How is deception different from illusion?

Optical illusion: 9 fascinating examples + explanation

An optical illusion confuses the senses. Although the images are static, we see movements or lines that do not even exist. A pure illusion. But how does it come about and what happens in the brain? An explanation - with many examples and optical illusions to print out ...

➠ Content: This is what awaits you

➠ Content: This is what awaits you

What is an optical illusion?

An optical illusion (also called "visual illusion") is a perception illusion. Sensory perception and interpretation are deliberately misled by contradicting information. This causes astonishment, but is also fun because you can no longer trust your own eyes. Normally the eye works reliably. We trust our perception. But not with the optical illusion. Here we see selectively: What we see is OUR reality - but not THE reality. The visual stimulus is misinterpreted. The (wrong) picture is created in the brain alone.

Types of optical illusions

Optical illusions are created using various tricks. A distinction is made between different types:

  • Size illusions
  • Perspective illusions
  • Flip figures and picture puzzles
  • Color illusions
  • Impossible shapes
  • Geometric illusions

You can find many examples of optical illusions in the images below. You will also receive an explanation of how and why the optical illusion works.

The Hermann grid illusion

How does the optical illusion work?

"Ninio’s Extinction Illusion" is the name of the work of art that Will Kerslake originally posted on Twitter. The picture shows twelve points. However, it is impossible to see all twelve at the same time. If you focus on one or two, the others disappear from the field of view. The optical illusion is a variation of the Hermann lattice illusion: the lattice pattern makes the intersection points appear lighter, while the darker points disappear at the same time.

These illusions also include color illusions. The best-known example: the picture of a dress that was posted on Twitter under the hashtag #TheDress. Many saw it as a white dress with gold applications. In fact, it was (according to the manufacturer) a blue dress with black applications.

The Münsterberg or coffee house deception

How does the optical illusion work?

All of the orange lines in the picture are perfectly parallel. All rectangles are the same size. However, the longer you look at it, the more the lines seem to bend. Especially around the edges. This is due to the contrasts, which are perceived more strongly than the lines.

The Müller-Lyer illusion

How does the optical illusion work?

This example of an optical illusion is known as the "Müller-Lyer Illusion". The perception is disturbed by complementary elements and an illusion of size. Both lines are the same length. But perception says something else. This category also includes illusions of depth or perspective illusions of size.

The Ebbinghaus illusion

How does the optical illusion work?

By this optical illusion, you mean that the upper left inner circle is smaller than the lower right. Not correct! Both inner circles are identical. Because they are surrounded by circles of different sizes, their size is put into perspective and changes. As with people in real life (see cheerleading effect)

Phantom images through optical illusion

How does the optical illusion work?

This is a so-called "phantom image". If you look at the black point for a long time and then also at a white wall or ceiling, you will see the rainbow in real colors. The reason for this is a desensitization of the receptors in your eyes. Experts also speak of a "negative afterimage". If you stare at dark colors for longer, you will see them as bright in the afterimage and vice versa. One of the most famous phantom images shows the supposed Jesus as an optical illusion.

Optical illusion through the illusion of movement

How does the optical illusion work?

The illusion of movement is a sham movement. You are looking at a static image. Still, everything seems to be moving. There is something hallucinatory about many of these images. The optical illusion is caused by repeating patterns. Different strong contrasts lead to misinterpretations in the brain. Reason: If there is no clue for a spatial location, the feeling of movement arises.

Picture puzzles as optical illusion

How does the optical illusion work?

This optical illusion is created by illusion of shape. What do you see in the picture above? The motif is circulating on the Internet as a kind of self-test for dirty thoughts. Of course it's nonsense. Even if most people see a female torso first, it can also be two dancing stick figures who pull their arms upwards. A typical picture puzzle (here the resolution). There is an “ambiguity” behind this: there is a “positive” and a “negative” of the image. The representations of two facing faces, which can be recognized as black outlines, are classic. The gap between the faces is often interpreted as a vase.

Tilting figures as an optical illusion

How does the optical illusion work?

The tilting figures are closely related to the picture puzzle. Also called "tilt images". The above picture shows a drawing by the American cartoonist William Ely Hill. It was published under the title "My Wife and My Mother-In-Law". According to a study by Flinders University, which of the two women you recognize first is a question of age: young woman or old woman? If you see the young woman, you are (stayed) young yourself.

Impossible figures as an optical illusion

How does the optical illusion work?

"Impossible figures" are also popular among the optical illusions: Geometric drawings such as the well-known "Penrose triangle" or this cube. The constructs are also part of the tilt figures. These are two-dimensional objects that simulate three-dimensionality. This leads to the fact that the perception changes spontaneously if we look at it for a longer period of time. They are therefore also referred to as “multi-stable constructions”, “change of shape” or “change of perception”.

How do optical illusions arise?

There are several methods of creating an optical illusion and tricking the eye. The deception is always based on the wrong interplay of perception by the eyes and interpretation by the brain. The explanations:

  • Processing of sensory stimuli
    Some optical illusions only work because the eye not only perceives information, but filters it. What is classified as unimportant does not even reach the brain. It also works the other way around: things that we think we know are completed. In doing so, we fall back on memories and experiences. The brain then tries to organize the images into a meaningful result. Optical illusions manipulate the process and play tricks on the brain.
  • Confusion due to wrong relations
    Many optical illusions work with wrong relations. An object that stands by smaller things appears larger. It is difficult for the human eye to determine such relationships. This also applies to colors, by the way. Two squares of the same color suddenly no longer appear so identical on a background of different light or dark. For other optical illusions, the location or perspective is decisive.

Who discovered optical illusions?

Art has long worked with illusions. The most famous representatives include the Spanish painter and eccentric Salvador Dali. He is considered the main representative of surrealism. Likewise the Dutch graphic artist Maurits Cornelis Escher. He is known for his perspective impossibilities. His pictures show stairs that are seemingly infinite like the lithograph “Treppauf / Treppab”.

Illusionistic painting can be traced back to antiquity. In the Renaissance, architectural elements were simulated in churches or palaces by means of perspective painting, the “trompe-l’œils” (“fool the eye”) in order to make the room look larger.

Experienced illusions in everyday life

We also encounter optical illusions in everyday life. Optical illusions and illusions that can be experienced are, for example:

  • Afterimage
    Turn on a lightbulb for a few seconds and look inside. Then look into the room. Suddenly the light bulb appears in everything you look at.
  • Mirage
    The mirage is created by intense heat. When the floor is heated, the air heats up and expands. The rays of light break where cold and hot layers of air meet. There is a mirage at the boundaries of the layers. In this way, objects can be mirrored that are actually several kilometers away.
  • landscape
    Optical illusions even lead to conspiracy theories. For example at the Scottish mountain "Electric Brae". Here, cars seem to be rolling uphill along the A719. This led to speculation about geomagnetic radiation. In fact, it's just the mountain backdrop that creates the illusion.

3 tips to question your own perception

Optical illusions and illusions can be used wonderfully to question your own perception. With these three questions you can:

  • Are there other explanations?
    Those who rely on the obvious explanation may be thinking too briefly. So you can fall for a wrong perception and optical illusion. Teach yourself to find alternative explanations.
  • Do I know all the information?
    Often we only see a small part of the whole. We try to get a complete picture from this. Try to question your perception and not rely on the first assessment.
  • Am I looking at other points of view?
    Perception is extremely shaped by one's own point of view. However, opinions, views, prejudices or ways of thinking can be deceptive. Therefore, change your perspective in order to break through thought patterns.

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