Tuesday, July 10, 2012

Cultural Evolution of Basic Color Terms

Time for some explanation.

This is perhaps the most important diagram I have ever seen regarding "Color Theory",
Durham’s example of genetic mediation in the cultural fitness of a set of memes (pp213-218).

The genotypes considered are those responsible for the pigment-based system of light absorption in the eye, and the neurophysiological processing of sensory input to the brain.

1969: anthropologists Brent Berlin and Paul Kay undertook an experiment to prove the semantic relativity of language across different cultures. They wanted to prove that each culture divides the spectral continuum arbitrarily. (But their data, re-examined, proves something much more impactful.)

Native speakers of 20 different languages were asked to
1. List the color terms in their language
2. Pick a ‘focal point’ (the most typical example acceptable) for each of those color terms out of a 329-color palette.
3. Outline the outer boundary (on the color palette) of acceptable colors for that term.

The data shows a tight clustering around what we can now call the eleven universal colors.

“There appears to be a fixed sequence of evolutionary stages through which a language must pass as its basic color vocabulary increases.”  (Berlin and Kay, p14)

“Black, white, red, green, yellow, blue are the six primaries, once they are encoded, the other colors can be combined from the basics.” (Kay and McDaniel)

If a language encodes fewer than 11 basic colors, there are strict limitations, as follows. All languages have names for black and white (which are more like opposites; either dark/light or warm/cool), so we begin with every language having at least 2 color names. If the language has 3 color names, then red is always the third color...

2-black and white
4-green or yellow
5-green and yellow
8+purple, pink, orange, grey

-Basic color terms are a specific kind of meme with considerable cross-cultural regularity.
-Compared to other descriptions of color, known or imaginable, these appear to have especially high cultural fitness [we don’t change the names of colors].
-When new memes are added to the set, they enter into a specific and highly constrained fashion? system?

It is proposed then, that regularities in the linguistic decoding of color result from regularities in the neural coding of color in the brain, with the implication that this is a case of genetic mediation.

On the notion of inevitability and the sequence of cultural/technological evolution, Kevin Kelly states:
Each technological progression around the world follows a remarkably similar approximate order.
The direction of technological development is the same every time it happens.
Rock art always precedes sewing, and metalwork always follows claywork.

The Neural Coding of Color

The nervous system codes spectral radiation according to its wavelength in a way that creates a kind of biological categorization of the spectrum. (Durham, p218-219)

The absence of color-terms in any known culture for reddish-green or bluish yellow (as illustrated by Kay, 1978) is in parallel to the function of the lateral geniculate nucleus (LGN) of the brain, which uses a “spectrally opponent response process” via four nerve cells – two tuned to red/green, and 2 tuned to blue/yellow (DeValois and DeValois, 1966,1973).

The cross-cancelling of these cells leads to absence of fuzzy middle areas between the color pairs of red/green and blue/yellow. It also matches the sequence of the evolution of color terms (Berlin and Kay), which sees red-green-blue-yellow as primary colors from which others are differentiated.

(Note that although orange can be made of red-yellow, it is not present in the opposing sets of nerve cells; green is.

Regarding semantic correlation to neural coding, it appears that the favored variants which lead to the basic color terms of a culture (and thus have the most ‘fitness’) closely match the neural pattern. This is a case of Primary Value Selection, as defined by Durham as being opposite the Secondary Value Selection. Primary- is based on genetic programming, whereas Secondary- is built on top of the primary program, but differs in that it uses conscious decision-making.

William H. Durham, Coevolution: Genes, Culture and Human Diversity
Brent Berlin and Paul Kay, Basic Color Terms: Their Universality and Evolution. 1969, Berkeley
Paul Kay and Chad K. McDaniel, The Linguistic Significance and the Meanings of Basic Color Terms, Language 54, 1978
Kevin Kelly, What Technology Wants, 2010

Jan 2017, CBS News

In a study published in the academic journal eLife, researchers examined DNA methylation — fingerprints of DNA that can be inherited or altered by life experience and shape how our genes are expressed —among 573 Mexican and Puerto Rican children. DNA methylation reflects individual circumstances — for instance, PTSD stemming from traumatic experiences, air pollution from environmental conditions, after effects from maternal smoking, etc.

…a large fraction, one quarter, of the DNA fingerprints likely reflect biological signatures of environmental, social or cultural differences between the ethnic groups.

Different racial and ethnic groups tend to follow different diets, live in neighborhoods with varying levels of poverty and pollution, and are more or less likely to smoke. DNA methylation can reflect these subtle cultural and environmental differences.

Dr. Esteban Burchard, a physican-scientist and professor at UC San Francisco, supervised the study, which was 20 years in the making.

“It tells me there’s something biological to race. It tells me that we have a lot more work to do. Twenty-five percent of what we see is not due to biological differences, but things associated with the idea of race and ethnicity.”

As with the evolution of Color, notes in music began with a separation of octaves (perhaps male, female voices, etc.) and proceeded to divisions of 4ths and 5ths (etc.)
  -Curt Sachs, The Rise of Music in the Ancient World, East and West, 1943

The Lipps–Meyer Law predicts an 'effect of finality' for a melodic interval that ends on a tone which, in terms of an idealized frequency ratio, can be represented as a power of two.

The Lipps–Meyer law, named for Theodor Lipps (1851–1914) and Max F. Meyer (1873–1967), hypothesizes that the closure of melodic intervals is determined by "whether or not the end tone of the interval can be represented by the number two or a power of two", in the frequency ratio between notes.
  -Meyer, M.F. (1929). "The Musician's Arithmetic", The University of Missouri Studies, January.

RadioLab - Colors
Season 10 Episode 13
Listen to this podcast discussing how the Ancient Greeks, Homer included, were 'colorblind', and how the sky isn't really blue.


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