It's extremely easy to trick our brains — and we are oddly delighted by it. But there's also a practical side to illusions, learning about where the brain gets confused can help us understand how it works to organize information in the first place.

Sometimes, a few splashes of color arranged in a very specific way can scream "mistake" to the brain. In response, brain cells will begin to fire to "correct" our vision … and the scene will disappear. Other times, an image that looks like a duck can look like a rabbit if you really try to see it. But the brain won't let you see both the rabbit and the duck at the exact same time, you have to tell it a story first. And it's not only vision that tricks us — the same recording of a word can sound like "Yanny" to some people and "Laurel" to others. What you see or hear, is not always what's happening.

Here are some of Live Science's favorite illusions from 2018.

This illusion might not help you go back and un-spill your coffee all over a stranger, but it will bring you back in time — if only for a second. The video demonstrates a concept known as "postdiction" (like "prediction," but after, not before) , the idea that watching a new stimulus can change a person's perception of a stimulus that happened a mere split-second prior.

To see the illusion in action, watch the video with sound and count the number of flashes you see. 

In reality, there are two flashes. But the first time around, there are three beeps, with one sounding off in the middle of the two flashes, so the brain uses "postdiction" to fill in an extra flash in between the two real ones, thinking that you must have simply missed it. It also shows how sound and vision can be intertwined and throw each other off, if only to joke around.

[Read more about these flashes and beeps]

 
 
 
 
 
 
 
 
 
 
 
 
 

Right Pointing Arrow: spin this arrow 180 degrees and it still points to the right- only in a mirror will it point left (and only to the left). Another incredible ambiguous object illusion by mathematician Kokichi Sugihara of Meiji University in Japan, the inventor of this illusion and art form. A clever combination of reflection, perspective, and viewing angle produce this striking illusion. Follow the link in my profile for info about where to get this illusion arrow and other amazing items featured here on @physicsfun #illusion #ambiguouscylinderillusion #ambiguouscylinder #geometry #mirrorreflection #physics #ambiguousobject #kokichisugihara #physicstoy #math #mathtoy #mathstoy #optics #opticalillusion #3dprinting #perspective #science #scienceisawesome

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The arrow points right. The person rotates it 180 degrees. The arrow still points right. The person rotates it 180 degrees. The arrow points right.

This is an optical illusion designed by mathematician Kokichi Sugihara — and it's maddening. The brain has a thing for finding right angles, even when there aren't any. Basically, your brain is seeing curves but pretending they are right angles. This phenomenon is referred to as the "ambiguous cylinder illusion" in which the brain tries to create order out of chaos, but in doing so, it makes you see something completely different than what's in front of you.

[Read more about this maddening arrow]

This picture will fade away if you stare at it (may take a minute) from r/woahdude

Stare at this illusion too look and it'll disappear To try it, pick a spot to focus on, and the pastel colors will fade away. The illusion illustrates what researchers call the "Troxler Effect." It's thought to occur because the brain is trying to be efficient and is really good at adapting to new stimuli. Indeed, the brain does this every day — it helps you ignore the feeling of the ring on your hand, the drone of the air conditioning and the smell of the office. The brain helps you not get overwhelmed by unchanging stimuli so you can focus on other things. 

Ignaz Paul Vital Troxler, a Swiss physician and polymath, first discovered this effect. He found that when a person stares at a specific, unchanging spot for a long period, details in their peripheral vision begin to fade. If those details are blurry or low contrast like these pastels are, they fade faster.

[Read more about these disappearing colors]

What do you see when you look at this image by artist Joseph Jastrow, published in 1899 in Popular Science Monthly?
What do you see when you look at this image by artist Joseph Jastrow, published in 1899 in Popular Science Monthly?
Credit: Fine Art Images/Heritage Images/Getty

Do you see a duck or a rabbit? This image shows how the same thing can be seen in two different ways — but also warns you about seeing something as you want to see it. Let's say, at first glance,you can see the duck. Then, someone shows you the rabbit, and now, you can see the rabbit. But you probably can't see both animals at the same time. This is even more difficult to do when you place a copy of the image next to the first — you will most likely see either two rabbits or two ducks.

But there is a way to see both animals at once, by creating a story in your brain (in other words, contextualizing it). For example, "the duck is eating a rabbit." If you add context, the brain can zoom out of the details and see the bigger picture — and the story. But phrases such as "imagine a duck beside a rabbit" wouldn't work because your brain doesn't know which is the duck and which the rabbit.

[Read more about the duck and the rabbit]

That yellow text that disappears into a black background far, far away is an iconic feature the "Star Wars" movies — and something that can also easily be transformed into an optical illusion. If the yellow  text is duplicated and placed right next to the original, in the exact same orientation, people will start to see one moving toward the left side of the screen and one toward the right, even though it's the exact same text, moving in the exact same direction. This is known as the "Star Wars scroll illusion," which  was first explored by Arthur Shapiro, a visual illusions expert and professor at American University. A non-moving version of this illusion, called "The Leaning Tower Illusion," was previously studied — if you place two identical pictures of the Leaning Tower of Pisa side by side, they look like they're leaning in different directions.

The trick has to do with the way your brain perceives the vanishing points in the screen, or where the texts, or towers, disappear to. For a reason unknown, when these two identical scrolls of text are placed side by side, the brain sees the vanishing points in different spots than where they actually are. 

[Read more about the Star Wars scroll illusion]

2018 wasn't just a year for optical illusions — there was also an auditory illusion that swept the internet in May of this year. Enter Yanny and Laurel. 

Why did these two words tear people apart? Yanny and Laurel both have the same timing and energy content as words, so they're easily interchangeable, experts said. In fact, there's no "true" word — in other words, no right answer —  but instead, a set of frequencies for your brain to interpret. One idea is that the brain picks a word and convinces itself that it's the correct interpretation, so that's what you hear. In addition, your past experiences and expectations can shape whether you hear Yanny or Laurel. So can your age, your ear shape and even your speakers.

[Read more about Yanny and Laurel]

"My Wife and My Mother-in-Law" is a famous optical illusion that depicts both an old woman looking off to the left and a young woman facing away, looking over her right shoulder. (The old woman's nose is the young woman's chin.)
"My Wife and My Mother-in-Law" is a famous optical illusion that depicts both an old woman looking off to the left and a young woman facing away, looking over her right shoulder. (The old woman's nose is the young woman's chin.)
Credit: public domain

"My Wife and My Mother-in-Law" is an illusion that first appeared on a German postcard at the end of the 19th century. The image shows two. There are two ladies in the image, a young woman with her head turned over her shoulder and an old woman looking straight ahead. But which woman you see initially could depend on how old you are, according to a study published this year.A new study this year found that how old you are could influence who you see first. Using thean online crowd-sourcing platform called Amazon's Mechanical Turk, researchers found that younger people tended to see the younger woman, whereas the older population saw the older woman. The researchers also asked the participants to estimate the age of the woman. The younger the participant was, the younger they said the woman was. The reason could be due to an "own-age-bias," which means we process faces from ages similar to our own more thoroughly than faces of other ages, or it could be due to sociocultural practices of being less inclusive to the elderly, according to the paper. 

[Read more about this ageless woman]