Jastrow Illusion

The Jastrow illusion is created by two identical shapes, usually circles, placed side by side, and one appears to be much larger.

The illusion is that the one circle appears to be much larger than the other, but in realty, the shapes are the same size.

Jastrow
The Jastrow Illusion

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How does the Jastrow Illusion work?

The Jastrow illusion works by the way the brain processes the relationship between the two circles.

One theory of why this happens is that the brain tries to find a relationship between the two circles, and when it sees that one is larger than the other, it automatically assumes that the larger circle is farther away and the smaller circle is closer. Because the brain perceives objects that are farther away as being smaller and objects that are closer as being larger, it overcompensates and perceives the larger circle as much larger than it actually is, and the smaller circle as much smaller than it actually is.

Another theory is that the brain is sensitive to the relative size of objects and relies on relative size to infer distance, which is known as size-distance illusion. When the two circles are placed side by side, the relative size of the circles can be used by the brain to infer depth and distance, and this leads to the illusion.

Additionally, the Jastrow illusion is also related to the concept of surround suppression, which is the phenomenon that the visual system is more sensitive to the stimuli in the center of the visual field, than at the periphery. The brain is more sensitive to the stimuli in the center and suppresses the stimuli in the periphery, leading to an illusion of size difference.

It’s worth noting that the Jastrow illusion is not a unique property of human vision, many animals have this ability as well.

Versions of the Jastrow Illusion

The following shows Jastrow Illusion in action:

Jastrow GIF



Illusions like the Jastrow Illusion

The Jastrow illusion is a type of size illusion, also known as a relative size illusion. It is created by placing two identical shapes, usually circles, that are slightly different in size side by side and connecting them with a line.

This illusion is caused by the way the brain processes the relationship between the two shapes, and it is a result of the brain’s tendency to use relative size as a cue for distance and depth perception.

The following are some illusions similar to the Jastrow Illusion:

The Cafe Wall Illusion is a geometric optical illusion that is created by the alignment of parallel lines in a checkerboard pattern. The parallel lines appear to be tilted or slanted, even though they are actually straight.


Cafe Wall Illusion
The Café Wall Illusion

The occlusion illusion is a perceptual phenomenon in which the presence or absence of an object can affect the perception of another object.



The moon illusion involves the perception of the Moon appearing larger when it is near the horizon compared to when it is high in the sky. The illusion is an optical illusion and is caused by the way the human brain perceives size and distance.



The Zöllner illusion is a visual illusion in which parallel lines appear to be angled due to the presence of intersecting lines.

The illusion is often used to study the brain’s perception of shape and spatial relationships. It is considered one of the most powerful and striking examples of a geometrical-optical illusion. The perception of the illusion can be explained by the brain’s tendency to group lines together based on their similarity in direction and spacing, which can lead to an overestimation of the angle between the parallel lines.

Zöllner illusion


The Müller-Lyer illusion: This illusion involves lines with arrowheads at the ends, which can make a line appear longer or shorter depending on the direction of the arrowheads.

müller-lyer illusion



The Poggendorff illusion is a visual illusion in which the brain perceives a diagonal line as being interrupted by an object, even though the line is actually continuous. The illusion is created by the misalignment of two parallel lines that are intersected by a third line at a certain angle.


Poggendorff illusion transparent gray bar


The Ebbinghaus illusion (also known as Titchener circles) is a perceptual illusion in which the perceived size of a central circle is affected by the size of the surrounding circles. The central circle appears smaller when surrounded by larger circles, and larger when surrounded by smaller circles.





The Wundt illusion is an optical illusion produces an inversed effect compared to the Hering Illusion. The vertical lines are both straight, but they may look as if they are curved inwards.

Wundt Illusion



Discovery of the Jastrow Illusion

The Jastrow illusion is a visual illusion that was first described by the psychologist Joseph Jastrow in 1889.

Joseph Jastrow was an American psychologist and author.

He was born in 1863 in Poland and immigrated to the United States with his family as a child.

He received his Ph.D. from Johns Hopkins University and later taught at the University of Wisconsin-Madison and at Brown University.

Jastrow made significant contributions to the field of psychology, particularly in the areas of perception and cognitive psychology.

He is best known for his work on visual illusions, including the Jastrow illusion which is named after him. Jastrow died in 1944.

References and Resources

Check out our complete list of illusions.

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