Ever look at a picture, photo, or even a wall and feel as if you were being tricked? Maybe you rub your eyes a little, or scratch you’re head a couple of times, close one eye. keep the other one open, etc. You may think you’re going mad, or maybe you took the wrong pill from the medicine cabinet. If you have ever experienced this but did not understand what was happening, then you probably ran into what’s called an optical illusion.
An optical illusion is an illusion caused by the visual system and characterized by a visual perception that differs from reality. They can be illustrated by artists, doctors, or even architects. Optical illusions can be both fun and practical. They have been used to check eyesight or give a physiological prognosis, and they can also be used for a good time with the kids. Or they can even serve as a good poster to hang in your bedroom.
We’ve gathered 40 of our favorites for you to look at. Enjoy!
What kind of sorcery is this?! This is known as the silhouette illusion; it’s a kinetic, and bi-stable optical illusion that resembles a twirling female dancer. It was originally distributed as a GIF animation, created in 2003 by Japanese web designer Nobuyuki Kayahara. Some people initially see the figure as spinning clockwise, but others see it as counterclockwise.
The direction of the turn is still disputed to this day, so I guess it’s up to you to decide! To get technical, the illusion comes from the lack of visual cues for depth. Like as the dancer’s arms move from your left to right, it’s possible to see her arms passing between the body and the viewer.
What you are looking at here is called the “roller” optical illusion. Like some of the others on this list, it was invented by Japanese professor Akiyoshi Kitaoka. The image was created through scientific research and technology. But let’s be honest, they are also enjoyed as works of art. If you stare at any point within the image, it will seem like there is a second dimension where the circles are rolling in and out.
Fun fact: optical illusions are dated back to the 5th century – a time when the surroundings were still known to be a mystery and people were just waiting for it to be solved. Optical illusions were one of the topics that existed then. Greek philosopher Epicharmus was the first to provide the answer to it. He explained how sensory organs are mainly responsible for the deception, and cause us to see more than the reality.
The Hering Illusion
The Hering illusion is a geometrical-optical illusion that was discovered by the German physiologist Ewald Hering in 1861. Two straight and parallel lines are presented in front of a radial background, just like the spokes of a bicycle. The lines appear as if they bow outwards. At first glance, you may think the red lines are bending, but they are actually two straight lines.
Researcher Mark Changizi explained it in a 2008 article: “Evolution has seen to it that geometric drawings like this elicit in us premonitions of the near future. The converging lines toward a vanishing point (the spokes) are cues that trick our brains into thinking we are moving forward as we would in the real world, where the door frame (a pair of vertical lines) seems to bow out as we move through it and we try to perceive what that world will look like in the next instant.”
The Famous Ebbinghaus Illusion
This is an illusion that deceives our size perception. You can’t tell right away, but both orange circles in the image are actually the same size. This is due to our perception that the proportions in conjunction with the surrounding circles are different. So, at first glance, the circle on the left looks smaller, and on the right, it looks bigger.
This illusion is used extensively in research in cognitive psychology, where researchers want to find out more about the various perception pathways in our brain.
Hermann Ebbinghaus, born in 1850, was a German psychologist who pioneered an experimental study of memory, and he’s known for his discovery of the “forgetting curve” and the “spacing effect.” He also was the first person to describe the “learning curve.”
What you are looking at now is a periphery illusion. If you look at the image directly while keeping your eyes still, you will see nothing. But once you take your eyes off the center and let them travel around the screen, you will see that the squares seem to be spinning. Hopefully, it doesn’t give you a headache!
As we go about our lives, we operate under the assumption that our perception directly and accurately represents the outside world. But according to psychology researcher Marte Otten from the University of Amsterdam, “Under the right circumstances, a large part of the periphery may become a visual illusion. This effect seems to hold for many basic visual features, indicating that this ‘filling in’ is a general, and fundamental, perceptual mechanism.”
The image has a checkerboard with light and dark squares, which is partly shadowed by another object. The illusion is that the area labeled A looks to be a darker color than the area called B. However, within the two-dimensional image, they look as though they have identical brightness, i.e., they would be printed with the same mixtures of ink, or displayed on a screen with identical pixel colors.
The Adelson’s checker shadow illusion was published by Edward H. Adelson, a professor of Vision Science at MIT, in 1995. And really, although it literally is the same color, I personally am not convinced! Do you see the same or different colors? This is one of the more baffling ones.
The Gray Bar
The picture here shows a better example of the same kind of premise as the checkerboard illusion. Believe it or not, the gray bar in the middle is exactly the same shade of gray from end to end. I know, it almost feels like the world is playing a trick on us, right? But the truth is the light to dark contrast behind it is what makes it seem as if it gets lighter on the right.
This optical illusion is known as the Bezold effect and was named after a German professor of meteorology, Wilhelm von Bezold (born in 1837). He discovered that a color will appear different depending on its relation to adjacent colors.
What you see in front of you is the “Rabbit-Duck Head” illusion; an ambiguous image where a rabbit or a duck can be seen. The earliest known version of this illusion is an unattributed drawing from October 23, 1892, in an issue of Fliegende Blätter, a German humor magazine. In those days, hidden images were very popular.
It was captioned “Welche Thiere gleichen einander am meisten?” (Which translates to “Which animals are most like each other?”) After this was used by psychologist Joseph Jastrow, the image was then made famous by Ludwig Wittgenstein, who used it in his Philosophical Investigations as a way to describe two different ways of seeing: “seeing that” versus “seeing as.”
The Shepard Elephant
When you first look at this image, nothing is suspicious, and it just looks like a typical elephant illustration. The artist has gone further though and confuses the mind by making it look like there is either one leg missing, or too many legs altogether. Can you count how many you see? Or is your brain hurting?
Shepard published this optical paradox in his 1990 book called Mind Sights (on page 79) giving it the name “L’egs-istential Quandary.” The illusion is the first entry in his chapter on “Figure-ground impossibilities.” The drawing is based on a dream he had in 1974 and the pencil sketch he did when he woke up.
Are You Sober?
This is an optical illusion you may want to avoid unless you are 100% sober! It’s called the “motion illusion,” and it’s among the most common optical illusions in existence. It’s impossible to stare at contrasting illustrations such as this without seeing the objects on them move.
The term “illusory motion,” which is also known as motion illusion, is an optical illusion that involves a static image that appears to be moving. It’s due to the cognitive effects of a few things: interacting color contrasts, object shapes, and position. The most common type of motion illusion is Apparent motion and is happens when images are displayed in a series at a specific frame rate like in a movie.
This one is called the double drawing illusion and there are many versions of it out there. In this particular one, the most famous version, there are various faces all lumped into one. This illusion is handed out in worksheets in many kindergarten books. Keep your eye out for it; if your kid didn’t take it home from school, it’s still a great activity to do during dinner.
Illustrator W.E. Hill created the cartoon of an old and young woman in the same frame. He merged the two faces into and some believe that it’s a picture of an old woman while others see only the young woman. I can see both. Can you?
This is another very well-done motion illusion that will sure to make you busy (or sick). Nothing deceives the eye more than pictures such as this. I personally felt sick to my stomach looking at it, and quickly moved on to the next one! But let’s see if you can manage more than a millisecond looking at this thing!
Optical illusions reveal the way our visual system edits images before we even are made aware of them – kind of like a personal assistant, telling you what is and isn’t worthy of your attention. People created optical illusions long before any of us knew what made them work. These days, advances in neuroscience pinpoint the visual processes that fool our brains into falling for many of them.
This optical illusion is called “The Roundabout.” Stare at the white circle in the middle, and you will start to see all the colors begin to swirl around in different directions. Pretty trippy if you ask me!
The cognitive processes hypothesis states that visual illusions happen because the neural circuitry in our visual system evolves and it does so by neural learning. It evolves into a system that makes very efficient interpretations of 3D scenes “based in the emergence of simplified models in our brain that speed up the interpretation process but give rise to optical illusions in unusual situations.” I mean, if you really wanna get technical.
This photo uses visual vibrations that create a cooling effect. If you move your head close to the screen, and then away from it, the fuzzy dots will appear to move. Perceiving optical illusions is controlled by our brains. The brain can easily switch between two different views of something – from two-dimensional on a piece of paper to an object that we think is 3-D. But how?
The 1981 Nobel Prize in Physiology or Medicine was awarded to David Hubel and Torsten Wiesel for their discoveries in how brains interpret the coded communications sent to it from our eyes. They discovered that there is a stepwise process in how our brains analyze what the eye sees. Each nerve cell in the brain is responsible for one detail in the pattern of the retinal image.
My Wife and My Mother
This illustration is very similar to the one further up, but it’s just as popular. This one has people scratching their heads since 1915. This illustration, made by British cartoonist William Ely Hill, is a facial perception trick. If you look at the image, you either see the face of the “Wife” or the face of the “Mother in Law,” but never both.
And the thing is, once you see the old lady or the young woman, it’s really hard to unsee it. But either way, it’s impossible to see both faces at the same exact time. Our brains just can’t handle all that information. Talk about information overload!
This street art in a New York subway walkway seems to show a set of stairs that lead to nowhere. At first glance, it appears to block your way, right? I wonder if people ever try to move around it. I’m sure they have. If I saw it, I would certainly stare at it and to others around me, I would appear to be on something.
Fun fact: Optical illusions are everywhere. Aristotle himself noticed optical illusions in waterfalls. Our friend Indiana Jones saw one in rocks when he made his leap of faith across that giant crevasse in the “Indiana Jones and the Last Crusade.” We see them everywhere – from M.C. Escher drawings to internet memes (was that dress blue or gold?).
Concentrate on the four dots in the middle of the picture for about 30 seconds. Then close your eyes and tilt your head back. Keep them closed, you will see a circle of light, continue looking at the circle… what do you see? If you see a picture of Jesus, then you’re like everyone else.
Once we’ve seen the “trick” of an illusion, it’s almost impossible to un-see it. We can’t just transport our minds back to the point when we didn’t know this thing that we just learned. Once the knowledge is available, our brain accesses it quickly and puts it together with all the visual cues that you got from actually looking at the illusion.
There are many variations of this type of optical illusion, but you will always see the same result. That is, the two colors that seem to be different are actually the same color. In this case, it’s the blue and green. If you don’t believe it, you verify it on PhotoShop yourself. It’s okay, I’ll wait…
Optical illusions aren’t just a function of our eyes and brains. Our perception may also mostly be influenced by cultural factors. The biological basis for how optical illusions work is universal across humans, but when some illusions are seen by people in different cultures, not everyone sees the same thing or even missed the same visual cues.
Two Shades of Grey
You might have already seen this one before – it’s one of the more popular ones. But it’s another headache-causer (for me at least). The standard two shades of grey here may start to move pretty actively. All you have to do is stare down the photo in the middle. This one makes me dizzy, so I’ll move on.
In one study on cultural differences in viewing optical illusions, most European South Africans thought the lines of one illusion were of different lengths. But bushmen in certain South African tribes correctly noted how they were the same lengths. Scientists theorize that people in western societies are simply used to seeing straight lines and geometric shapes. People from other cultures aren’t exposed to the same geometric configurations
Stare at the center of this fuzzy image above and try not to blink. After a few seconds, what do you see? Do you see the image starting to fade away? This type of visual phenomenon is called the Troxler Effect, which was first discovered by Swiss physician Ignaz Paul Vital Troxler back in 1804. It reveals how our visual system adapts to sensory stimuli.
Our neurons stop responding to unchanging stimuli. In this case, the blurry image in the background causes the image to disappear from our consciousness. It’s a mind-bending optical illusion. These photos give us a scientific view into the complexity of the human brain, and are also very fun to look at too!
The Impossible Trident
Look at it closely. The three prongs transform into two at the end of the fork. And the more you look at the image, the more improbable it becomes. What’s going on? People have often said that this made its debut on the cover of “Mad Magazine” their March 1965 issue.
The original graphic art, the impossible trident, is also known as the Devil’s Fork, the Impossible Fork, or a blivet. The lines join at the end to create the illusion of a prong. And since our minds tend to reconstruct 3D images out of a flat 2D image, it creates the illusion of depth. For me, I can’t not see the middle prong.
This is a physiological trick first and foremost. Our mind has two reactions to this photo, around the monsters the dimension seems to bend and signify a never-ending corridor, which ignites a bit of fear. The two senses in our mind will then make us think that these two monsters are different sizes with the small one running away from the big one.
But if you take a piece of paper, and draw a dot from head to toe on the big monster and then move those same two points to the small monster, you’ll see that these two monsters are indeed the same size. Blown away? Yeah, our minds are pretty cool, huh?
Check if You’re Blind
This recently discovered perception trick has people questioning how we see the world around us. Look at the lines in the image. What kind of lines do you see? Straight, edgy zigzags, or soft, curvy waves? Do you see one kind or both?
This optical illusion was discovered by an experimental psychologist named Kohske Takahashi from Japan’s Chukyo University in 2017. It’s called the “curvature blindness illusion,” and it’s the latest example of how we just can’t always trust our eyes when we’re looking directly at something. You probably see both wavy and zigzag lines in alternating pairs. That is, if you’re staring at the lines in front of the grey background. Each background yields different results.
The Classic Penrose Staircase
There is a big chance you have already come across this optical illusion once or twice in your life. It’s called the Penrose Staircase. This photo has a two-dimensional staircase with four 90-degree angles thus forming a continuous loop. It’s nicknamed the “impossible staircase” and has been featured in the movie “Inception.”
The paradox can only be achieved in the dream worlds in the film. In the movie, the hero goes down the stairs, fleeing from a guard. But in the real world, the hero should really always be in front of the villain throughout such a chase. However, with the Penrose stairs, the hero descends another flight to catch up to the villain and catch him off guard.
The Ponzo Scheme
In this Ponzo illusion, two identically-sized lines seem to be different sizes when they’re placed over parallel lines that look like they converge as they recede into the distance. In the image, the two lines are the exact same size. Since they’re placed over parallel lines that appear to converge in the distance, the top line appears to be longer than the bottom one.
This illusion was first demonstrated in 1913 by Italian psychologist Mario Ponzo. The reason the top line looks longer is because we interpret the scene using linear perspective. Considering how the vertical parallel lines seem to come closer as they move further away, we see the top line as being further in the distance.
The Necker Cube
The Necker Cube was named after its creator, Louis Albert Necker (born 1786), who published this illusion in the London and Edinburgh Philosophical Magazine and Journal of Science in 1882. The cube belongs to a large class of illusions involving a 2-D figure, or 3-D object can be seen in two or more distinct ways.
There are many example of such figures. One reason the Necker Cube is interesting is that although you can see the image as one of two cubes differently, it’s possible to see it as simply 2-D. Therefore, the Necker Cube is ambiguous. There is controversy over how the cube works and had been debated for years.
This is yet another movement, color, and dimension illusion that will have you staring at it for a long time. I can’t tell if I’m looking at fish or snakes. But whatever it is, I like the calm, gentle movement. This one happens to be a much more relaxing optical illusion than the other ones on this list.
While some of the others made me nearly physically sick, this one is oddly soothing. It’s pretty amazing how the brain processes images like these. Like, I am fully aware that this is a static image, but my eyes are seeing those things moving! Doesn’t matter how many scientific explanations I can find, these fishies are moving before my eyes!
Stay on the Grid
This grid is similar to the well-known Hermman grid illusion, where grey dots appear at the intersections of a white grid on a black background. But this Scintillating grid illusion goes a step further, with white dots at the intersection of a gray grid on a black background.
When you look at the grid, black dots pop up at the intersections, creating a “scintillating” effect. This is called a simultaneous light contrast illusion. The white dots are perceived many times as white, and at other moments as black. Interestingly, this kind of illusion is created only when your eyes are not staring at a fixed point. If you are too close or far from the image, those dark dots disappear.
The Impossible Triangle
Here’s another version of the Penrose stairs, but this one is called the Penrose triangle, or the Impossible Tribar. It’s a triangular impossible object, which is an optical illusion that consists of an object which can be seen in a perspective drawing but can’t exist as a solid object. It was created by Swedish artist Oscar Reutersvärd in 1934.
Unrelated to Reutersvärd, the triangle was popularized in the 1950s by psychiatrist Lionel Penrose and his son. Roger Penrose is a mathematician who described the illusion as “impossibility in its purest form.” You can see it prominently in the works of artist M. C. Escher. Escher’s early depictions of impossible objects were said to have inspired the impossible tribar.
If you look at this picture closely, your eyes will most likely be fooled for at least 10 seconds. No, this is not two cuts of wood, but actually one whole piece! It’s the slight lining in the middle of the block with the dimensions of the nails making it look like two.
This object and others on this list can be categorized under the category of impossible objects. An impossible object (aka an impossible figure or an undecidable figure) is just one type of optical illusion. It consists of a 2-D figure which is instantly and subconsciously interpreted as a 3-D object. In most cases, the impossibility is apparent after looking at the figure for a few seconds.
And yet another photo of an optical illusion made from different colors, shapes, and dimensions! In case you missed them, I clicked right onto the next one because it moved fast and made me completely sick! If you have a weak stomach, I suggest you do the same! If not, then I think the illusion here is pretty clear. The lines appear to be crooked and moving, when in fact, they’re not. Surprise!
Back to impossible objects – what’s strange is that the initial impression of a 3-D object remains, even after it’s been contradicted. There are more subtle examples of such objects where the impossibility doesn’t become apparent spontaneously and you have to consciously examine the geometry of the object to determine that it’s impossible.
More Valentines Ideas
If you’re trying to come up with a new and interesting and also strange idea for a Valentine’s card, I can make a suggestion. Maybe give your sweetheart a copy of this image. First, though, try and see if the heart is behind the lines in front of them. Then you can ask your lover to do the same.
And if they get dizzy just looking at it, you can say that’s the way you feel when you look at him/her because you’re so in love. How cheesy! But it’s okay, Valentine’s Day is the one day of the year that you have full permission to be as cheesy as you want.
Most people don’t even come close to finding them right away, but there are actually 16 circles inside this picture to look for! This is called the Coffer Illusion. It was actually a finalist in the 2006 Best Illusion of the Year Contest. The Coffer Illusion initially looks like a series of sunken rectangular door panels, but after a moment, your brain’s representation of the image can “flip” to make it look like there are 16 circles.
People have been fascinated by these kinds of figures since the time of the ancient Romans. The Coffer Illusion deals with the fact that the visual brain is meant to identify objects. “Pixels” are grouped and form edges and contours, shapes, and then objects.
Worst way To Start Your Day
If you’re planning on buying a mug for someone that will help them start the day off with good energy, don’t buy them this grid mug! It’s sure to make them even dizzier than they were when they woke up! And don’t even get me started on what looking at this mug would be like when you’re hungover.
But on the other hand, if you don’t have a weak stomach and don’t tend to be hungover, then this kind of mug is pretty cool. I mean, it’s one of those mugs that you can just stare at between 6:45 and 7:04 in the morning, as your brain is trying to process things before you start your day.
No, it’s Not the Grappa
Speaking of being hungover, no, feeling like you’re falling over is not because you had too much to drink. What you are looking at here is two identical images of the Leaning Tower of Pisa in Rome. The one on the right seems more lopsided because the human brain is only capable of treating the two images as one scene.
So even if both towers in this image are actually straight, side by side you will not be able to see that. This image won the 2007 Visual Illusion of the Year Contest.
Fun fact: the tower started to lean during its construction in the 12th century. It was due to the soft ground which couldn’t properly support the structure’s weight. It got worsene through the completion of the tower in the 14th century. By 1990, the tilt reached 5.5 degrees
Remember the Valentine’s Day idea from a few pages up? You know, the really cheesy one. Well, if you wanted something similar, you can use this one. If you want to catch someone’s attention on the day of love, these hearts will do the trick. Write your valentine a card with this picture on the front with some instructions to stare and watch the hearts move around in gentle motion.
Fun fact: The history of Valentine’s Day (and the story of its saint) is shrouded in mystery. The Catholic Church recognizes three different saints (at least) named Valentine or Valentinus. All of them were martyred. One legend holds that Valentine was a priest who served during the 3rd century in Rome.