Benham’s Top

The Benham’s top illusion is the visual effect created when the top is spun, in which the pattern appears to change colors.

The illusion is caused by the phenomenon of persistence of vision, in which the brain continues to perceive an image for a short period of time after it has disappeared.

As the top spins, the brain perceives the pattern as if it were changing colors due to the persistence of the previous image. This is an optical illusion and the color does not actually change.

Benham's Top
Benham’s Top


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How does Benham’s Top work?

The Benham’s top illusion works by exploiting the phenomenon of persistence of vision. Persistence of vision is a characteristic of the human visual system where an image that is presented for a short period of time is perceived to persist for a fraction of a second longer.

When the Benham’s top is spun, the pattern on the top moves quickly past the viewer’s eyes, and because of persistence of vision, the brain perceives the pattern as if it were changing colors. The pattern on the top is composed of alternating bright and dark colors, and as the top spins, the brain perceives the dark colors as one color and the bright colors as another color, creating the illusion that the top is changing colors.

Additionally, the speed of rotation and the design of the pattern are important factors that affect the illusion. A faster spinning top will make the illusion more pronounced, and a pattern with more distinct colors will be more effective at creating the illusion.

Benham’s top and Fechner color are two different phenomena, but they are related and based on the same principle of persistence of vision.

Benham’s top is a mechanical device that uses a spinning disc with a pattern of alternating bright and dark colors to create the illusion of the disc changing color as it spins. This illusion is created by the brain’s persistence of vision, which makes it perceive the dark and bright colors as different colors.

Fechner color, named after the German psychologist Gustav Fechner, is a similar visual illusion that occurs when a rotating ring with a pattern of alternating colors is viewed. Like Benham’s top, the illusion is created by the brain’s persistence of vision, which makes the viewer perceive the ring as if the colors were blending together.

Both Benham’s top and Fechner color are examples of the persistence of vision phenomenon and how it can create optical illusions.

Versions of the Benham’s Top

The first is the image when still, the second is when it’s spinning:



Benham's Top





Illusions like Benham’s Top

Some related illusions include the following:

A color constancy illusion is a type of visual illusion in which a color appears to be different when viewed in different contexts.

The Checker Shadow Illusion is created by a checkerboard pattern composed of squares with different luminance values, the squares that are not directly illuminated by the light source appear darker than the illuminated squares, creating the illusion of shadows.

Edelson-Checker_shadow_illusion
Checker Shadow Illusion


The simultaneous contrast illusion is a visual effect that occurs when the perception of a color is affected by the colors of the surrounding area.

The illusion creates the appearance of a change in the color of an object, even though the actual color of the object remains constant.


Simultaneous Contrast Effect
The center green dot is the same on both sides, but the surrounding color changes the perception


The Neon Color Spreading illusion refers to the visual phenomenon where an area of color appears to spread or “bleed” beyond its intended boundaries.

Neon Color Spreading
From Wikimedia Commons


The Bezold Effect: This illusion is created by placing two or more colors next to each other, and the way they appear to change when they are close to one another.  

Bezold_Effect
from Wikimedia Commons


The Cornsweet illusion is a classic example of a brightness illusion, which is an illusion in which two areas that are physically the same brightness appear to be different in brightness.

Cornsweet illusion
Cornsweet illusion

The Chubb illusion is based on the perception of brightness and can be observed when a small bright patch is surrounded by a larger dark area, the small bright patch will appear brighter than the same patch surrounded by a bright area.

Chubb Illusion

White’s illusion is a visual phenomenon in which two identical gray bars are placed on a background of alternating black and white stripes.

The gray bars appear to be different shades of gray, with the one on the white stripes appearing lighter than the one on the black stripes.

In the image below, both gray bars have the exact same color.

White's Illusion
White’s Illusion

The Watercolor Illusion: This illusion is created by the way the brain perceives edges of an object. When an object is surrounded by a colored halo, the object appears to have a different color than it actually does.

Watercolor Illusion


The Café Wall Illusion is a visual illusion that is created by a grid of alternating light and dark horizontal and vertical lines. The lines appear to be bent or tilted, even though they are actually straight.

Cafe Wall Illusion


Discovery of Benham’s Top

Benham’s top was discovered by S.G. Benham, a British scientist and inventor in the late 19th century.

He created the top as an optical toy that demonstrated the phenomenon of persistence of vision, and its ability to create the illusion of color change.

He published his work on the top in 1897 in the scientific journal “Nature“. His invention was popularized as a toy and used in demonstrations of optical phenomena in science education and entertainment shows.

References and Resources

Check out our complete list of illusions.

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