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.
In the version below, a straight black and red line is covered by grey rectangle. However, the blue line, not red line, appears to be an extension of the black line. The image on the right reveals the truth.
Table of Contents
- How does the Poggendorff Illusion work?
- Versions of the Poggendorff Illusion
- Illusions like the Poggendorff Illusion
- Discovery of the Poggendorff Illusion
- References and Resources
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How does the Poggendorff Illusion work?
The Poggendorff illusion works by the brain interpreting the misalignment of two parallel lines that are intersected by a third line at a certain angle as a gap or interruption in the diagonal line, even though the line is actually continuous. It is thought that the brain interprets the misalignment as an occlusion, or an object blocking the diagonal line, which causes the illusion.
The exact neural mechanisms that underlie the Poggendorff illusion are not well understood, but it is thought that the brain’s tendency to group similar elements together, known as gestalt grouping, plays a role. Additionally, the brain’s tendency to perceive lines and edges as continuing behind occluding objects may also contribute to the illusion.
Overall, the Poggendorff illusion demonstrate that visual perception is an active process that is influenced by both the physical properties of the stimulus and the brain’s assumptions about the scene.
The illusion was first described by the German physicist Johann Poggendorff in 1860. It is often used in research on perception and cognitive psychology to study the way the brain processes visual information.
Versions of the Poggendorff Illusion
The following are some alternate versions of the Poggendorff Illusion
Illusions like the Poggendorff Illusion
The Poggendorff illusion is a type of size-distance illusions, also known as size contrast illusions, which are visual illusions in which the size or distance of an object is perceived differently than it actually is. These illusions are caused by the way the brain processes visual information and the surrounding context. Some examples of size-distance illusions include:
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 Delboeuf Illusion: This illusion involves the perception of circles of different sizes appearing to be the same size when they are surrounded by other circles of different sizes.
The Zöllner illusion: A another size-contrast illusion in which a group of diagonal lines appear to be distorted or bent due to the presence of intersecting lines. This illusion involves the perception of diagonal lines that appear to be bent or tilted, even though they are actually straight.
The Müller-Lyer illusion is a classic example of size-contrast illusion, in which two lines of equal length appear to be different due to the presence of arrowheads or fins at the end of the lines.
Moon illusion: This illusion involves the perception of the Moon appearing larger when it is near the horizon compared to when it is high in the sky.
Ponzo illusion: This illusion involves the perception of an object appearing larger or smaller depending on the size of the surrounding context.
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.
Münsterberg illusion: A special version of the Café Wall Illusion. This illusion involving the perception of the size of an object appearing to change when the surrounding context changes.
These illusions show that the brain’s perception of size and distance can be influenced by the surrounding context, and that the visual information the brain receives is not always an accurate representation of reality.
Discovery of the Poggendorff Illusion
The illusion was first described by the German physicist Johann Poggendorff in 1860. It is often used in research on perception and cognitive psychology to study the way the brain processes visual information.
Johann Christian Poggendorff was a German physicist, mathematician and inventor. He is best known for his work in the field of electricity and magnetism, and for his invention of the Poggendorff Illusion. He was born in 1796 in Hamburg, Germany and died in 1877 in Berlin, Germany.
Poggendorff studied mathematics and physics at the University of Berlin and later worked as a professor of physics at the University of Breslau. He made significant contributions to the field of electricity and magnetism, including the invention of the Poggendorff Illusion in 1860. He also developed the Poggendorff’s circle, a mathematical construct used to represent the intersection of two circles in a plane.
Poggendorff was also a member of several scientific societies and was awarded several honors for his work, including the Copley Medal of the Royal Society of London in 1878. He is also remembered for his contributions to the field of science through the Poggendorff’s Annalen der Physik und Chemie, which he founded and edited for many years.
References and Resources
Check out our complete list of illusions.