues have taken on important social and psychological significance. That makes it all the more puzzling to realize that the colors that we perceive inside our brains—and the significance that we attach to them—sometimes diverge from the wavelengths of light that exist in reality. But recent scientific discoveries shed new light upon the mysteries of color perception, and help explain why color plays such an important role in our lives.

The Science of Color

Primates, including humans, have pretty good color vision compared to a lot of other animals, which probably gave us and our hairier cousins an evolutionary advantage in hunting and in finding wild fruit and other plant-based food. But whether we're looking at blueberries or at a painting from Pablo Picasso's "Blue Period" in a museum, what we actually perceive is electromagnetic energy, emitted by a source such as the Sun or an electric light fixture, and then reflected off other objects in the environment. But we can't see all the energy that's bouncing around in our environment. Visible light amounts to only a narrow swath in the middle of the electromagnetic spectrum—frequencies between 400 and 700 nanometers.

"At the most basic level color is light and light consists of electromagnetic waves," explains Yale University psychologist Brian Scholl, who heads the school's Perception and Cognition Laboratory. "But we can only see these waves when they're of the right length. A little bit too long and we call them microwaves. They're useful for heating up your hot pocket, but not so much for seeing. A little bit too short and we call them x-rays, but right in the middle, the part of the spectrum we call visible light, that's the most useful."

Various frequencies of light create colors—blue light, for example, has a wavelength of about 475 nanometers, while at the longer end, red has a wavelength of 650 nanometers. All of these frequencies are mixed together in sunlight, so that if we just saw the blend, everything would look white. Instead, though, light is filtered through the atmosphere, and then encounters objects, which allow the light to pass through, reflect it, or absorb it—or some combination of these effects. For example, a plant leaf may absorb long and short frequencies of light and reflect the light at middle wavelengths or around 510 nanometers, which is why it appears green to us.

But to see that green leaf, we have to use some complicated biological equipment. In the retina, a layer in the back of our eye, we have tiny structures called rods and cones. The rods enable us to see in dim light, and only show the world to us in black and white. The cones, which are less sensitive and require stronger light to work, are what enable us to see colors. We have three basic types of cones—red, green and blue. Those are the colors that each type of cone is most sensitive to, but each type actually can perceive a wider range of frequencies. The neural messages generated by those cones overlap and are stitched together by your brain, which enables you to see different gradations of color.

In recent years, neuroscientists have used brain scans to investigate where and how color is perceived by the brain. A study published in 2010 in The Open Neuroimaging Journal suggests that it may be a pretty complex process that takes place in several areas, including a region of the visual cortex known as the fusiform gyrus, or V4. Interestingly, researchers found that colored objects—whether natural or manmade—activated more areas than abstract colors or backgrounds, and that they recruited parts of the brain that are involved in information retrieval and spatial processing. That suggests that your brain utilizes colors to help recognize objects and pinpoint where they are located.

We don't all see colors exactly the same. While most of us can perceive about a million different gradations of color, there are rare individuals with cone deficiencies who see the world in black, white and variations of gray, and others who can't tell the difference between red and green, though they can perceive blue and yellow just fine. Eye diseases such as glaucoma and macular degeneration can also interfere with color perception. At the other end of the continuum, there are a few rare individuals called tetrachromats who have a fourth type of cone—orange, in addition to the usual red, blue and green—and can perceive as many as 100 million different colors.

Men and women also perceive color slightly differently, according to a study published in 2004 in American Journal of Human Genetics by evolutionary geneticists Brian Verrelli and Sarah Tishkoff. They found that women often have a genetic variation that enables them to discriminate between colors in the red-orange section of the visible spectrum more precisely than men. That ability may have come in handy in prehistoric times, when scientists believe that men hunted animals and women, who had to stay closer to the camp with the children, searched for berries and other plant foods.

A study presented in 2010 by University of Houston researcher Bhavin Sheth found that color perception actually drifts slightly in the course of a day, so that gray, for example, may eventually develop a faint greenish tint. After a good night's sleep, though, your brain apparently resets its color-perception equipment, and you see gray as gray again.

All in all, though, we seem to perceive pretty much the same basic color palette, even though the number of color-sensitive cones in the retina can vary by as much as a factor of 40, according to a study published in 2005 by University of Rochester researchers. A study published in PLOS One in 2013 by University of Liverpool perception researcher Sophie Wuerger found that the human ability to see colors remains constant over a lifetime, even as the cones lose sensitivity. All that suggests that our perception of color is controlled much more by our brains than by our eyes.

Shading the Truth—Why We See Colors That Aren't There

As we've learned in previous episodes of Brain Games, your brain continually faces a daunting task in perceiving and making sense of the immense flood of sensory information that you pick up from the world around you. To avoid overload, your grey matter has developed ingenious tricks and shortcuts—essentially, educated guesses based upon previous knowledge about the world that you've amassed in your life.

One of these tricks is color constancy. Once you get used to thinking of an object as a certain color—apples are red, bananas as yellow, and so on—you tend to perceive that object as being that color, even if it actually isn't.

When experimental subjects stare at a dot in the center of a color image on a TV screen, they'll continue to see the hues even after the image morphs into black-and-white. "We have millions of photoreceptors in our eyes that help us to see color," Yale University psychologist and perception researcher Scholl explains. "Now when you stare at the same color for a long time, the cells that are responsible for that color get tired and they don't respond as strongly. Then when the image flips back to black and white, those tired cells can't pull their weight and it's the cells for the complimentary colors that are more active. The result is that we experience a vivid sensation of color even when in this case the color's not really there."

How Colors Influence Us

This all is important, because color shapes our view of the world in myriad ways. But even after our ancestors stopped being hunter-gatherers and developed complex civilizations, color continued to play an important role in everyday existence. Scientists have discovered that different colors cause a variety of emotional responses—the short-wavelength color of blue, for example, has a calming effect, while longer wavelengths such as yellow, orange and red tend to make us more alert.

There's also evidence that colors may help to regulate our day-night cycles. A study published in 2012 in the journal Animal Behavior found that changing the color of light actually had a bigger impact upon the day-night behavior of fish than the intensity of the light. It may be that the atmospheric filtering that creates more yellow light in the morning has something to do with why we wake up then.

Colors' ability to trigger emotions may be why humans have long imbued them with symbolic meanings. In ancient Egypt, red and black were associated with death, while green signified life and yellow represented eternity. In Elizabethan England, the color of one's clothing was an indication of social class—only earls could wear purple silk or gold embroidery, while blue and crimson velvet were reserved for barons. In contemporary American politics, we divide the landscape into blue (Democratic) and red (Republican) states, with swing states denoted as purple.

But colors also seem to have a potent influence upon human behavior. A controversial study by English anthropologists, published in Nature in 2005, reported that in Olympic combative sports such as taekwondo and wrestling, athletes who wore red uniforms had a higher probability of winning the matches, suggesting the color may project a message of dominance that influences competitors. Another study by University of British Columbia researchers, published in 2009 in the journal Science, found that the colors on computer screens seemed to influence subjects' ability to perform various tasks. Groups with red backgrounds did better on tests of recall and attention to detail, such as remembering words or checking spelling and punctuation. Blue backgrounds, in comparison, seemed to help people to do better at imaginative tasks.

In the retail world, marketing experts carefully contemplate the effect of colors on consumer behavior. A study published in 2013 by University of Virginia associate professor of marketing Rajesh Bagchi, for example, revealed that in transactions with fixed prices, consumers were more likely to buy products when a store had blue décor than they were if the background was red. But at auctions, in contrast, bidders were more willing to pay after being exposed to a red background.

Color also influences how we think of other people. A study published in 2009 by psychologists at the University of St. Andrews in Scotland, for example, found that subjects used the color of another person's skin as an indicator of that person's health. A light-skinned person with a reddish flush to his or her cheeks was perceived as being fit and vigorous, while subjects judged a pale-looking person as being ill. There's actually something to this, because people who are physically fit, or else have high levels of sex hormones, tend to have more blood vessels in the skin, and thus become flush more easily.

Color and how our brains perceive it have a profound impact on our everyday lives, and we usually never even notice. Now that you're onto some of its tricks, you'll begin to see its influence all around you.

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Researchers have discovered a possible link between higher testosterone levels and what color?
  • Black
  • Blue
  • Brown
  • Red
Researchers have discovered a possible link between higher testosterone levels and the color...
  • Answer: Red
In Venice during the Renaissance, prostitutes were required to wear what color?
  • Red
  • Yellow
  • Black
  • Purple
In Venice during the Renaissance, prostitutes were required to wear...
  • Answer: Yellow
A rare condition that includes the ability to taste color is called what?
  • Aphasia
  • Synesthesia
  • Chromatosis
  • Schizoaffective disorder
A rare condition that includes the ability to taste color is called...
  • Answer: Synesthesia

How to Make Color Work For You

Four ways you can use color to your advantage.

In this episode, we learn how the colors that we perceive actually exist in our brains, which take the wavelengths of reflected light that our eyes observe and combine it with information from our past observations of the world.

But researchers also have discovered that just as our brains influence color, seeing certain colors can influence our brains in various ways. Here are some ways that you can use color to your benefit.

If you want to be trusted, be brown-eyed. (Okay, maybe you weren't born that way, but there are always brown-tinted contact lenses....) A study published in 2013 by researchers at Charles University in the Czech Republic found that research subjects who were shown photos of people rated brown-eyed people as more trustworthy than blue-eyed people, regardless of gender. That said, individuals with broad features were considered trustworthy regardless of eye color.

If you want to be more attractive to the opposite sex, wear red. A study by University of Rochester researchers, published in Journal of Experimental Psychology: General, found that women viewed men who wore red clothing as more attractive than those who wore blue. Additionally, women viewed red-clad men as higher in status, more likely to make money, and more likely to climb the social ladder. A study published in 2008 by one of the same researchers found that men feel more sexual attraction to women dressed in red as well.

Choose the background color for your computer screen, based upon the task you’re performing. A study published in 2009 by University of British Columbia researchers found that when subjects used a red background, they did better at tasks such as proofreading or solving anagrams, which requires attention to details. But a blue background seemed to produce better performance at creative tasks and intelligence tests, which require imaginative thinking instead of accuracy.

If you want to stick to your diet, choose your plate color carefully. An article published in the Winter 2011 issue of Cornell University Food and Brand Lab newsletter researchers presented findings that buffet diners who served themselves on a plate with a low contrast to the food color—pasta with red sauce on a red plate, for example—ate 22 percent more than those who served themselves food on plates that whose color contrasted with the food.

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