Wednesday, October 11, 2006

Language and Cognition: a developmental framework revealed by color term analysis

There have been various claims about the ability of language to shape thought and perception, and one of the oft-cited phenomenon supporting this sapir-whorf hypothesis is the evolution of color terms in languages and how the lack of a color term in a language may influence the ability of that language user to make categorical distinctions between colors or to perceive the differing colors.

The basic color terms were originally proposed by Berlin and Kay (1969) in their seminal study 'Basic Color Terms, their Universality and Evolution' in which they proposed that different languages (written/ oral) have evolved to differing levels and that a culture would start with only two color terms, equivalent to black and white or dark and light, before adding subsequent colors closely in the order of red; green and yellow; blue; brown; and orange, pink, purple, and gray. Based on this they proposed a grouping of the ninety-eight languages studied into seven stages of an evolutionary sequence running from primitive languages with words only for WHITE and BLACK to more advanced languages with words for the whole range of colors.

  1. STAGE I : WHITE BLACK: Nine languages:7 New Guinea 1 Congo 1 South India
  2. STAGE II: WHITE BLACK RED: Twenty-one languages:2 Amerindian 16 African 1 Pacific 1 Australian Aboriginal 1 South India
  3. STAGE III
    1. STAGE IIIa: WHITE BLACK RED GREEN: Eight languages:6 African 1 Philippine 1 New Guinea
    1. STAGE IlIb: WHITE BLACK RED YELLOW:Nine languages:2 Australian Aboriginal 1 Philippine 3 Polynesian 1 Greek (Homeric) 2 African
  4. STAGE IV: WHITE BLACK RED GREEN YELLOW:Eighteen languages:12 Amerindian 1 Sumatra 4 African 1 Eskimo 380
  5. STAGE V: WHITE BLACK RED GREEN YELLOW BLUE:Eight languages:5 African 1 Chinese 1 Philippine 1 South India
  6. STAGE VI : WHITE BLACK RED GREEN YELLOW BLUE BROWN:Five languages:2 African 1 Sumatra 1 South India 1 Amerindian
  7. STAGE VII: COMPLETE ARRAY OF COLORS :Twenty languages: 1 Arabic 2 Malayan 6 European 1 Chinese 1 Indian 2 African 1 Hebrew 1 Japanese 1 Korean 2 South East Asian 1 Amerindian 1 Philippine
This schema of classification has been revisited in light of recent research, mostly the World Color Survey, and Kay and Maffi (1999), in Color Appearance and the Emergence and Evolution of Basic Color Lexicons, discuss the results to come up with a five stage developmental model of languages based on black, white, red, yellow, green, blue terms only and leave from the analysis other basic terms like brown, orange, purple and pink.

Their stages of languages are essentially the same as that of Berlin and Kay with stage IIIA (White, black, red, green) being more conman than stage IIIB (White, black, red, yellow) in the stage III languages.

Cognitive Daily ran a recent commentary on the World Color Survey , and as per the analysis presented there, it is apparent that the 41 languages covered there belonged to the stage V languages and the rest 69 languages belonged to stage IV languages (and in these languages as no separate word for Blue is present, hence the blue-green color is perceived as same and also labeled as Grue i.e. Blue and green are confused. The results that across cultures, people, if they have a term for a particular color in their language, then they do agree to the actual color hue that the color term corresponds to, across cultures, is a strong argument in favor of universality of color categories. thus, the blue of one language is the same as the blue of the other language and this is most probably due to the underlying physiology. See my blog posts related to color perception in humans in this regard.

Conversely, the fact that those languages that had no term for blue (but only had a common term Grue for blue and green), also found it difficult to distinguish between blue and green hues, suggests that having a term for a color does influence the way in which we categorize the colors and possibly also the way we perceive them. The latter (influence on perception) may be a more controversial claim, but the fact that color terms affect cognition (categorization) is relatively uncontroversial.

It is instructive to pause here, and note some facts from color vision physiology. The rods give us an ability to see even in dark and may have been the first to evolve, giving us the concepts of black and white. The cones may have evolved later to give a sense of colors. The opponent process utilizing Red cones and green cones gives rise to the perception of colors Red and Green. It is plausible that first the Red cones evolved (in evolutionary time-frame), giving a Red signal and thus a Red qualia/ Red color term. Later came the green cones to give a green signal and a green qualia/ green color term. The R+G opponent process was born later and refined the perception of Red and Green. It is also plausible that the brain started combining Red and Green signal (R+G) to perceive Yellow. Thus , a perception of Red, Green and Yellow would be generated by the brain, based on the two Red and Green cones only. The R+G =Y signal does exist in the brain and is one of the signals involved in the opponent processes of Blue-Yellow perception. The Blue cones apparently came the last and using the signal from blue cone and the Y=R+G signal, the opponent process of Blue-Yellow perception enabled, the perception of Blue qualia too and a corresponding color term for Blue too. Further, it is instructive to note that brown color (the stage V to stage VI transition of languages based on color terms) is perceived in the brain by a complex process involving signals from both R-G and B-Y opponent processes (specifically mixing of Red and Yellow at a point in space to give orange) and comparing and contrasting this information with the intensity (Black-white achromatic signal) of the surrounding region. This, leap from opponent-processes to a perception based on contrast with surrounding areas, marks a significant leap ( as is common in all developmental stage VI transformations) in perceptual mechanism employed and correspondingly the terms for Brown are more rare and difficult to be claimed as being universal in all languages and must have evolved later. The stage VII and VIII perceptual processes may determine how we perceive purple, pink, orange and gray but a more physiological analysis of perceptual mechanism involve would have to wait for another day, and by another more informed vision researcher. Here it would suffice to note that there are sound physiological reasons for why the color terms may have evolved in the way did over historical and evolutionary time scales and how some modern languages may still not be having terms for some colors the ability to distinguish which might have evolved recently and based on the different perceptual processes involved may not be the same in all cultures.

Before speculating further, it would serve us well to get acquainted with the latest consensus regarding the color terms and what they inform us regarding language and cognition. Kay and Regeir (2005) in their article Language, thought, and color: Recent developments, TICS , aptly summarize the state of the art view that involves an interactionist view where both Nature and Nurture, Universalism and Relativism have their place and are involved. As per them,

The language-and-thought debate in the color domain has been framed by two questions:
1. Is color naming across languages largely a matter of arbitrary linguistic convention?
2. Do cross-language differences in color naming cause corresponding differences in color cognition?

In the standard rhetoric of the debate, a ‘relativist’ argues that both answers are Yes, and a ‘universalist’ that both are No. However, a number of recent studies, when viewed in aggregate, undermine these traditional stances. These studies suggest instead that there are universal tendencies in color naming (i.e. No to question 1) but that naming differences across languages do cause differences in color cognition (i.e. Yes to question 2).



We have already seen how the concept of Focal colors (as outlined by Kay) is valid and seems to constitute a universal cognitive basis for both color language and color memory. Further, we have seen some neuro-physiological support for the emergence of focal colors red, yellow, green, blue and brown. Jameson and D’Andrade have argued that the universal focal colors are
salience maxima in color space and that universals of color naming flow from a process that partitions color space in a way that maximizes information. A recent study by Griffin LD (2006), The Basic Colour Categories are optimal for classification. J Roy Soc: Interface 3(6):71-85, seems to support this hypothesis and posits that the eleven basic color categories identified by Kay are optimal and useful in computer machine vision too. All these evidences are compatible with each other and suggest that the basic properties and number of color categories, compatible with optimal color space partitioning, have led to the emergence of corresponding neuro-physiological/ perceptual apparatus in humans to detect these categories, and has thus led to that many number of color terms to evolve in the degree of complexity of these mechanisms/ incremental advantage they provide in categorization.

On the relativistic side it is claimed, that the cognitive variables like privileged memory, similarity judgments, or paired associates learning for focal colors are well predicted by the boundaries of each language’s color categories: a form of categorical perception of color. Since these boundaries vary across languages, speakers of different languages apprehend color differently. Moreover, these linguistic differences seem to actually cause, rather than merely correlate with, cognitive differences.The argument is further that color terms are arbitrary and the color terms determine the perception of colors absolutely. Roberson, Davidoff et al, in Color Categories are not universal: New evidence from Traditional and Western cultures , argue that the evidence supporting focal colors and the concept of universal categorical perception arising from them, . viz privileged memory for them or paired associate learning for the proposed universal colors, is rendered incorrect, when the effect of verbalization (or use of linguistic tokens) is taken into account. As per them (emphasis mine) :

In native English speakers a series of experiments found that verbal interference selectively removed the defining features of Categorical Perception. Under verbal interference, there was no longer the greater accuracy normally observed for cross-category judgments compared to within-category judgments. It thus appears that while both visual and verbal codes may be employed in the recognition memory of colors, subjects only make use of verbal coding when demonstrating Categorical Perception (Roberson & Davidoff, 2000). In a brain-damaged patient suffering from a naming disorder, the loss of labels radically impaired his ability to categorize colors

Participants from a traditional hunter-gatherer culture, whose language contains five basic color terms (under the definition of Kay Berlin & Merrifield, 1991), showed no tendency towards a cognitive organization of color resembling that of English speakers. They did not find best examples of English color categories easier to learn or remember than poor examples and, in a further set of experiments, evidence of Categorical Perception was found in both languages, but only at their own linguistic category boundaries.

Although the authors draw extreme conclusions from their findings, but Kay moderates the viewpoint and concludes: (emphasis mine)

It has been widely assumed that language is the cause of color categorical perception. This is suggested since – as we have seen – named category boundaries vary across languages, and categorical perception varies with them. However, Franklin and Davies have found startling evidence of categorical perception at some of these same boundaries in pre-linguistic infants and toddlers of several languages. Thus, some categorical color distinctions apparently exist prior to language, and may then be reinforced, modulated, or eliminated by learning a particular language.


This finally brings us to the post by Developing Intelligence regarding labels as an accelerator of ontological development. In this, though in the beginning itself, Chris dismisses the strong form of Sapir-Whorf hypothesis (esp. in relation to colors) , he presnts a study that leads to a reasonable conclusion that language can accelerate the process of sortal/kind discrimination, such that a skill normally only demonstrated by 12-month-olds was in this case demonstrated by 9-month-olds with the proper linguistic input. Here, one is not arguing that the sortal/kind discrimination would not have been possible in the absence of linguistic inputs- one is merely claiming that the sortal/kind discrimination is facilitated by language and happens early in the developmental cycle based on linguistic labels. And definitely not having labels leads to a different cognitive/ perceptual experience in the infants as compared to those infants who use labels and can make the sortal/kind discrimination.

Form the above, it may be inferred, that though universal focal colors and color categories do exist (based on underlying neurophysiology or spectral properties of the visible-to-humans world), they may be available to consciousness at different stages of an infant's (or a culture or a language's ) development, and having labels or color terms for the categories may facilitate an early maturation of the color categorizations faculty. Depending on where a culture, or language is on its developmental path, lack of proper color terms may limit their ability to perceive colors as belonging to different categories for which they don't have a label.

Interestingly, in the Davidoff study, a brain damaged patient suffering from an inability to label things, was impaired in categorizing colors.

Though the exact mechanism by which labels or color terms may work is still elusive with multiple competing hypothesis (viz., labels facilitate sortal/kind distinctions by aiding a domain-general, non-linguistic process, such as memory; or that labels increase the salience of perceptual feature differences between object) , yet it is clear that labels are instrumental and play a definitive role in the ontological development of the child.

One may take a strong line and argue, that in the absence of color terms or labels, one would not be able to have a full cognitive color categorization or sortal/kind discrimination experience, but even if one does not subscribe to the extreme view, it seems plausible that different developmental levels of languages identified by the linguistic color terms in the languages correspond to different levels of cognitive experiences that are more readily available in the corresponding culture.

Thus, while language does affect thought and vice versa, both may be constrained by the developmental stage at which a culture is. The cognitive experience and the cognitive developmental stage from which that experience results would correspond to the stage of development of that language and vice versa. Thus, some cultures, by not using a language that is fully evolved/ developed, may not be experiencing the full range of cognition and emotion that is humanly possible. Conversely, based on the linguistic devices utilized by a culture, their cognitive experiences may differ from another culture that utilizes another incompatible set of linguistic devices.

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4 comments:

Archana Bahuguna said...

Sorry my comment has nothing to do with your blog, but do u have a profile in Orkut? I met Shailesh Vyas and its been nice getting back in touch with him. Why dont u also make one profile there?

And I commented on ur tag. Pls read.

Sandy G said...

Well someone has to invite me to Orkut, before I can create a profile there and it seems all my dear friends (like you) have forgotten to send me invitations. Of course you can be excused because of your absent-mindedness, but not Shailesh. His punishment is that he would have to read all the posts on this blog to atone.

Just kidding! Will create a profile and send you a link.

I had read your comments on my tag earlier,and have now commented on them too, so now its your time to read and re-comment!

andreas said...

hi,

sorry to nitpick - this does not go againt the gist of your entry, it's only about one specific paragraph:

do you have some references for the evolutionary history of our color vision system?

what you write seems somewhat strange to me - be careful with the "it is plausible that" in evolutionary considerations - it's pretty much a hard science these days.

anyhow, while the jury may still be out on some of the details - the big picture is rather different, I think:

all mammals are pretty color deficient, e.g. compared to birds, as we're the descendants of nocturnal critters (the first mammals) with a reduced system...

these critters changed their original cone dominated system into a rod dominated system (which is pretty much useless under conditions of daylight) and drastically reduced their cones (so no matter which evolved first (much earlier...), our rods piggyback on the originally cone-dominated design)

while most mammals still have only two (at most) cone channels, we primates (aren't we lucky) got a third channel back - by duplication of the middle-to-long wave channel into a new long wave channel (your "red cones") - which i am pretty sure were the last to come (as most mammals are not able to differentiate red from grey of similar intensity)

see e.g.
Ahnelt PK, Kolb H (2000). The mammalian photo-receptor mosaic-adaptive design. Prog Retin Eye Res 19: 711-77

regards
andreas



It is instructive to pause here, and note some facts from color vision physiology. The rods give us an ability to see even in dark and may have been the first to evolve, giving us the concepts of black and white. The cones may have evolved later to give a sense of colors. The opponent process utilizing Red cones and green cones gives rise to the perception of colors Red and Green. It is plausible that first the Red cones evolved (in evolutionary time-frame), giving a Red signal and thus a Red qualia/ Red color term. Later came the green cones to give a green signal and a green qualia/ green color term. The R+G opponent process was born later and refined the perception of Red and Green. It is also plausible that the brain started combining Red and Green signal (R+G) to perceive Yellow. Thus , a perception of Red, Green and Yellow would be generated by the brain, based on the two Red and Green cones only. The R+G =Y signal does exist in the brain and is one of the signals involved in the opponent processes of Blue-Yellow perception. The Blue cones apparently came the last and using the signal from blue cone and the Y=R+G signal, the opponent process of Blue-Yellow perception enabled, the perception of Blue qualia too and a corresponding color term for Blue too. Further, it is instructive to note that brown color (the stage V to stage VI transition of languages based on color terms) is perceived in the brain by a complex process involving signals from both R-G and B-Y opponent processes (specifically mixing of Red and Yellow at a point in space to give orange) and comparing and contrasting this information with the intensity (Black-white achromatic signal) of the surrounding region. This, leap from opponent-processes to a perception based on contrast with surrounding areas, marks a significant leap ( as is common in all developmental stage VI transformations) in perceptual mechanism employed and correspondingly the terms for Brown are more rare and difficult to be claimed as being universal in all languages and must have evolved later. The stage VII and VIII perceptual processes may determine how we perceive purple, pink, orange and gray but a more physiological analysis of perceptual mechanism involve would have to wait for another day, and by another more informed vision researcher. Here it would suffice to note that there are sound physiological reasons for why the color terms may have evolved in the way did over historical and evolutionary time scales and how some modern languages may still not be having terms for some colors the ability to distinguish which might have evolved recently and based on the different perceptual processes involved may not be the same in all cultures.

Sandy G said...

Hi Andreas,

Thanks for dropping by and commenting. constructive criticisms are always helpful and spur you onwards. The paragraph that you quote was in a conjectural spirit, proposing a possible evolutionary trajectory- the contention was never that this was the actual scenario.

Since then, I have reviewed some recent literature and have written a detailed post regarding the evolution of color vision . Maybe we can continue the discussion in that posts context.

I still maintain, that in primates the red color detection precede Blue/Yellow.