- List of incredible optical illusions
- Growing bat
- Floating star
- Fading image
- Monster illusion
- Panda bear
- Where are the forest animals?
- Green Blue
- Cat climbing stairs ... or is he going down?
- The image of the old / young woman
- Dancer
- Pac-man illusion
- Zöllner's Illusion
- Movement illusions
- The circles that move ...
- The illusion of the shadow
- The twinkling grid or glowing grid
- Cornsweet effect
- How big are the cars?
- Jastrow Illusion
- Ames room
- Square illusion
- Where is the chair facing?
- Rotating circles illusion
- Circle size illusion
- How many legs does the elephant have?
- Müller-Lyer illusion
- Optical illusion of center point
- Rubin's Vase
- Two women or ...
- Double image illusion
- White-black circle-Koffka ring
- Blivet 2-3
- Street painting
- Pareidolia
- Light bulb
- Squares that seem to move
- To hallucinate
- Man or horse?
- Boats and bridge
- Giant seagull
- Mouse or lion?
- Whole glass or half glass?
- Causes of optical illusions
- Physiological
- Cognitive
- Some investigations
- Classification of optical illusions
- References
The optical illusions are visual perceptions that do not conform to the reality of the world in which we live but belong to perception. They tell us a lot about how we see and rebuild everything around us from our perspective.
In fact, all we see is a reconstruction that the mind makes of the reality that surrounds us. The brain, taking into account its innate knowledge about reality, compares that knowledge with everything it observes and draws its own perception and conclusions.
In particular, the human being interprets 80% of reality. That is, we only see 20% of the world as it is, the rest is interpreted. So it can be said that reality depends on how you interpret it.
Thanks to the effect of optical illusions, we realize that what our eyes see is not objective, but rather the brain comes into play in the process of seeing. Thus, the brain interprets and reworks the information provided by our senses (smell, sight, hearing, smell, and touch).
In the case of optical illusions, the sense involved is sight and distortion can be caused in relation to shape, dimension, color and perspective.
The use of perceptual deception is something that has always been used on an evolutionary and survival level. We only have to think of the multitude of insects and even predators that camouflage themselves taking advantage of the fact that they have the same color as something in their natural environment.
Also, humans use perceptual deception for survival. The military uniforms are designed so that weapons, which also have the same color, go unnoticed in the distance.
List of incredible optical illusions
Next, I am going to explain, including images, the most amazing optical illusions. Depending on your smartphone model, they may not be well perceived. If you do not see them, in computer / laptop / computer it is sure that (verified)
Growing bat
Image created by G. Sarcone
It's not a video or a GIF, I assure you. This is an optical illusion in which a static image appears to be moving due to cognitive effects produced by interactive color contrasts and the position of the bat shape.
Try to fix your gaze on the bat for 10 seconds without blinking and you will literally hallucinate.
Floating star
Authors: JOSEPH HAUTMAN / KAIA NAO
Oddly enough, the star above is static, it is not moving. Carefully arranged transitions between white, light-colored, black, and dark-colored regions trick neurons into responding as if they are seeing continuous movement in the same direction, rather than static edges.
Fading image
Stare at the image for at least 30 seconds without moving your eyes and watch it disappear little by little. This is a variation of the Troxler effect that essentially says that if you fix your eyes on a certain point, the stimuli near that point will gradually fade away.
Monster illusion
This illusion can be found in many books on Psychology. Although one may appear larger than the other, the two monsters are in fact the same size. Your brain automatically adjusts the images it perceives as distant to compensate for the fact that they are larger than they appear.
If you don't think they are the same size, find a meter and measure them.
Panda bear
In an attempt to help raise awareness of the panda's plight, Russian artist Ilja Klemencov created this optical illusion, which contains a panda hidden behind zigzag black and white lines.
If you cannot see it, try: move up to one meter from the screen, move your head to the left, right or both sides.
If you spot the panda you will notice that it is the famous logo of the World Wildlife Fund (WWF).
Where are the forest animals?
Green Blue
There are several variations to this optical illusion, but the effect is the same. The "blue" and "green" backgrounds are in fact the same color.
You do not believe me? Isolate the two images in photoshop or with paint and you will see it.
Cat climbing stairs… or is he going down?
The image of the old / young woman
We start the article with one of the best known illusions. Surely you know her too. It is an image in which a young woman or an old woman can be seen indistinctly depending on the moment and the perception. One of the two is always seen before the other.
Dancer
Created by web designer Nobuyuki Kayahara, some people see the figure spinning clockwise, while others see it spinning counter-clockwise.
What do you think? Leave your opinion in the comments!
Pac-man illusion
If you stare at the cross in the center for at least 15 seconds you will begin to notice several green lights around the circle of magenta discs. After a few more seconds, the magenta discs will start to fade until all you see is a green disc circling the cross.
Zöllner's Illusion
This illusion was discovered by the German astrophysicist Johann Karl Friedrich Zöllner in 1860, hence its name. In the image, several small lines are seen. Although they appear to lean, this is an optical illusion due to the diagonal lines. Small lines are actually straight.
Movement illusions
These images are static, even though there appears to be movement. To check it, cover a part of the image and you will see how there is no movement.
The circles that move…
They don't move, although it does stop your brain. The colors and shadows are responsible for the feeling you have when looking at this image that the circles are moving. This illusion affects peripheral vision.
If you notice, if you fixate on one of the circles, the circles will surprise us moving. This image is based on the work of psychologist Akiyoshi Kitaoka.
The illusion of the shadow
Probably one of the most incredible illusions there is, it was published by Edward Adelson, a professor at MIT. Although square "A" appears to be darker than square "B", they are the same color.
The twinkling grid or glowing grid
This illusion was discovered by the author E. Lingelbach in 1994. In it, if we do not look at a specific point and dedicate ourselves to looking at the image in general, we perceive black points and white points alternating at intersections.
On the other hand, if we look at any intersection fixedly (we can do this with several intersections), we will verify that there are no black points. Again, this is a product of our perception.
Cornsweet effect
In this effect, the visual system takes the dark gray and white from the edges and spreads it across the squares.
In the image, if you put your finger in the middle of the two cubes, you can see that both cubes are the same color. On the other hand, if you remove your finger again, you will see the top one darker than the bottom one.
How big are the cars?
In the image above it seems that the cars are of different sizes but… Look at the following image:
Jastrow Illusion
The discoverer of this illusion was the American psychologist Joseph Jastrow in 1889. In the image below, it seems to be observed that figure A is smaller than figure B. It is not so, both are the same.
As this illusion is difficult to see that what I am telling you is real, here is a video where it is explained very well how both figures are the same size.
Ames room
This illusion owes its name to the American psychologist Adelbert Ames, who created this room.
It has the peculiarity that, although it seems normal when viewed from the front and in the center, it is actually trapezoidal. That is, both the walls and the floor and ceiling are sloping. Below I show you a plan of how the room is made.
So that you can see it in a very visual way, I leave you this video in which the effect of the illusion is perceived:
This illusion has been used in the cinema, in the well-known movie "The Lord of the Rings."
Square illusion
The square of the image appears to be uneven. Instead, it is completely regular. This is because the way the black squares are arranged makes us see it distorted.
Where is the chair facing?
Rotating circles illusion
In order to perceive this optical illusion, we have to fix our gaze on the center point for a few seconds. Next, we will throw our heads back and forth. Can you see how the circles move?
Circle size illusion
The author of this illusion is Ebbinghausen. In this image, both circles are actually the same size even though we see them differently (the one on the left is larger than the one on the right).
This is due to the circles around him. Because the adjacent circles on the left are smaller, the middle circle is larger for this reason. The effect is the opposite in the image on the right. As the surrounding circles are larger, the circle in the center is perceived smaller.
How many legs does the elephant have?
It only has 4 legs!
Müller-Lyer illusion
Looking at the image, the line in the center of the image on the right appears longer. However, this is due to the placement of the horizontal lines at the ends.
Being in an outward orientation, the center line is perceived to be longer in the image on the right. That is, there is an effect of lengthening or shortening the length of the segment.
Optical illusion of center point
This illusion is perceived if we keep our eyes on the central point of the image below. When we do this, the dark center of the image expands. In reality there is no such expansion. It is the product, once again, of perception.
Rubin's Vase
This is another of the most famous optical illusions as it has been used in Gestalt Psychology. It is within the cognitive illusions of ambiguity
. It was developed by the Danish psychologist Edgar Rubin in 1915 in his work Synsoplevede Figurer (in Spanish, Visual Figures). This image represents a double vision, on the one hand that of a vase and on the other that of two faces looking at each other.
Two women or…
Double image illusion
In this other image, you can see both a saxophonist and a girl's face, although one is usually perceived faster than the other depending on the person. Can you see both?
An optical illusion that we find on a daily basis is the one used in the cinema. In this art certain effects related to animation are used, considered this as an optical illusion since a movement is perceived in something really static.
They are also and have been widely used in a number of works of art with the aim of causing a false impression of form, dimension, depth or perspective in the viewer.
The mental alteration that a person can suffer at a certain time, or even permanent, can also cause involuntary optical illusions to appear.
Studies show that the longer the observation time, the greater the distortion experienced.
White-black circle-Koffka ring
The first semicircle on the left appears to be white, while the semicircle on the right appears black… However, they are the same.
You do not believe me? Isolate the semicircles with your hand and you will see.
Blivet 2-3
This is one of the most famous optical illusions of an object. It has 2 rectangular prongs on one end that transform into 3 cylindrical teeth on the other.
Street painting
Pareidolia
Do you see anything else besides the mountain?
A pareidolia is an illusion created by the brain to see faces in nature or in other places, such as houses, bags or any type of object.
Light bulb
Stare at the light bulb for 25 seconds. Then look at a white sheet or white wall. Do you see?
You should see a see a bright light bulb.
In conclusion, we can say that the brain receives so much information that they tend to jump quickly to conclusions based on what it already knows and that, beyond what we could imagine, we do not objectively observe the world around us.
Squares that seem to move
Akiyoshi kitaoka
To hallucinate
Author:
Have you ever wondered what it feels like to hallucinate? Well now you can do it with this illusion. If you stare at the center of this illusion you will see that you start to see different movements. Also, every time you blink or look elsewhere, the movement will change.
If you stare for 30-60 seconds and then look into the room you are in, you may still see "hallucinations."
Man or horse?
Boats and bridge
Giant seagull
Although it may seem otherwise, the seagull is not giant. It seems so because she is close to the lens of the camera that took the photo, while the man behind is far away.
Mouse or lion?
Whole glass or half glass?
Author:
Yes, it is a whole glass, even though it appears to have an inward opening.
Causes of optical illusions
In addition to being the cause of the brain, there are other causes why optical illusions occur. Next, I will go on to detail the various causes:
Physiological
We can speak of physiological causes of an optical illusion when it occurs due to a glare due to an intense light stimulus that leaves the light receptors of the retina saturated for a few seconds. This is due to errors in the connections between the cerebral hemispheres.
An example of optical illusions due to physiological causes are afterimages. After images are the images that are apparently imprinted on our eyes after observing a very bright object. In general, they occur as a result of an excess of visual stimulation, be it movement, brightness, color, etc.
The explanation for why this occurs is that stimuli have individual neural pathways for the early stages of visual processing, and repeated stimulation of only some of these paths confuses the visual mechanism.
Cognitive
They are based on the vulnerability of the visual system. Thus, a figure will appear to be a thing that it really is not.
Cognitive illusions are divided into: fictitious illusions (or hallucinations), paradoxical illusions, distortion illusions, and, finally, ambiguous illusions.
The perception of optical illusions varies from one person to another, and several factors are involved in this variance, such as visual acuity, visual perimetry or perimetry, astigmatism or color blindness.
Some investigations
The investigations of the author Gregory (1969) showed that taking into account that the correspondence of the properties perceived visually and the objective ones is called constancy, and, on the contrary, the non-correspondence is called illusion, there is a pole constancy-illusion.
Between these two extremes, there can be an infinity of perceptual outputs. The result of perception will depend on the information acquired through the stimulating medium, with the keys of depth and perspective having special importance.
This author classifies illusions into 3 types:
- Impossible objects: these are figures that cannot be perceived as a single object only.
- Distorted figures: these are figures that appear longer, or shorter, or improperly curved.
- Figurative post-effects: it is the illusion that occurs in a certain figure as a result of having perceived, immediately before, another different figure.
Although there is no unified theory of all illusions, authors David Hubel and Torsten Wiesel discovered through research that there are certain neurons located in the visual cortex of the brain that are activated only when we observe objects oriented at certain angles.
More recently, a study in which Necker's Cube was studied, it was observed that in people who observed this cube, the brain could vary between two different interpretations of the same image, while trying to convert a two-dimensional image into a three-dimensional one.
Classification of optical illusions
- Figurative illusions: they are distortions of position, size, length or shape alterations. These occur in linear representations and are produced because of the ocular fixation on a previous form. That is, they are phenomena of contrast between successive figures. An example of this kind of optical illusion is the Müller-Lyer illusion.
- Illusions in three dimensions: these often occur when two series of visual information are brought together at the same time. An example of this illusion is Ames's distorted room.
- Linear illusions: are those that occur directly because of the special arrangement of the lines. An example of this is the Zollner illusion.
References
- Franz VH, and Scharnowski F. Gegenfurtner. 2005. "Illusion effects on grasping are temporally constant not dynamic." J Exp Psychol Hum Percept Perform. 31 (6), 1359-78.
- Franz VH, and Scharnowski F. Gegenfurtner. 2005. "Illusion effects on grasping are temporally constant not dynamic." J Exp Psychol Hum Percept Perform. 31 (6), 1359-78.