25 Optical Illusions That Prove Your Brain Sucks

This would be a perfectly nice grid, except it's all crazy and nuts on the sides. If only there was a way to fix it! There is! Sort of! If you stare at the center of the grid, the crazy peripheries begin to fix themselves. It is thought that the brain has a bias towards order and regular patterns and will actually go about "fixing" the problems on the sides. (Source)  

Hit play above and then stare at the screen. The image will change along the way and your brain will add an interesting temporary effect. (Toggle backwards to confirm reality.) This is an example of an afterimage, where the eyes' receptors are so stimulated that they still tingle after the fact. In this case, they overcompensate with complementary colors (i.e. the solid, vivid white turns black; the orange turns blue; and the blue turns fleshy).

The answer is zero. Despite what your eyes are telling you, there are no black dots. There are only white dots that appear to darken in the periphery of your vision. This is an example of a scintillating grid illusion. While scientists have various theories, there is actually no consensus on why this illusion works, other than our brains are all stupid sometimes.

Watch the above video. Not only does your mind misinterpret what it sees in the foreground, it doesn't seem to understand what's going on in the mirror image in the background. This misunderstanding takes place because 1) the brain can't accurately render depth from a single vantage point (i.e. a video) and 2) the brain likes to "see" right angles (the kind that would occur should the curve of the roof continue—it would meet a plane perpendicular to the axis of the roof). (Source)

This image is not animated. Don't believe me? Try staring at just one part of the image and you'll see it will stop moving. This is an example of a "peripheral drift illusion." It is thought that this illusion occurs because of the slight differences in time it takes to process different luminances (how intense the light is from a particular area). This slight lag in mental processing tricks the brain into perceiving movement that isn't really there.

The above circle is just a series of dots rotating within a larger circle, right? What could be more obvious? Watch the video to see just how this rotating ring is something completely different, and your brain can't pick up on it.

Despite what your eyes are telling you, they are. It is thought that the café wall illusion functions due to the high contrast in the two different "bricks." When interpreting images, our brains tend to "spread" dark zones into light zones, a function known as irradiation; this "movement" is probably what causes a false warping effect.

Stare at this image and you'll see how the flickering circles in your periphery appear to be moving even though they are absolutely stationary (try staring at just one and you'll see). This illusion is attributed to the Cornsweet effect, which is what happens when the brain fills in information based on slight changes in gradient. (Source)

They're both exactly the same! This is an example of the Ponzo illusion. This little trick takes advantage of the human brain's use of background to judge an object's size. (Image)

Your brain is a powerful thing, but it can be tricked—sometimes quite easily. And here's one other weird wrinkle: it can consciously trick itself. The above is a prime example of something called pareidolia, whereas the brain perceives a familiar pattern where there is none.

In the case of the video above, the mind perceives movement where none actually existed—it's just random static. But, as you see, the mind can control the direction of the apparent movement just by thinking "left, right" or "up, down." (Source)

Here's an illusion utilizing the Dynamic Luminance-Gradient Effect, and it requires your participation. Move closer to the screen and you'll see the white shade in the middle explode in luminance.

Stare at the black cross in the middle of this graphic. Soon you'll begin to see a green dot moving around the perimeter. Eventually, all the pinkish dots disappear, leaving a lonely solo green dot traveling along the edge. But it's all a lie. There is no green dot and the pink dots never really disappear.

This is known as the lilac chaser illusion. It's a combination of several physiological phenomena including the previously mentioned "phi phenomenon" in which we perceive continuous motion between separate objects viewed rapidly in succession (used in development of early cinema).

It also includes the afterimage effect in which overstimulation of specific cones in the eye can "tire" them out while surrounding cones not affected by that particular stimulation will send the brain the complete opposite stimuli (in this case, green).

Since our brains tend to ignore blurry stimuli that are in the periphery of our vision, a phenomenon called Troxler's fading also takes place.

Yep, your brain sucks again. The orange circles are exactly the same. This is known as the Ebbinghaus illusion. It is theorized that the two main visual contributors to this illusion are the difference in the distance between the outer ring and inner circles as well as the completeness of the ring surrounding the "smaller" circle. Here's an animation that explains the illusion in real time.

Here you find a series of slits roving across an illustration, thus allowing only small bits of information at a time. Our brain then fills in the gaps of different stages and recreates the experience of viewing fluid movement. If you're feeling dumb and disappointed in the power of the human brain, don't—as you can see, the cat in this video was also fooled.

It doesn't. That's more lies our brain tells us. There are no shades in this image, only lines. This is known as the watercolor illusion. This is what happens when a polygon has a border made of a bright line, bordered by a darker line of a complementary color: your brain is tricked into "filling in" the shape with the brighter color. (Image)

We've seen numerous examples of afterimages, whereby the brain is prompted to "see" colors that aren't there based on earlier stimuli. However, as the above video shows, the story of after images is even more complex: The brain can be tricked into seeing different colors based on the size of subsequent stimuli. (Source)

What a good-looking spiral, amirght? I guess nothing more to discuss here… unless… no, wait a minute. Run your finger along the spiral and see if you can run the length of it. Something seems off here.

This is the Fraser spiral illusion. Despite what your eyes tell you, the spiral is actually a series of concentric circles. The background pattern makes the picture so confusing that your brain just fills in information that isn't really there.

Watch the above video. Think those letters are moving? They're not. You could simply trust me or the maker of the video on this point, or you can verify yourself. Take a straight-edge like a sheet of paper and hold it over the tops of the letters—you'll see that they are perfectly stationary. The changing fill-shade fools the brain into seeing movement that is not occurring. (Source)

At first glance, you should see a semi-transparent blue circle overlaying the illustration, but you aren't really. The light blue blotch is the result of an illusion known as neon color spreading. Similar to the watercolor effect, your brain has been tricked into adding color into the bare negative spaces.

This is one of the most effective illusions I've ever come across. If you concentrate on the center and read the letters as they go along, you will find a swirling vortex of shapes and colors forming around the periphery (but no colors have been added—it's all an illusion). The effect even lasts for a powerful few seconds after you've stopped watching. Whoa.

Stare at it for a bit. You'll figure out what's going on here. This is a form of a cognitive illusion, called the Shepard elephant, in which our assumptions about the world are challenged in a falsified image.

There is a phenomenon around the world called a gravity hill, where a downhill slope in the road looks like an uphill slope. This creates the optical illusion that water runs uphill and cars can coast backwards up the hill. While many urban legends exist to explain these spots, it has more to do with how the road is oriented compared to the horizon than anything magnetic or supernatural.

This classic wire-frame drawing is called a Necker cube. With no visual cues to determine the cube's true orientation, this optical illusion causes your brain to think the front-facing side is oriented towards the top right or the lower left.

The Spinning Dancer illusion depicts the silhouetted image of a dancer spinning in a circle, but what direction does she spin in? Some say clockwise, others say counterclockwise, and many have reported that the illusion actually changes direction. The reason is that without a proper reference point for depth, the brain is tricked by the figure's shape and orientation as it turns.

One of the more famous objects is the impossible trident, which has three cylindrical prongs on one end but only two square prongs on the other. The image uses negative space to trick the viewer into thinking that each side makes sense, but the entire object remains impossible.