Editing Multistable perception

{{Short description|Perceptual phenomenon}}
[[Image:Optical Illustion-Ambiguous Patterns.svg|frame|Examples of visually ambiguous patterns. From top to bottom: [[Necker cube]], [[Schroeder stairs]] and a figure that can be interpreted as black or white arrows.]]

'''Multistable perception''' (or '''bistable perception''') is a [[perceptual]] phenomenon in which an observer experiences an unpredictable sequence of spontaneous subjective changes. While usually associated with [[visual perception]] (a form of [[optical illusion]]), multistable perception can also be experienced with [[Sound|auditory]] and [[olfactory]] percepts.

== Classification ==
Perceptual [[multistability]] can be evoked by visual patterns that are too [[ambiguous]] for the human [[visual system]] to definitively and uniquely interpret. Familiar examples include the [[Necker cube]], [[Schroeder staircase]], [[structure from motion]], [[monocular rivalry]], and [[binocular rivalry]], but many more visually [[ambiguous image|ambiguous patterns]] are known. Because most of these images lead to an alternation between two mutually exclusive perceptual states, they are sometimes also referred to as bistable perception.<ref>{{cite journal | last = Eagleman | first = D. | title = Visual Illusions and Neurobiology | journal = Nature Reviews Neuroscience | year = 2001 | volume = 2 | issue = 12 | pages = 920–926 | url = http://neuro.bcm.edu/eagleman/papers/Eagleman.NatureRevNeuro.Illusions.pdf | doi = 10.1038/35104092 | pmid = 11733799 | s2cid = 205023280 | url-status = dead | archiveurl = https://web.archive.org/web/20070927212714/http://neuro.bcm.edu/eagleman/papers/Eagleman.NatureRevNeuro.Illusions.pdf | archivedate = 2007-09-27 }}</ref>

[[multistable auditory perception|Auditory]] and [[olfactory]] examples can occur when there are conflicting, and so rival, inputs into the two [[ear]]s<ref>{{ cite journal |
author = Deutsch, D. | year = 1974 | title = An Auditory Illusion | journal = Nature | volume = 251 | issue = 5473 | pages = 307–309 | doi = 10.1038/251307a0 | pmid = 4427654 | s2cid = 4273134 }}</ref> or two [[nostril]]s.<ref>{{ cite journal |author1=Zhou, W. |author2=Chen, D. | year = 2009 | title =  Binaral Rivalry Between the Nostrils and in the Cortex | journal = Current Biology | volume = 19 | issue = 18 | pages = 1561–1565 | doi = 10.1016/j.cub.2009.07.052 | pmid = 19699095 | pmc=2901510}}</ref>

== Characterization ==
The transition from one precept (an undefined term) to its alternative (the defined term) is called a perceptual reversal ([[Paradigm shift]]). They are spontaneous and [[stochastic]] events that cannot be eliminated by intentional efforts, although some control over the alternation process is learnable. Reversal rates vary drastically between stimuli and observers. They are slower for people with [[bipolar disorder]].<ref>{{Cite journal | last1 = Pettigrew | first1 = J. D. | last2 = Miller | first2 = S. M. | doi = 10.1098/rspb.1998.0551 | title = A 'sticky' interhemispheric switch in bipolar disorder? | journal = Proceedings of the Royal Society B: Biological Sciences | volume = 265 | issue = 1411 | pages = 2141–2148 | year = 1998 | pmid = 9872002 | pmc =1689515 }}</ref><ref>{{cite journal | url = http://www.uq.edu.au/nuq/jack/PsychMed.pdf | title = Slow Binocular Rivalry in Bipolar Disorder | last = Miller | first = S. M. | author2 = Gynther, B. D. | author3 = Heslop, K. R. | author4 = Liu G. B. | author5 = Mitchell, P. B. | author6 = Ngo, T. T. | author7 = Pettigrew, J. D. | author8 = Geffen, L. B. | journal = Psychological Medicine | year = 2003 | volume = 33 | issue = 4 | pages = 683–692 | doi = 10.1017/S0033291703007475 | pmid = 12785470 | citeseerx = 10.1.1.693.9166 | s2cid = 30727987 | access-date = 2006-09-24 | archive-date = 2018-10-03 | archive-url = https://web.archive.org/web/20181003155825/http://www.uq.edu.au/nuq/jack/PsychMed.pdf | url-status = dead }}</ref>

== Cultural history ==
Human interest in these phenomena can be traced back to [[Ancient history|antiquity]].{{Citation needed|date=November 2020}} The fascination with multistable perception probably comes from the active nature of [[endogenous]] perceptual changes or from the dissociation of dynamic perception from constant sensory stimulation. 

Multistable perception was a common feature in the artwork of the [[Netherlands|Dutch]] [[lithography|lithographer]] [[M. C. Escher]], who was strongly influenced by mathematical physicists such as [[Roger Penrose]].{{Citation needed|date=May 2018}}

== Examples ==
=== Real-world phenomena ===
Photographs of craters, from either the moon or other planets including our own, can exhibit this phenomenon. Craters in stereo vision, such as our eyes, normally appear concave. However, in monocular presentations, such as photographs, the elimination of our depth perception causes multistable perception, which can cause the craters to look like plateaus rather than pits. For humans, the "default" interpretation comes from an assumption of [[top-left lighting]], so that rotating the image by 180 degrees can cause the perception to suddenly switch.<ref>{{cite web |title=A lunar illusion you'll flip over |url=https://www.discovermagazine.com/the-sciences/a-lunar-illusion-youll-flip-over |website=Discover Magazine |language=en}}</ref><ref>{{cite web |author1=Minutephysics |title=The "Mountain Or Valley?" Illusion |url=https://www.youtube.com/watch?v=V7C318DGB38  |archive-url=https://ghostarchive.org/varchive/youtube/20211212/V7C318DGB38| archive-date=2021-12-12 |url-status=live|website=YouTube |date=29 June 2017}}{{cbignore}}</ref> This phenomenon is called the concave/convex, or simply up/down, ambiguity, and it confuses [[computer vision]] as well.<ref>{{cite book |doi=10.3217/978-3-85125-603-1-13 |year=2018 |last1=Breuß |first1=Michael |last2=Mansouri |first2=Ashkan |last3=Cunningham |first3=Douglas |chapter=The Convex-Concave Ambiguity in Perspective Shape from Shading |title=Proceedings of the OAGM Workshop 2018 |isbn=978-3-85125-603-1 }}</ref>

=== In popular culture ===
In literature, the [[science fiction]] [[novel]], ''[[Dhalgren]]'', by [[Samuel R. Delany]], contains circular text, multistable perception, and multiple entry points.{{fact|date=October 2019}}

Multistable perception arises with the theater segments of ''[[Mystery Science Theater 3000]]'', as due to the construction of the [[Crow T. Robot]] puppet, its head can appear to be facing towards the camera rather than towards the film being shown. This was addressed by the creators of the series, even likening Crow to a [[Necker cube]]<ref name="necker">{{Cite book | author-link = Best Brains | year = 1996 | title = The Mystery Science Theater 3000 Amazing Colossal Episode Guide |page = 159 | publisher = Bantam | isbn = 978-0-553-37783-5 | author = Trace Beaulieu ... }}</ref> or [[The Spinning Dancer]].{{when|date=October 2019}}

== See also ==
* [[Cognitive neuroscience]]
* [[Experimental psychology]]
* [[Gestalt psychology]]
* [[Op art]]
* [[Salvador Dalí]]

==Bibliography==
* {{ cite book |editor1=Alais, D |editor2=Blake, R. | title = Binocular Rivalry | publisher =  MIT Press | year = 2005 | isbn = 978-0-262-01212-6 }}
* {{ cite book |author1=Kruse, P. |author2=Stadler, M. | title = Multistable Cognitive Phenomena | publisher = Springer | year = 1995 | isbn = 978-0-387-57082-2 }}

==Sources==
{{reflist}}

==External links==
* [http://www.visualfunhouse.com/ VisualFunHouse Optical Illusions] Multistable perception Optical Illusions
* [https://web.archive.org/web/20030806084943/http://eluzions.com/Illusions/Ambiguous/ A collection of visually ambiguous patterns]
* {{cite journal | author1 = Miller, S. M. | author2 = Liu, G. B. | author3 = Ngo, T. T. | author4 = Hooper, G. | author5 = Riek, S. | author6 = Carson, R. G. | author7 = Pettigrew, J. D. | url = http://www.uq.edu.au/nuq/jack/HTMLCBpaper.htm | title = Interhemispheric Switching Mediates Perceptual Rivalry | journal = Current Biology | year = 2000 | volume = 10 | issue = 7 | pages = 383–392 | pmid = 10753744 | doi = 10.1016/S0960-9822(00)00416-4 | s2cid = 51808719 | doi-access = free | access-date = 2006-01-21 | archive-date = 2021-02-11 | archive-url = https://web.archive.org/web/20210211042643/http://www.uq.edu.au/nuq/jack/HTMLCBpaper.htm | url-status = dead }}
* [http://figuresambigues.free.fr/SommairesJeux/modemploienglish.html Ambiguous figures] Ambiguity of spatial perception (fr)
{{Sensation and perception}}

[[Category:Perception]]
[[Category:Optical illusions]]