The Origins of Human Art and Symbolism: Entoptic Phenomena and the Neurocognitive Model.

Designs that are found universally and thought to originate or be inspired by naturally-occuring visual effects within the eye. (Source:

Designs that are found universally and thought to originate or be inspired by naturally-occuring visual effects within the eye. (Source:

Entoptic visuals are a physiological effect that can be produced naturally in the visual processing center of any human. Not to be confused with optical illusions, they are visual sensations produced by mechanisms within the eye, namely in relation to the retina and under certain conditions.

Representation of “floaters”, caused by vitreous coagulations in the eye. (Source:

They often occur in linear zig-zag patterns, dots, and other abstract shapes, and can be caused by mechanisms including the movement of white blood cells in capillaries in front of the retina or floating coagulations of vitreous jelly within the eye. Other shapes produced by these documented phenomena include hourglass or bow-tie shapes, arcs, squiggly lines, and the “Purkinje Tree”, which is a visual imprint of the blood vessels within one’s own eye that can be seen when light shines into the pupil from an opportune angle. One can also produce a phosphene, or the perception of light and veiny or zig-zag-like lines by applying pressure to the closed eye.[2]

Most of these phenomena are caused by the viewing of a plain, solid background such as a clear sky. Needless to say, the phenomena could easily be encountered in daily life when outdoors. Another interesting phosphene-related visual phenomenon called “Prisoner’s Cinema” is known to occur when one is confined in darkness for extended periods of time. It presents as a “light show” in the darkness that can be amorphous but eventually takes familiar human or animal forms. It has commonly been noted by people practicing intense meditation or activities requiring long-term mental focus, such as pilots, astronauts, and truck drivers.[6] It is easy to imagine how the conditions of life in a cave might produce this effect, and the possible connection to cave art has been noted by researchers.[5] It is certainly reminiscent of some more abstract cave art forms, such as Chauvet Cave’s pointillism-style bison discussed in my post on hand motifs. More interestingly, all of the described entoptic phenomena thus far are also known to be produced by the brain during epileptic fits, migraines, and altered states of consciousness.[1]

Other researchers have studied art produced by schizophrenic patients and found striking similarities to entoptic figures. This has been linked to another type of entoptic imagery, called a ‘form-constant,’ thought to be produced in the visual cortex. These images are often geometric in style and linked to the nervous system. The “viewer” might associate them or mentally connect them with a familiar image or pattern, in which case they’re considered visual hallucinations. This type of entoptic imagery is often noted during altered states produced by use of entheogens or “natural” trance states induced by behaviors such as meditation and fasting.[8] It is also seen in schizophrenics.[7]

Entoptic imagery and schizophrenics: image from study by M. J. Horowitz, 1964.

Entoptic imagery and schizophrenics: image from study by M. J. Horowitz, 1964.

Research into entoptic visuals caused by mental imbalances and entheogens has shown that certain structural similarities found in entoptic imagery are experienced by many different individuals and through many different methods of induction. These similar visuals, or ‘form-constants’, were shown in 1964 in a study by M.J. Horowitz.[7]


Close-up of common entoptic-like cave designs. (Source:

The striking similarity of many of these entoptic images to humanity’s earliest-known symbolic imagery and geometric designs has caught the attention of a number of neurocognitive researchers. These researchers have incorporated them into a cognitive neurological framework that places entoptics and several other cognitive mechanisms at the critical juncture of humanity’s first verified demonstration of symbolic practice. That is, these designs “came first,” so to speak, physiologically and later were given symbolic meaning and totemic functions within a social system.[1] They might also be associated with the rise of early animistic belief or possibly shamanistic behaviors associated with hallucination and trance states, as seen in a number of documented cultures globally.[8]

Evidence for this physiological origin includes the prominence of classic entoptic designs such as nested curves, cross-hatching, dots, and zig-zag patterns in the earliest known forms of human symbolic expression separate from self-adornment– for example, the incised ochre blocks at Blombos Cave from the Middle Stone Age, dated to approximately 100,000 BC and discussed in more detail in my previous post. These are humanity’s earliest known symbolic objects. They’re also accompanied by similarly-decorated objects found at other cave sites in South Africa that seemed to appear around that geographic area in the same period.[2][3]

The developmental timeframes of the sociocognitive and physiological structures necessary to make these connections are unknown and will never truly be known. However, it is likely that, given the slow pace of evolutionary change in our brains and bodies, Homo sapiens‘ transition toward symbolic behavior (assuming the validity of the neurocognitive model) developed gradually over time rather than in an abrupt or “revolutionary” way. It seems possible that human cognitive complexity and symbolic behavior began even before the Middle Stone Age, but that material evidence for it either was subject to differential preservation outside of caves or hasn’t yet been found.

The following videos describe the history and science behind entoptic phenomena, as well as how to produce them yourself!


1. Morriss-Kay, Gillian M. 2010. The evolution of human artistic creativity. Journal of Anatomy, 216, 158-176.

2. Balter, M. 2009a. Early start for human art? Ochre may revise timeline.

3. Balter, M. 2009b. On the Origin of Art and Symbolism. Science, 323, 709-711.


5. Murchie, Guy. 1998. The Seven Mysteries of Life: An Exploration in Science and Philosophy. Houghton Mifflin Harcourt. p. 237. ISBN 0-395-95791-5.




Early symbolic behavior: Blombos Cave, South Africa

Blombos Cave, South Africa. (Source:

Blombos Cave is a South African coastal site located 300 KM east of Cape Town. It is currently the oldest known site containing solid evidence of symbolic thinking and behavior by Homo sapiens, with its earliest faunal and archaeological deposits dated to the Middle Stone Age period between 100,000-70,000 BC.[1][2][3]
Though the site has been in the process of excavation since 1991, it has been more recent findings at the site that have fundamentally changed our perspectives on the appearance and origins of abstract reasoning and capabilities.

Stratigraphy at Blombos Cave. (Source:

The importance of findings at this site cannot be underestimated. Archaeologists at Blombos Cave first rocked the discipline in 2002 after finding several pieces of geometrically-incised ochre dating to 77,000 BP, calling into doubt the prevailing idea that symbolic behavior and artistic innovation was part of a “revolution” that didn’t really occur until around 40,000 BP in Europe. Archaeologists found further evidence of symbolic thinking and possibly artistic tradition when they recovered 13 more engraved ochre pieces dated to 100,000 BP, removing any doubt about the previous discovery.[1] It is thought that this material was used in powder form as body paint, a fundamental and early human symbolic behavior extensively recorded in Europe as well. [5] Whether this body paint had practical or more social purposes is unknown.

Bone tools found at Blombos Cave, Middle Stone Age phase. (Source: Wikipedia)

Artifacts associated with an ochre processing “kit” dated to the Middle Stone Age. (Source: flickering

In order to tease out distinctions of practical use vs. symbolic use, discovering archaeologists Henshilwood and Mellars analyzed the pattern types and microscopically examined the incised designs, concluding that they had been made very intentionally in controlled circumstances. The incisions were consistent with the use of a specialized pointed stone tool and indicating some purpose other than powder grinding. Later excavations have found evidence of an “ochre workshop,” demonstrating the importance of these symbolic behaviors within the community.[3] Their meaning is not subject to speculation, but the geometric incised designs are consistent with those found at other Middle Stone Age sites, such as Wonderwerk cave and Klasies River cave. In addition to ochre artifacts, archaeologists also recovered bone tools, incised bone, a cluster of 24 perforated Nassarius Karussianus shell beads likely used for self-adornment, and retouched bifacial points. [6]

Incised ochre from Blombos Cave, dated to the Middle Stone Age. (Source:

Neurocognitive scientists associate these sorts of designs with the development of cognitive structures required for symbolic association and artistic tradition.[5] The findings at these caves have produced a paradigm shift in our understanding of the temporal and geographic origins of human artistic capabilities. It was long thought that this capability emerged in Europe at around 40,000 BC; however, this eurocentric notion has been upended.


1. Balter, M. 2009a. Early start for human art? Ochre may revise timeline.

2. Balter, M. 2009b. On the Origin of Art and Symbolism. Science, 323, 709-711

3. Henshilwood, Christopher S., et al. 2011. A 100,000-Year-Old Ochre-Processing Workshop at Blombos Cave, South Africa. Science, 334, 219-222.

4. Henshilwood, Christopher S. & d’Errico, Francesco. 2011. Homo symbolicus: the dawn of language, imagination and spirituality, Amsterdam ; Philadelphia, John Benjamins Pub. Co

5. Morriss-Kay, Gillian M. 2010. The evolution of human artistic creativity. Journal of Anatomy, 216, 158-176.