Schroeder stairs (Schröder's stairs) is an
optical illusion
In visual perception, an optical illusion (also called a visual illusion) is an illusion caused by the visual system and characterized by a visual perception, percept that arguably appears to differ from reality. Illusions come in a wide varie ...
which is a two-dimensional drawing which may be perceived either as a drawing of a staircase leading from left to right downwards or the same staircase only turned upside down, a classical example of
perspective reversal
Perspective may refer to:
Vision and mathematics
* Perspectivity, the formation of an image in a picture plane of a scene viewed from a fixed point, and its modeling in geometry
** Perspective (graphical), representing the effects of visual persp ...
in psychology of perception. It is named after the German
natural scientist
Natural science or empirical science is one of the branches of science concerned with the description, understanding and prediction of natural phenomena, based on empirical evidence from observation and experimentation. Mechanisms such as peer ...
Heinrich G. F. Schröder, who published it in 1858.
[Alwyn Scott, ''Stairway to the Mind: The Controversial New Science of Consciousness'']
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It is sometimes called "Schouten steps",[ in reference to a small sheet-metal staircase given to ]M. C. Escher
Maurits Cornelis Escher (; ; 17 June 1898 – 27 March 1972) was a Dutch graphic artist who made woodcuts, lithography, lithographs, and mezzotints, many of which were Mathematics and art, inspired by mathematics.
Despite wide popular int ...
by Prof. Schouten and which was an inspiration for Escher's '' Convex and Concave''. This illusion is also seen in another Escher's work, '' Relativity''.[ Barile, Margherita. ]
Schroeder Stairs
', from Eric W. Weisstein's MathWorld
''MathWorld'' is an online mathematics reference work, created and largely written by Eric W. Weisstein. It is sponsored by and licensed to Wolfram Research, Inc. and was partially funded by the National Science Foundation's National Science ...
This drawing may be variously described as an "ambiguous figure
Ambiguous images or reversible figures are visual forms that create ambiguity by exploiting graphical similarities and other properties of visual system interpretation between two or more distinct image forms. These are famous for inducing the ...
", "reversible figure
Ambiguous images or reversible figures are visual forms that create ambiguity by exploiting graphical similarities and other properties of visual system interpretation between two or more distinct image forms. These are famous for inducing the ...
" or " bistable figure". The first classification refers to the likelihood that the drawing may be perceived as two (or more) different objects. The second refers to the phenomenon that after some time of staring at the figure the perception of its orientation becomes involuntarily reversed.[ The third one emphasizes the fact that there are two (rather than one) stable perceptions of the drawing.][''Nonlinear Dynamics in the Life and Social Sciences'', edited by William H. Sulis, Irina Nikolaevna Trofimova]
p. 315
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This illusion, among others, has been used in studies of perception. In particular, in one study it was established that involuntary switch of perception occurs with approximate frequency of once in 7.5-12.5 seconds. The change of perception may be attributed either to neuronal fatigue or to conscious selection.[As cited in ''Nonlinear Dynamics...'']
References
{{DEFAULTSORT:Schroeder Stairs
Optical illusions
Stairways