Jastrow illusion

Identical toy railway tracks as a real example of a Jastrow illusion

The Jastrow illusion is an optical illusion attributed to the Polish-American psychologist Joseph Jastrow.[1] This optical illusion is known under different names: Ring-Segment illusion, Jastrow illusion, Wundt area illusion or Wundt-Jastrow illusion.[2]

The illusion also occurs in the real world. The two toy railway tracks pictured are identical, although the lower one appears to be larger. There are three competing theories on how this illusion occurs.[2]

This illusion is often included in magic kits and several versions are sold in magic shops and is commonly known under the name Boomerang Illusion.[3]

Wikimedia Commons has media related to Jastrow illusion.
  1. ^ Jastrow, Joseph (1892-01-01). "Studies from the Laboratory of Experimental Psychology of the University of Wisconsin. II". The American Journal of Psychology. 4 (3): 381–428. doi:10.2307/1411617. JSTOR 1411617.
  2. ^ a b Tronick, Edward; Hershenson, Maurice (1979-02-01). "Size-distance perception in preschool children". Journal of Experimental Child Psychology. 27 (1): 166–184. doi:10.1016/0022-0965(79)90068-7. PMID 458369.
  3. ^ Prevos, Peter. "The Jastrow Illusion in Magic". Archived from the original on 2016-05-16. Retrieved 2016-07-16.