Mind-Blowing Optical Illusions

It might seem to be a weird way to start an article, but please take a look at this lady in the image below. Focus on the red dot on her nose for 10 seconds, don’t look away, and don’t blink!

Then, shift your gaze to a blank screen or wall and you'll see that lady clear as day in natural colors, which means, you've seen something that you actually didn’t see! That's very cool, but how does it work? Let's take a look at some amazing optical illusions, and discover how they work!

Pareidolia

Do you see human faces in things with random patterns? Like in coffee, tree stump, or old walls? Some people claim they can even see a face in the moon! We see faces in everything, so with that in mind, can you see what’s hidden in the image below?

You might spot a face under that ear! Our tendency to find patterns like this in abstract places is called pareidolia. More often than not, we see faces where there aren’t real faces because humans are super-attuned to seek out faces, it’s part of our social psychology.

And using this to make optical illusions dates all the way back to 1880, so we’ve known about the phenomenon a long time! Here’s another variant with a bear, see if you can spot the face:

Did you get it? It's between the bear's lower jaw and the ear. Let’s put your pareidolia to the test. How many faces do you see in this tree?

How many did you get? 6? 7? There’s actually 10.

Corrective Pareidolia

Look at this picture of a face flipped upside-down.

While it might not seem out of the ordinary at first, look closer. Let’s flip it over to the correct orientation, and how did that ever look normal upside down?

The image has been edited in a pretty simple way; the eyes and mouth have been flipped around. As it turns out, our minds are so hardwired to recognize and read faces that, when we’re presented with one that doesn’t quite work, our brains tend to correct the image to make sense of it. As the eyes and mouth are so expressive, if they’re readable, we can imagine the rest easily.

It’s believed we do this because recognizing human expressions and faces was so important to our survival as we were evolving that our brain jumps through hoops to do it! This has been dubbed the Thatcher Effect, as an early example of the illusion used British ex-Prime Minister Margaret Thatcher as an example.

Funnily enough, there’s actually another way our brains can be tricked by eyes and mouths on faces, and that’s by doubling them up. Stare at this image of a man with four eyes and two mouths:

Notice how your eyes kind of slip over it? This is because your brain is trying to find an anchor point. You know that a human should have one mouth and two eyes, so you keep trying to find the correct version of the face inside these ones.

Monster Faces

As we’ve learned, faces can short-circuit our brains pretty easily. Still, this next one takes the cake. Please stare at the cross in the middle of the screen and do not look away. See if you notice anything strange, happening.

Shocking illusion - Pretty celebrities turn ugly! by TangenCognitionLab

What’s going on here is that your brain is noticing the facial features in both the left and right images, but because they’re in your peripheral vision, the face data is incomplete. To make sense of it, your brain smooshes them together! This makes the faces seem warped, almost like caricatures when you’re not looking right at them.

Ames Room

Even if you're short, you’re probably not as short as the man in this clip below:

Ames Room at Puzzling World, Wanaka, New Zealand by Rich Hudson

What you’re looking at isn’t some sort of ethereal between-world; it’s called an Ames Room. This is a room constructed in a specially elongated way, and then decorated with out of proportion patterns to conceal depth. And so, it appears to be a totally normal room from the right angle.

As shown in the high-tech reconstruction below, it’s a pretty elaborate set-up. When viewed from the right spot, though, the effect, called perspective compression, tricks our brains into thinking something far away is actually just smaller.

ames odası / mikail güner / ames room animasyon by Mikail Güner

Ames Rooms can create some really intense visuals, where people in the foreground appear to be on the same plane as those further away, making it look like they’re vastly different sizes. Some rooms even add in furniture or decorations that are also warped in proportion and location, but that look the same relative size in a shot like the one below, helping force this perspective and making the illusion more difficult to spot!

Ames Room at Camera Obscura & World of Illusions by Camera Obscura & World of Illusions

Anamorphic

Perspective compression isn’t the only way to warp how we see the world, as artist Regina Silvera knows all too well. Back in 2010, she created the Abyssal exhibition, and it really lives up to its name.

Are these guys floating over a steep drop next to a skyscraper? Not quite. The flat gallery floor has had windows on it painted at a specific angle, but when seen from an oblique angle, the stretched windows on the floor appear like regular windows on a wall, making these guys look like they’re floating!

This is known as an anamorphic effect, and it’s mind blowing, but when applied to a much larger scale, anamorphic art gets way more interesting, as French artist JR has proven, repeatedly. Back in 2021, he applied "La Ferita" or "the Wound" onto a palazzo in Florence, Italy. If you look at it from the right angle, it looks like you’re peering right into the heart of the building through a gaping crack!

But as huge as this is, it’s not JR’s biggest work, that’d be his takeover of the Louvre museum. Back in 2019, he and an army of 400 volunteers painted the courtyard of the famous art museum:

He turned the Louvre’s famous glass pyramid roof, into an even bigger pyramid buried beneath the ground! Visitors were allowed to get up close with it, but every step they took on the paper tore it up, gradually eroding it until big holes began appearing in this gigantic illusion. That’s probably one way to see through it!

Negative Afterimage

Back to that picture of the woman from the very start of the article. How is it you were able to see this image in corrected colors when she wasn’t on the screen? Let's try again and use a different image this time. Focus on the dot, don’t blink, and keep your eyes open, and then loot at the blank screen on the right side.

That’s magical, except, not quite. It’s all down to the cells in your eyes, called ganglion receptor cells. These cells can identify pairs of colors in the images you see: black and white, red and green, blue and yellow. These channels combine, but never cross over, that’s why you never see a reddy-green, or a bluey-yellow.

So, when you stare at an inverted image, you overexpose or tire out one half of those color receptor pairs those color receptors. Then when you look at the white screen, those exposed receptors are weak, but the opposite receptors are still firing, not as strongly as the other receptors were, but more than they are once fatigued. So, the lack of green, black, and blue makes you think you’re seeing a mix of red, white and yellow, turning this negative image, into a positive image!

The Ponzo Illusion

Take a look at these images and spot which car is the largest.

In fact, none of them are the largest because they’re all the same size! So, how is this possible? It’s all to do with our sense of perspective again. You know that objects appear larger to us the closer they are. So, when we see an image like this, our brains know that the cars should be getting smaller the further away from our viewpoint they are.

So, if there’s something in an image that makes it look like things are getting further away, which in this case is the road, then our brain thinks that if the car isn’t shrinking in size, it must just be bigger! If you think we need cars, roads, and fancy rooms to mess with our perspective, then prepare to be humbled. Some of the most effective ways our brains can be tricked is with just a few lines. Here’s playing on the idea of train tracks, do the yellow lines look different in length to you?

The top one might look longer but despite what your eyes might tell you, those two yellow lines are actually the same length. The reason this happens is that the two lines on the sides slanting inwards creates a feeling of depth that we project onto the horizontal lines, even when it isn’t there.

Müller-Lyer Illusion

Even simpler is the Müller-Lyer illusion, take a look below. Which line, left or right, do you think is longer?

While the left line may appear obviously longer, they are, in fact, the same size. Once again, it’s the slanting lines that are the culprit; the left image suggests a longer horizontal line branching out, while the right suggests a shorter line being squished.

Elusive Cubes

So our sense of depth can be easily fooled in 2D images and you might think it’s easier to spot a 3D illusion. Let’s test it. Watch this next clip carefully to see if you can spot something out of the ordinary:

Lee Light - by Glen Lewis-Steele by Glen Steele

You might have been convinced that one was a cube until the very end. The light in this one interferes with the shadows, making it harder to determine it’s real shape. The outlines on the edges of these fake cubes also helps sell the illusion of depth, but again, that means they only look right from the perfect angle.

Checker Shadow Illusion

Take a look at the image below, it looks like a standard chess board but look at the squares labelled A and B. Which is the darker color? Did you think it's A?

If you think A is darker, you’re wrong, and “A” is what most people would answer. When the squares are placed side by side, they’re actually the exact same shade. This illusion works in a similar way to the last one; we all know that when a shadow is cast over an object, it’s hue becomes darker.

Here's a similar example called the Cornsweet illusion; take a look at the two gradients. Which side of the image would you say is darker; left or right?

In reality, the far ends of the image are the same shade. We see the darker shade on the left, which colors our understanding of the gradient’s progression. This sounds familiar, doesn’t it? By this point, you might be realizing that a lot of optical illusions take advantage of the fact that our brains tend to fill in the gaps much more than we realize.

It’s theorized our brains do this because of how important fast reaction times were during evolution, after all, if you were in the middle of the jungle and thought you spotted a tiger, would you rather stop and have a good think, or get the heck out of there, even if it just turned out to be a stripy rock?

This is true in all sorts of wacky ways. Look at the image below for a few seconds:

It's likely that when you first saw it, you did a double take. The perspective really makes it look like that head belongs on top of those bare shoulders, but it actually belongs to the body with the white shirt. Still, our brains would rather make a quick assumption about an image than refuse to interpret it. Our lazy brains can be tricked by the stupidest stuff!

Invented Motion

So, we stupid humans can get easily confused by still images, but motion can be just as baffling. Check out the following clip:

Crazy Circle Illusion! by brusspup

When several small circles (eight, in this case), moves in straight lines inside a big circle, something crazy happens. Instead of seeing eight individually moving circles, we’re seeing one large, rolling circle. If that one left you unimpressed, though, then take a look at these discs, but as a word of warning, if you're sensitive to flashing lights you should skip this next clip:

🔵 The Non-Moving Circles | Optical Illusion Test 🌀 by Now You See

What direction do you think they’re moving? In reality, they aren’t moving at all! Why do we think they’re moving though? Our brains tend to lump multiple elements of visual information, including motion, together.

This means when we see a bunch of smaller, moving objects, our brain tries to make sense of them by finding a way to connect them. This is how a bunch of circles moving back and forth can become a rolling circle, but it’s also the reason some wobbling squiggles on a screen can look like an animated character and not just a bunch of moving lines.

Cube Movement

On the topic of animation, take a look at the moving cubes below. See if you can tell which of the two of them is moving the fastest as they change directions and spin around:

These Cubes are Not Moving | Optical Illusions I Science by Our Space TV

Did you guess neither of them? That’s right, as hard as it might be to believe, neither of these cubes are moving. What’s actually going on is that the strobing colors and lights on the cubes are reminiscent of movement, even though the cubes themselves are totally still. As our brains try to interpret how the cubes are moving, the arrows offer a subliminal suggestion, which our brains pick up on.

Look at this even simpler version of the same trick.

Rotating Cube Illusion How It Works||Optical Illusion-Rotating Cubes by Jatis Chandra Das

How many times do you think these cubes rotate in 5 seconds? They don’t. These cubes are in fact still images, with sections of their lines strobing in a manner that suggests they’re spinning. If you pay attention to just one edge of a cube at a time, it becomes easy to spot.

Of course, the magic doesn’t come from the shapes, but from the illusion of movement. Take a look at these two color wheels, you might find that the trick works even better with these than the cubes:

Moving motionless circles (Optical illusion) ! by Virale TV ENG

The Silhouette Illusion

Focus on the spinning dancer in this next clip, and try not to look away. Paying close attention, can you guess which way is she spinning?

SPINNING BALLERINA ILLUSION by VOD102

Look at her arm and then look at her leg. She’s spinning right or is it left? Concentrate on one area, and you might just force yourself to flip the animation around. The animation is a simple loop, and you’re not being tricked. What you just witnessed is perhaps the most popular example of what’s called the silhouette illusion.

The reason it works is down to the lack of clear visual information we’re given. The dancer is clearly moving, however the fact she is in silhouette means she is completely lacking in depth. This makes it hard to tell whether she is standing on her right leg and spinning left, or her left leg and spinning right.

For another example, check out this next rotating shape.

Frank Force's dual axis rotation illusion by anomalogue

Which way does it appear to be spinning to you? Try looking at another corner of the image, then back. You'll find that you can flip this one around pretty easily. Those simple lines are able to give our brains all the information they need to decide which way the formerly-elusive dancer is spinning.

Motion Aftereffects

Let's delve into an old-school optical illusion. In fact, this is ancient school, as this illusion was written about by Aristotle all the way back in 350 BCE. Have you seen a still image of a waterfall? Your brain is going to make it move. Stare at the blue dot on this clip below and try not to look away for the next 20 seconds:

Motion Aftereffect Demo (Waterfall) by special4k4

Is that river moving backwards? Actually, it’s not moving at all. This is an aftereffect illusion, originally named the waterfall illusion in the late 1800s, supposedly because if you stared at a waterfall long enough, rocks jutting out might appear as if they were moving up the water.

However, it doesn’t just work for vertically scrolling images. Basically any spiraling, scrolling, or wobbling pattern can have an effect. If you don’t believe it, stare at the following moving pattern for 20 seconds, then look at your keyboard:

LSD Effect by Visual Trips

What do you see? Your keyboard has been turned into alphabet soup, right? How did this happen? Well, it’s all down to the visual cortex in our brain, and how we interpret moving patterns. The longer we remain fixated on a motion or a moving pattern, the more dulled the response time of cells in our visual cortex become.

Such that, when we look away from the source of that movement, our brains are essentially still looking for it, and place it over whatever we’re looking at. Interestingly, this often has the affect of creating movement inverse to what we were just looking at. This is why that river appeared to be flowing backwards.

Motion-Induced Blindness

Set your eyes on the dot in the middle of the image below, and concentrate hard. After a few seconds, you might start to notice something, or stop noticing something!

Motion-induced blindness: test for the severity of ADHD : eChalk illusion by eChalk

If you’re still looking at that dot in the center of the screen, you’re probably experiencing what’s called motion-induced blindness. It refers to a phenomenon where information in our peripheral vision seems to fade away when motion is introduced to the center of our field-of-view.

While there are numerous theories as to why this happens, one that seems to make sense is that our brain is eliminating extraneous information. That is to say, if something is rushing straight at you or you’re speeding towards something, that thing is probably more important than anything to either side of you.

Varying Speed

Take a look at the following loop:

Hardfloor - "Prot" (snippet) by HRDFLR

It just goes on forever. How fast would you say the camera is travelling here, walking pace? Zooming along? Try the following: using your hands, cover the left and right sides of the image so you’re only focusing on the center. It appears to slow down the pace. Let’s try the opposite now. Cover the middle of the clip and look at the edges. It seems that it has started zooming!

While the effect is dramatic, it makes total sense. The middle part of the image here doesn’t actually change too much as we move ahead; it’s more like the horizon is constantly, slowly coming into view. By contrast on the outer edges, details come into focus and leave in the blink of an eye.

Parallax Effect

We’ve gone over some crazy stuff in this article, and have had a lot of our pre-conceived notions questioned, but still, we can all at least agree that commercial planes can’t hover. They can fly forward, but they can’t hover. But you need to change that concept too. Take a look at this clip:

Plane appears to pause in midair in optical illusion by ABC7

What you’re looking at is what’s known as the parallax effect. It occurs when objects in motion are witnessed by a spectator whose viewpoint is also changing. It’s most pronounced when the viewer is moving faster than the observed object. The filmer is also in a fast-moving plane, creating the illusion the plane in the window is hovering in the same spot.

It’s easy to spot this effect with planes as they tend to be easy to spot themselves. However, the effect can also occur in standard photography.

Segmented Animation

On the topic of movement, here’s a fun one. Take a look at this compilation of some artwork pieces.

Amazing Optical Illusions by mrozinsky

The reason these segmented animation illusions work is similar to how a zoetrope works. Zoetropes are those physical discs or cylinders you spin to reveal a little animation. The multiple images in a zoetrope act as the frames of the short animation. When it’s spun fast enough, our eyes stop distinguishing those as individual frames and blend them together into one fluid animation.

Similarly, every frame of these segmented animations is present at once, that’s why they look like weird blobs. When a sheet of paper with missing sections is run over the static image, it blocks out certain frames whilst leaving others visible. This leads to the illusion of movement, and the animation works forwards and backwards.

Interestingly, segmenting our field-of-view can mess with our perception of speed and movement, too. Take a look at the following animation and determine whether the blocks moving at the same or different rates.

The blue block might appear slightly ahead while the yellow block is trailing a little behind. But they’re actually moving at the same speed! This is likely due to the darker bar blends in more with the dark lines, while the yellow bar sticks out, making its movement appear more segmented.

Café Wall Illusion

We’ve learned about a lot of wacky motion, animation, and camera trickery so far. For this next illusion, let's go back to something simple, as simple as you can imagine. Take a look at the picture below and try to determine whether the lines in it straight, or not.

Feels like it shouldn’t be that hard to answer, does it? Well, how about we get rid of all those weird shapes and colors and really get down to basics:

Those two images are examples of what have come to be known as the café wall illusion, and the lines in both of them are surprisingly completely straight. If you zoom in, you'll see that the lines don’t slope at all! What’s going on here? The really mind blowing thing is no one really knows!

Since it was first discovered by Hugo Münsterberg back in 1894, the leading theory has been that it comes down to the way our brains interpret contrast. Different neurons in our brains respond to dark and light colors. This means the darker lines between the white and black squares are being simultaneously interpreted in two different ways, which causes the illusion of sloping lines.

In the first version of the illusion, the same effect is perhaps being triggered by the little checkered squares running along the horizontal lines. However, that’s still only a theory! But it’s a theory that would explain why it isn’t limited to just horizontal patterns. Check out this next variant:

While this image may appear to be a deep, spirally vortex, looking closer will reveal that those circles don’t connect at all. It’s just multiple circles, not a spiral! Here’s one final image, take a look.

The lines don’t appear to slope, but bulge, like the image is being pinched or squeezed. Still, when we zoom in, we can see that every line in the image is perfectly straight. What café would put something this disorienting on a wall?

The Coffer Illusion

Look at this image below:

What shapes do you see? Squares, right? Maybe you saw lines but you probably didn’t see circles, though. However, there are circles in this image. Can you see them? They're between each square shape.

This is known as the Coffer Illusion, and was created by the Neural Correlate Society in 2006 as an entry for the Best Illusion of the Year Contest which. While you almost certainly picked up on the rectangular shapes first, if you stare hard enough, you’ll find the vertical bars actually create perfect circles.

One theory on this illusion posits that when visual information is unclear, our brains are more likely to search for corners or hard angles as they’re anchor points from which we can try and make sense of the rest of the information. Who knew corners could be so confusing?

I hope you were amazed at these mind-blowing illusions! Thanks for reading.