View source for Form constant

{{More citations needed|date=January 2022}}
{{short description|Recurringly observed geometric pattern}}
[[File:Form constant.jpg|right|thumb|300px|An example of a form constant]]
A '''form constant''' is one of several [[Pattern|geometric pattern]]s which are recurringly observed during [[hypnagogia]], [[hallucination]]s and [[altered states of consciousness]].

==History==
[[File:Klüver's Form Constants.jpg|thumb|Klüver's four form constants]]
In 1926, [[Heinrich Klüver]] systematically studied the effects of [[mescaline]] ([[peyote]]) on the [[subjective experience]]s of its users. In addition to producing hallucinations characterized by bright, "highly [[Saturation (color theory)|saturated]]" colors and vivid imagery, Klüver noticed that mescaline produced recurring [[geometric pattern]]s in different users. He called these patterns "form constants" and categorized four types: [[lattice (group)|lattices]] (including [[Hexagonal lattice|honeycomb]]s, [[checkerboard]]s, and [[triangle]]s), [[Spider web|cobweb]]s, tunnels, and [[spiral]]s.<ref name="Bressloff2002">{{cite journal | last = [[Paul Bressloff|Bressloff]] | first = Paul C. |author2=Cowan, Jack D. |author3=Golubitsky, Martin |author4=Thomas, Peter J. |author5=Weiner, Matthew C. |date=March 2002 | title = What Geometric Visual Hallucinations Tell Us About the Visual Cortex | journal = Neural Computation | volume = 14 | issue = 3 | pages = 473–491 | doi = 10.1162/089976602317250861 | pmid = 11860679| citeseerx = 10.1.1.146.572 | s2cid = 207683037 }}</ref>

In 1988 [[David Lewis-Williams]] and T.A. Dowson incorporated the form constant into his [[Entoptic phenomena (archaeology)#David Lewis-Williams's system|Three Stages of Trance model]], the geometric shapes comprising the visuals observed in the model's first stage.

==Precipitants==
Klüver's form constants have appeared in other drug-induced and naturally occurring hallucinations, suggesting a similar physiological process underlying hallucinations with different triggers. Klüver's form constants also appear in [[near-death experience]]s and sensory experiences of those with [[synesthesia]]. Other triggers include [[psychological stress]], [[hypnagogia|threshold consciousness (hypnagogia)]], [[insulin hypoglycemia]], the delirium of [[fever]], [[epilepsy]], [[psychosis|psychotic episodes]], advanced [[syphilis]], [[sensory deprivation]], [[photostimulation]], [[electrical stimulation]], [[crystal gazing]], migraine headaches, [[dizziness]] and a variety of [[drug]]-induced [[Substance intoxication|intoxication]]s.<ref name="Bressloff2002" /> These shapes may appear on their own or with eyes shut in the form of [[phosphene]]s, especially when exerting pressure against the closed eyelid.<ref>{{cite journal|last1=Tyler|first1=CW|title=Some new entoptic phenomena.|journal=Vision Research|date=1978|volume=18|issue=12|pages=1633–9|doi=10.1016/0042-6989(78)90255-9|pmid=726316|s2cid=30888279 }}</ref>

It is believed that the reason why these form constants appear has to do with the way the visual system is organized, and in particular in the mapping between patterns on the [[retina]] and the columnar organization of the [[Visual_cortex#Primary_visual_cortex_(V1)|primary visual cortex]]. Concentric circles in the retina are mapped into parallel lines in the visual cortex. Spirals, tunnels, lattices and cobwebs map into lines in different directions. This means that if activation spreads in straight lines within the visual cortex, the experience is equivalent to looking at actual form constants.<ref name="Bressloff2002" />

Author [[Michael Moorcock]] once observed in print that the shapes he had seen during his [[migraine headache]]s resembled exactly the form of [[fractal]]s. The diversity of conditions that provoke such patterns suggests that form constants reflect some fundamental property of [[visual perception]].

==Cultural significance==

Form constants have a relationship to some forms of [[abstract art]], especially the [[visual music]] tradition, as [[William Wees]] noted in his book ''Light Moving in Time'' about research done by German psychologist Heinrich Klüver on the form constants resulting from mescaline intoxication. The visual and synaesthetic hallucinations this drug produced resembles, as Wees noted, a listing of visual forms employed in visual music:

{{blockquote|[Klüver’s] analysis of hallucinatory phenomena appearing chiefly during the first stages of mescaline intoxication yielded the following form constants:  [emphasis original] (a) grating, lattice, fretwork, filigree, honeycomb, or chessboard; (b) cobweb; (c) tunnel, funnel, alley, cone or vessel; (d) spiral. Many phenomena are, on close examination, nothing but modifications and transformations of these basic forms. The tendency towards "geometrization," as expressed in these form constants, is also apparent in the following two ways: (a) the forms are frequently repeated, combined, or elaborated into ornamental designs and mosaics of various kinds; (b) the elements constituting these forms, such as squares in the chessboard design, often have boundaries consisting of geometric forms.<ref>Wees, William C. Light Moving in Time: Studies in the Visual Aesthetics of Avant-Garde Film, (Berkeley: University of California Press, 1992), p. 66.</ref>}}

These form-constants provide links between abstraction, visual music and synaesthesia. The cultural significance of form constants, as Wees notes in ''Light Moving in Time'' is part of the history of abstract film and video.

The practice of the ancient art of [[divination]] may suggest a deliberate practice of cultivating form constant imagery and using [[Intuition (knowledge)|intuition]] and/or imagination to derive some meaning from transient visual phenomena.

[[Psychedelic art]], inspired at least in part by experiences with psychedelic substances, frequently includes repetitive abstract forms and patterns such as [[tessellation]], [[Moiré pattern]]s or patterns similar to those created by [[paper marbling]], and, in later years, [[fractal]]s. The [[op art]] genre of visual art created art using bold imagery very like that of form constants.

In [[electroacoustic music]], Jon Weinel has explored the use of altered states of consciousness as a basis for the design of musical compositions.  His work bases the design of sonic materials on typical features of hallucinatory states, and organises them according to hallucinatory narratives.  As part of this work, form constants feature prominently as a basis for the design of psychedelic sonic and visual material.<ref>Weinel, J. [http://www.jonweinel.com/PDF/Weinel_2013_AM13_Visual_Patterns.pdf "Visual patterns of hallucination as a basis for sonic arts composition"].  ''Proceedings of Audio Mostly 2013''.</ref>

==See also==
{{div col}}
*[[Biosemiotics]]
*{{annotated link|Closed-eye hallucination}}
*{{annotated link|Entoptic phenomenon}}
*{{annotated link|Hypnagogia}}
*{{annotated link|Kaleidoscope}}
*{{annotated link|Mandala}}
*{{annotated link|Paisley (design)}}
*{{annotated link|Pattern recognition}}
*{{annotated link|Psychophysics}}
*{{annotated link|Qualia}}
*{{annotated link|Religion and drugs}}
*{{annotated link|Visual cortex}}
*{{annotated link|Visual snow}}
*{{annotated link|Visual system}}
*{{annotated link|Uniform tilings in hyperbolic plane}}
{{div col end}}

==References==
{{reflist}}

==Sources==
{{refbegin}}
*[[Susan Blackmore|Blackmore, Susan]]. Dying to Live: Near-Death Experiences. Buffalo, NY: Prometheus Books, 1993.
*[[Richard Cytowic|Cytowic, Richard E.]], [[The Man Who Tasted Shapes]].
*Ermentrout, G.B. and  Cowan, J.D., "A mathematical theory of visual hallucination patterns."  ''Biol. Cybernet.'' 34 (1979), no. 3, 137–150.
{{refend}}

==External links==
*[http://www.entheology.org/edoto/anmviewer.asp?a=165 Text from "Hallucinogens and Creativity" page by Susan Opar]
*[https://archive.org/details/redwood_center_2006_02_14_cowan "Spontaneous pattern formation in large scale brain activity: what visual migraines and hallucinations tell us about the brain"; online video of lecture by Jack Cowan]
*[http://www.math.utah.edu/~bresslof/publications/Colston.pdf "Spontaneous pattern formation in the primary visual cortex"]
* [http://www.math.utah.edu/~bresslof/publications/01-3.pdf free version of "What Geometric Visual Hallucinations Tell Us about the Visual Cortex"]
{{Visual phenomena}}

{{DEFAULTSORT:Form Constant}}
[[Category:Hallucinations]]
[[Category:Symptoms and signs of mental disorders]]
[[Category:Psychedelia]]
[[Category:Divination]]
[[Category:Visual motifs]]
[[Category:Psychedelic drug research]]
[[Category:Vision]]