Optical illusions may seem like nothing more than visual trickery. But they are actually a result of our brains trying to predict the future.
When light hits our retina, it takes about one-tenth of a second for our brain to translate that signal into perception. Evolutionary neurobiologist Mark Changizi says this neural delay makes our brains generate images of what it thinks the world will look like in one-tenth of a second. It's not always right.
“Your brain is slow, so you need to basically create perceptions that correct for that delay,” said Changizi, director of human cognition at 2AI Labs.
Creating an image of the very near future probably kept early humans alive because it kept them from bumping into dangerous objects or being attacked by a fast-moving predator.
Click through the following images and see how our ability to predict the future one-tenth of second in advance also messes with your mind.
When images of objects flow across the retina, it activates all these different neurons in our brains. This is the mechanism by which the brain figures out how to extrapolate the next moment.
“When you move through the world, your eyes take snapshots,” said Chingazi. “During that snapshot, as something moves across your visual field, you don’t just end up with a dot on your retina, you end up with a blurred line on your retina.”
Our perception doesn’t see them, but the blurred lines make our brains realize that something is in motion. From there we can determine the direction of an object moving in our world. Since the blurred lines are all emanating from a single point in your visual field, they can inform you on the direction you’re going.
“Once you know the direction you’re going, you can determine how all these things would change in the next moment,” said Chingazi.
Take the above photo of “warp speed.” You don’t even have to question in what direction those blurred lines are taking you. Little did you know, "Blurred Lines" is more than just the most over-hyped song of the summer.
Perhaps the best representation of blurred lines and how they apply to optical illusions is the Hering illusion. Its radial spokes are blurred lines, all emanating from a single point. Those lines tell us where we are heading: forwards, towards the center.
The reason the two vertical lines appear to bow in the middle is because the radial lines suck our field of vision towards the center, as if we were in motion. In fact, those vertical lines are parallel, despite what our brain tells us. Our perception is actually showing us what those parallel lines look like in the next tenth of a second, the moment our gaze “passes through” the vertical lines, towards the vanishing point of the radial lines.
To simplify things, Chingazi suggests we imagine walking through a very tall doorway of a cathedral. When we’re really far away, the doorway sides seem parallel to one another. The angular distance between the top, middle and bottom of the door are all roughly the same.
“Once you’re really close or going through the cathedral doorway, the parts at eye-level are going to be wider apart,” he said. “When you look up, they actually converge like railroad tracks in the sky.”
Essentially, this is the same phenomenon that happens in the Hering illusion.
GRAND UNIFIED THEORY
Shapes aren’t the only objects that change as we move forward. Other factors like angular size -- how much of our visual field is taken up by an object – speed, distance and the color contrast between an object and its background also contribute to optical illusions.
Changizi determined that many illusions can be defined within his future-seeing process, so he created a chart with 28 categories that help organize what he calls his “grand unified theory.”
“This seven-by-four table really has one hypothesis that explains them all,” he said. “It makes a prediction across these 28 categories about what kind of illusions you should expect and how the illusions will reveal themselves across these 28 kinds of stimuli.”
The above illusion was created by a former student of Chingizi’s, and it demonstrates elements of speed, size and contrast. Move your head towards the center and the bright-white center appears to quickly fill the circle. Move your head backward and the dark perimeter appears to close in on the white center.
The orange circle on the left appears much smaller than the one on the right, when in fact they are the same size. This is the classic Ebbinghaus illusion, named after Hermann Ebbinghaus, the German psychologist who discovered it. British psychologist Edward Titchener popularized the illusion in the early 20th Century, as the illusion is also known as “Titchener circles.”
The juxtaposition of the circles’ sizes and distance from each other make them appear incongruent.
It’s time to play magician and make the pink splotches disappear. Stare at the cross in the center of the image and before you know it, you have a completely gray rectangle.
If we fixate on one single point, we tend to keep our eyes still. Those blurry pink orbs are now on the periphery of our visual field and tend to disappear because we’re zeroing in on the cross. Despite being physically present, the pink smudges do not stimulate our neurons enough to maintain visual perception. The phenomenon is known as “Troxler’s fading,” discovered by Swiss physician Ignaz Paul Vital Troxler in 1804.
Although the pink dots are static, they’re actually a part of an animated illusion called the “Lilac Chaser,” created by Jeremy Hinton around 2005. In that illusion, a green dot seemingly “eats” the other dots in a clock-wise fashion, thus it’s sometimes known as the “Pac-Man” illusion.
CAFE WALL ILLUSION
This illusion is attributed to British psychologist Richard Gregory. Legend has it that his lab assistant saw this illusion in the wall tiles at a cafe in Bristol. The black and white pattern was offset by a half a tile, causing the illusion to appear.
Though they appear to be at an angular pitch, the horizontal lines are parallel. Distance and contrast are two operating variables in this illusion.
Interested in seeing the tiles at the original Bristol location? The cafe is still there, but it’s reportedly closed. However, curious trekkers can find it at the bottom of St. Michael's Hill.
Akiyoshi Kitaoka, Cmglee
So-called peripheral drift illusions, such as Japanese psychology professor Akiyoshi Kitaoka's “Rotating Snakes,” are motion illusions that occur in our visual periphery. These illusions work best when you look off to the side of the image.
Earlier studies of the “Rotating Snakes” suggested that perceived motion was triggered by eyes moving slowly across the images. But a 2012 study, led by neuroscientist Susana Martinez-Conde, showed that fast eye movement, some of which is microscopic, drive the perceived motion.
Antonio Miguel de Campos
The scintillating grid is an illusion created by superimposing white dots at the intersection of gray lines on a black background. Dark dots seem to appear and disappear at the intersections, and jump around the grid, thus the term “scintillating.”
Trying to pin down one of the black dots with your gaze is like playing a hands-free version of Wack-a-Mole, as the dark spots only appear in your periphery.
One of the clearest examples of how sharp, black-and-white contrast effects the gray scale can be seen in the image above.
The gray bars between the black stripes appear darker than the gray bars between the white strips. However, the gray bars are the same shade. Chingizi’s “grand unified theory” states the higher the contrasts nearby an object, the lower in contrast that object will appear.
3-D CHALK DRAWINGS
Lady, look out for that giant snail, it’s about to attack! Oh wait, shwoo, it’s only one of Julian Beever’s pavement drawings.
The English artist and renowned darling of gotta-see Internet pics has been taking to streets and sidewalks all across the world since the mid 1990’s. He employs a projection technique called anamorphosis to give the illusion that his drawings are three dimensional when viewed from a certain angle.
Idea Generation / Barcroft Media /Barcoft Media via Getty Images
3-D CHALK DRAWINGS, AGAIN
Shoppers in Camberley, England, got a glimpse of Santa in his snowy underground grotto courtesy of Julian Beever's amazing 3-D street art.
While this image looks like a model of the future’s coolest water slide, it’s artist Anh Pham’s version of a peripheral drift illusion.
Concentrate on one of the pink spots and you may be able to stop that ring from moving, but it’s a different story in your visual periphery. Good luck tearing yourself away from this one.
Go to any tourist destination in the world that has an iconic structure, such as the Eiffle Tour, the Taj Mahal or the Washington Monument, and you’ll find tons of fanny-packed shutter bugs creating their own optical illusions. Because objects in the distance appear smaller, altering your perception angle can make it seem like the Eiffle Tour is small enough to fit in the palm of your hand. Or that you can push against the Leaning Tower of Pisa to keep it from falling over.
As the above couple demonstrates with the incredible-shrinking-man illusion, altering your perspective can drastically change your perception.
- There may be certain areas in the brain that are enlarged or extra efficient that could lend some language learners an advantage.
- Studies show that it becomes more difficult to learn new languages as you get older.
- Neuroscientists are still trying to understand all the various brain regions involved in learning language.
In his spare time, an otherwise ordinary 16-year old boy from New York taught himself Hebrew, Arabic, Russian, Swahili, and a dozen other languages, the New York Times reported last week.
And even though it's not entirely clear how close to fluent Timothy Doner is in any of his studied languages, the high school sophomore -- along with other polyglots like him -- are certainly different from most Americans, who speak one or maybe two languages.
That raises the question: Is there something unique about certain brains, which allows some people to speak and understand so many more languages than the rest of us?
The answer, experts say, seems to be yes, no and it's complicated. For some people, genes may prime the brain to be good at language learning, according to some new research. And studies are just starting to pinpoint a few brain regions that are extra-large or extra-efficient in people who excel at languages.
For others, though, it's more a matter of being determined and motivated enough to put in the hours and hard work necessary to learn new ways of communicating.
"Kids do well in what they like," said Michael Paradis, a neurolinguist at McGill University in Montreal, who compared language learning to piano, sports or anything else that requires discipline. "Kids who love math do well in math. He loves languages and is doing well in languages."
"This is just an extreme case of a general principle," he added. "If you practice and have a great deal of motivation for a particular domain, you're going to be able to improve in that domain beyond normal limits."
Very young children are remarkably good at learning multiple languages simultaneously. They can develop native-sounding accents in each tongue. And into adulthood, all reinforced languages hold their own in the brain without interfering with the others -- unlike later learners who may have trouble remembering a second language when they begin to learn a third.
With age, though, it not only becomes tougher to learn new languages, there may even be developmental stages beyond which certain nuances of language simply become inaccessible. By the age of 9 to 12 months, for example, babies begin to lose the ability to distinguish between sounds that are not used in their native language, said Loraine Obler, a neurolinguist at the CUNY Graduate Center in New York.
Some brains may be better than others at learning languages.iStockPhoto
After about age 4, most people will never gain a truly deep grasp on a second language's morphology, which refers to the rules that govern how words are formed from linguistic units. After age 7 or so, the brain begins to pay more attention to what it's learning, Paradis said, which affects the type of memory kids use to pick up languages.
And beyond puberty, it becomes unlikely that someone will be able to speak a new language without a foreign accent, though Doner is unique in how impressive his accent sounds, which may reflect a late-to-mature brain. (There seems to be no cut-off point for learning vocabulary).
For more than a century, scientists have known that there are key areas on the exterior cortex of the brain's left hemisphere, known as Broca's area and Wernicke's area, that are critical for learning to speak and understanding speech, Obler said. There are also many other areas throughout the brain that process language.
Genes, neurotransmitters and brain regions involved in long-term memory play roles as well, Paradis said. And a number of different structures probably come into play when people speak a second language compared to when they speak their first.
That would explain why brain damage from Parkinson's, Alzheimer's or other disorders that affect specific areas of the brain can knock out just a native language -- or just a language that was learned later in life, leaving the other one intact. Aging can also bring out an accent that was once unnoticeable.
Only in the last few years have scientists begun to zero in on brain regions that seem to matter most in helping polyglots develop their impressive skills.
In a 2008 study in the journal Cerebral Cortex, for example, researchers found better language learning abilities in college students with a larger Heschl's gyrus, an area on the left side of the brain that processes pitch. But that finding only applies to learning tonal languages like Mandarin, said study author Patrick Wong, a neuroscientist at Northwestern University in Evanston, Illinois.
In another study, published last year in the Journal of Neuroscience, Wong's group found that good language learners had stronger connectivity in the white matter of the auditory cortex, which is part of the language network. And in studies currently in press, the team will announce better efficiency in connections between neurons as well as a genetic component to the whole system.
And it's not just polyglots who are providing clues, Obler added. In her research on people who struggle with new languages, she has found parallels with dyslexia.
Yet, even as research reveals biological clues in the brains of polyglots or their opposites, we are probably not completely fated to either excel or fail at languages. Our biology may simply determine which strategy we should use to learn new dialects.
"You're not doomed just because your Heschl's gyrus is small," Wong said. "The goal in our research program is to find predictors. And once we find predictors, we can put people into the right kind of training program."
But the field of neurolinguistics is still new. So for now, the process of language learning in the brain remains full of secrets.
As Obler said, someone once "wanted to know how to make the brains of merely normal learners as good as excellent learners. I said, 'I'm not going to be able to answer that for decades.'"