Zollner illusion
Encyclopedia
The Zöllner illusion is a classic optical illusion
named after its discoverer, German astrophysicist Johann Karl Friedrich Zöllner
. In 1860, Zöllner sent his discovery in a letter to physicist and scholar Johann Christian Poggendorff
, editor of Annalen der Physik und Chemie
, who subsequently discovered the related Poggendorff illusion
, in the original drawing (Table VIII Figure 4) of Zöllner.
In this figure the black lines seem to be unparallel, but in reality they are parallel. The shorter lines are on an angle to the longer lines. This angle helps to create the impression that one end of the longer lines is nearer to the viewer than the other end. This is very similar to the way the Wundt illusion
appears. It may be that the Zöllner illusion is caused by this impression of depth.
If the illusion is printed in green on a red background and the red and green are equally bright, the illusion disappears.
This illusion is similar to the Hering illusion
, the Poggendorff illusion
and the Müller-Lyer illusion. All these illusions demonstrate how lines can seem to be distorted by their background.
Optical illusion
An optical illusion is characterized by visually perceived images that differ from objective reality. The information gathered by the eye is processed in the brain to give a perception that does not tally with a physical measurement of the stimulus source...
named after its discoverer, German astrophysicist Johann Karl Friedrich Zöllner
Johann Karl Friedrich Zöllner
Johann Karl Friedrich Zöllner was a German astrophysicist who studied optical illusions. He invented the Zöllner illusion where lines that are parallel appear diagonal. The lunar Zöllner crater is named in his honor...
. In 1860, Zöllner sent his discovery in a letter to physicist and scholar Johann Christian Poggendorff
Johann Christian Poggendorff
Johann Christian Poggendorff , was a German physicist born in Hamburg.By far the greater and more important part of his work related to electricity and magnetism. Poggendorff is known for his electrostatic motor which is analogous to Wilhelm Holtz's electrostatic machine...
, editor of Annalen der Physik und Chemie
Annalen der Physik
Annalen der Physik is one of the oldest physics journals worldwide. The journal publishes original, peer-reviewed papers in the areas of experimental, theoretical, applied and mathematical physics and related areas...
, who subsequently discovered the related Poggendorff illusion
Poggendorff illusion
The Poggendorff Illusion is a geometrical-optical illusion that involves the misperception of the position of one segment of a transverse line that has been interrupted by the contour of an intervening structure...
, in the original drawing (Table VIII Figure 4) of Zöllner.
In this figure the black lines seem to be unparallel, but in reality they are parallel. The shorter lines are on an angle to the longer lines. This angle helps to create the impression that one end of the longer lines is nearer to the viewer than the other end. This is very similar to the way the Wundt illusion
Wundt illusion
The Wundt illusion is an optical illusion that was first described by the German psychologist Wilhelm Wundt in the 19th century. The two red vertical lines are both straight, but they may look as if they are bowed inwards to some observers. The distortion is induced by the crooked lines on the...
appears. It may be that the Zöllner illusion is caused by this impression of depth.
If the illusion is printed in green on a red background and the red and green are equally bright, the illusion disappears.
This illusion is similar to the Hering illusion
Hering illusion
The Hering illusion is a one of the geometrical-optical illusions and was discovered by the German physiologist Ewald Hering in 1861 . Two straight and parallel lines look as if they were bowed outwards. The distortion is produced by the radiating pattern and was ascribed by Hering to an...
, the Poggendorff illusion
Poggendorff illusion
The Poggendorff Illusion is a geometrical-optical illusion that involves the misperception of the position of one segment of a transverse line that has been interrupted by the contour of an intervening structure...
and the Müller-Lyer illusion. All these illusions demonstrate how lines can seem to be distorted by their background.
External links
- Zöllner illusion at Akiyoshi Kitayoka's illusion pages