Munker Illusion

These are examples of the Munker illusion.

In the examples, the shapes are all the exact same color. They only appear different back on the contrasting background colors.

The Munker illusion is a visual illusion in which two identical gray squares appear to be different shades of gray when they are placed on a patterned background. The illusion was discovered by German psychologist Paul Munker in 1970.

If you are interested in learning more, scroll down to learn more about it.

Munker Illusion
Munker Illusion
Munker Illusion


Table of Contents

What is the Munker Illusion?

The Munker illusion is a visual illusion in which two identical gray squares appear to be different shades of gray when they are placed on a patterned background. The illusion was discovered by German psychologist Paul Munker in 1970.

The Munker illusion is created by the way that the visual system processes contrast information in the image. The patterned background surrounding the gray squares creates a gradient of contrast that changes the perceived brightness of the squares. The gray square on the lighter part of the pattern appears darker, while the gray square on the darker part of the pattern appears lighter.

The Munker illusion is particularly interesting because it challenges the idea that the perceived brightness of an object is solely determined by its physical luminance. Instead, the illusion demonstrates that the surrounding context can also influence the perception of brightness and contrast.

The Munker illusion is an example of a simultaneous contrast illusion, which occurs when the perception of an object is influenced by the characteristics of its surrounding context. Similar illusions include the famous checker shadow illusion and the White’s illusion. These illusions demonstrate the complex ways in which the brain processes visual information and highlights the importance of context in visual perception.

How does the Munker Illusion Work?

The Munker illusion is a visual illusion that occurs when two identical gray squares appear to be different shades of gray when they are placed on a patterned background. The illusion works by exploiting the way that the visual system processes contrast information in the image.

The patterned background surrounding the gray squares creates a gradient of contrast that changes the perceived brightness of the squares. Specifically, the squares on the lighter parts of the background appear darker, while the squares on the darker parts of the background appear lighter. This happens because the visual system is constantly trying to adjust for differences in lighting conditions in the environment, and it uses the surrounding context to help determine the true brightness of an object.

In the case of the Munker illusion, the visual system uses the surrounding pattern as a reference point to determine the brightness of the gray squares. The lighter parts of the pattern make the squares appear darker, while the darker parts of the pattern make the squares appear lighter, even though they are actually the same shade of gray.

The Munker illusion is a type of simultaneous contrast illusion, which occurs when the perception of an object is influenced by the characteristics of its surrounding context. Similar illusions include the checker shadow illusion and White’s illusion. These illusions demonstrate the complex ways in which the brain processes visual information and highlights the importance of context in visual perception.

Some Similar Illusions to the Munker Illusion

There are several other illusions that are similar to the Munker illusion and also rely on the concept of simultaneous contrast. Here are a few examples:

  1. Checker shadow illusion: This illusion was discovered by Edward Adelson in 1995 and is similar to the Munker illusion in that it involves a checkerboard pattern that influences the perceived brightness of two identical gray squares. In this illusion, a shadow is cast over one of the squares, making it appear darker than the other square, even though they are the same shade of gray.
  2. White’s illusion: This illusion, discovered by illusionist and psychologist James White in 1979, involves two identical gray circles placed on different colored backgrounds. The circles appear to be different shades of gray, with the one on the darker background appearing lighter and the one on the lighter background appearing darker.
  3. Cornsweet illusion: This illusion involves a gradient of shading that makes a rectangle appear to have a three-dimensional bulge in the center. The illusion works by exploiting the way that the visual system processes changes in contrast, making the gradient appear to be a curved surface.

These illusions, like the Munker illusion, demonstrate how the brain uses surrounding context to interpret visual information and can lead to surprising and counterintuitive results.

Discovery of the Munker Illusion

The Munker illusion was discovered by German psychologist Paul Munker in 1970. Munker was interested in studying the effects of contrast on visual perception and developed the illusion as a way to explore how patterns and backgrounds can affect the perceived brightness of objects.

His discovery of the Munker illusion was an important contribution to the field of visual perception and has been studied extensively in the years since its discovery.


References and Resources

Check out our complete list of illusions.