Wednesday, February 06, 2008

Russsinas have a richer discriminative experience of light and dark blue qualia

I have blogged extensively earlier regarding language, color and the sapir -whorf hypothesis. My position in the above is clear, I lean towards the sapir-whorf hypothesis and a mild form of linguistic determinism. Now a new study (which I had missed earlier) by Lera Boroditsky presents further corroborating evidence that language influences even such basic functions as color perception. As per their 2007 PNAS paper, Russians are better (more speedily) able to distinguish between the light blue and dark blue color in an objective color perception task, thanks to the fact that Russian has a different color term for dark blue and a different one for the light blue. It is an excellent paper and I present some excerpts from the introduction:


Different languages divide color space differently. For example,the English term ‘‘blue’’ can be used to describe all of the colors in Fig. 1. Unlike English, Russian makes an obligatory distinction between lighter blues (‘‘goluboy’’) and darker blues (‘‘siniy’’). Like other basic color words, ‘‘siniy’’ and ‘‘goluboy’’ tend to be learned early by Russian children (1) and share many of the usage and behavioral properties of other basic color words (2). There is no single generic word for ‘‘blue’’ in Russian that can be used to describe all of the colors in Fig. 1 (nor to adequately translate the title of this work from English to Russian). Does this difference between languages lead to differences in how people discriminate colors?

The question of cross-linguistic differences in color perception has a long and venerable history (e.g., refs. 3–14) and has been a cornerstone issue in the debate on whether and how much language shapes thinking (15). Previous studies have found cross-linguistic differences in subjective color similarity judgments and color confusability in memory (4, 5, 10, 12, 16). For example, if two colors are called by the same name in a language, speakers of that language will judge the two colors to be more similar and will be more likely to confuse them in memory compared with people whose language assigns different names to the two colors. These cross-linguistic differences develop early in children, and their emergence has been shown to coincide with the acquisition of color terms (17). Further, cross-linguistic differences in similarity judgments and recognition memory can be disrupted by direct verbal interference (13, 18) or by indirectly preventing subjects from using their normal naming strategies (10), suggesting that linguistic representations are involved online in these kinds of color judgments.

Because previous cross-linguistic comparisons have relied on memory procedures or subjective judgments, the question of whether language affects objective color discrimination performance has remained. Studies testing only color memory leave open the possibility that, when subjects make perceptual discriminations among stimuli that can all be viewed at the same time, language may have no influence. In studies measuring subjective similarity, it is possible that any language-congruent bias results from a conscious, strategic decision on the part of the subject (19). Thus, such methods leave open the question of whether subjects’ normal ability to discriminate colors in an objective procedure is altered by language.

Here we measure color discrimination performance in two language groups in a simple, objective, perceptual task. Subjects were simultaneously shown three color squares arranged in a triad (see Fig. 1) and were asked to say which of the bottom two color squares was perceptually identical to the square on top.

This design combined the advantages of previous tasks in a way that allowed us to test for the effects of language on color perception in an objective task, with an implicit measure and minimal memory demands.

First, the task was objective in that subjects were asked to provide the correct answer to an unambiguous question, which they did with high accuracy. This feature of the design addressed the possibility that subjects rely only on linguistic representations when faced with an ambiguous task that requires a subjective judgment. If linguistic representations are only used to make subjective judgments in ambiguous tasks, then effects of language should not show up in an objective unambiguous task with a clear correct answer.

Second, all stimuli involved in a perceptual decision (in this case, the three color squares) were present on the screen simultaneously and remained in full view until the subjects responded. This allowed subjects to make their decisions in the presence of the perceptual stimulus and with minimal memory demands.

Finally, we used the implicit measure of reaction time, a subtle aspect of behavior that subjects do not generally modulate explicitly. Although subjects may decide to bias their decisions in choosing between two options in an ambiguous task, it is unlikely that they explicitly decide to take a little longer in responding in some trials than in others.

In summary, this design allowed us to test subjects’ discrimination performance of a simple, objective perceptual task. Further, by asking subjects to perform these perceptual discriminations with and without verbal interference, we are able to ask whether any cross-linguistic differences in color discrimination depend on the online involvement of language in the course of the task.

The questions asked here are as follows. Are there crosslinguistic differences in color discrimination even for simple, objective, perceptual discrimination tasks? If so, do these differences depend on the online involvement of language? Previous studies with English speakers have demonstrated that verbal interference changes English speakers’ performance in speeded color discrimination (21) and in visual searching (22, 23) across the English blue/green boundary. If a color boundary is present in one language but not another, will the two language groups differ in their perceptual discrimination performance across that boundary? Further, will verbal interference affect only the performance of the language group that makes this linguistic distinction?


They then go on to discuss their experimental setup (which I recommend you go and read). Finally they present their findings:

We found that Russian speakers were faster to discriminate two colors if they fell into different linguistic categories in Russian (one siniy and the other goluboy) than if the two colors were from the same category (both siniy or both goluboy). This category advantage was eliminated by a verbal, but not a spatial, dual task. Further, effects of language were most pronounced on more difficult, finer discriminations. English speakers tested on the identical stimuli did not show a category advantage under any condition. These results demonstrate that categories in language can affect performance of basic perceptual color discrimination tasks. Further, they show that the effect of language is online, because it is disrupted by verbal interference. Finally, they show that color discrimination performance differs across language groups as a function of what perceptual distinctions are habitually made in a particular language.


They end on a philosophical note:

The Whorfian question is often interpreted as a question of whether language affects nonlinguistic processes. Putting the question in this way presupposes that linguistic and nonlinguistic processes are highly dissociated in normal human cognition, such that many tasks are accomplished without the involvement of language. A different approach to the Whorfian question would be to ask the extent to which linguistic processes are normally involved when people engage in all kinds of seemingly nonlinguistic tasks (e.g., simple perceptual discriminations that can be accomplished in the absence of language). Our results suggest that linguistic representations normally meddle in even surprisingly simple objective perceptual decisions.


To me this is another important paper that puts sapir-whorf hypothesis on the forefront. I would love to hear from those who do not endorse the spair-whorf hypothesis as to what they make of these results?

hat tip: Neuroanthropology blog.

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6 comments:

Gilbert Wesley Purdy said...

Let's consider a simple functional model. T=1) Ancient Russians, it turns out, needed to distinguish between "goluboy" and "siniy" in order to achieve some function. Those who could do so were culturally selected for. The word entered the language representing and perpetuating the capability to distinguish between the two blues. T=2) The need to distinguish becomes outmoded. The word, however, lives on slowly becoming archaic. T=3) The general population loses familiarity with the one of the words that is no longer functional but it lives on in dictionaries.

Now let's question the model:

Can words come into a language by any other means than T=1? If discrimination between "goluboy" and "siniy" were selected for throughout the population by genetic rather than cultural evolution would there be any need for language to provide the capability?

Once T=2 had been reached, how would it affect the results of Boroditsky's experiment? Once T=3 had been reached?

Boroditsky surmises that:

"Further, cross-linguistic differences in similarity judgments and recognition memory can be disrupted by direct verbal interference (13, 18) or by indirectly preventing subjects from using their normal naming strategies (10), suggesting that linguistic representations are involved online in these kinds of color judgments."

But might this effect only apply to T=2? At T=1 the color is "informing" the language to the point where naming strategies might not be necessary. At T=3 the word exists only in dictionaries. The "goluboy" and "siniy" distinction no longer exists in the active language, presumably removing the ability of Russians to discriminate between them as effectively.

One final question. Does a non-native speaker who has become fluent in Russian at T=1 gain the ability to discriminate between the colors as effectively as native speakers? T=2? T=3? More effectively than those who don't speak Russian?

What about a non-native speaker who has become fluent but has never seen examples of the colors? Only has been taught that one is a lighter blue than the other? Does he or she gain the ability to discriminate more effectively between the two colors? If not, why not?

To my (pro Sapir-Whorf) mind, the effect of verbal interference could be the affect of testing those who are somewhere along the time-line of T=2. It could be representative of the fact that the one of the colors is in the process of being abstracted into a mere word. If both terms described an immediate functional need, the mediacy of language might not be present.

Sandy G said...

Gilbert,
you raise some interesting points here. Let me try to address some of them.

1. "Can words come into a language by any other means than T=1? If discrimination between "goluboy" and "siniy" were selected for throughout the population by genetic rather than cultural evolution would there be any need for language to provide the capability?"
Here, I beg to differ. It may be possible that color discrimination between goluboy and siniy had selection advantages and was genetically selected for; and in this case as the population (over selection period) becomes more and more able to distinguish between goluboy and siniy, the corresponding language terms for dark blue and light blue would also evolve. Genetic selection might have been possible; but I doubt that that is the case. If their were stable genetic differences in Russsians vis-a-vis others ability to discriminate between dark blue and light blue, then the capability to do so should not have disappeared in the Russian data set when they were subjected to verbal interference. The fact that Russians too lost the ability to distinguish between dark blue and light blue when subjected to verbal interference strongly suggests that this discriminative superiority is solely due to linguistic factor sand not due to genetics.

2. As for whether Brodotisky's experiments would differ based on T=2 or T=3, yes at T=3 one should not see the Russian discriminative advantage.

3. I agree that at T= 1 and T=3, the naming strategies may not be effective and provide no Russian advantage.

4. About the non-native speakers, I believe they might show the Russian advantage only at T=2. They might not show any advantage at all as the underlying circuitry (the verbal circuitry feeding back to perceptual circuitry) might be formed during a critical developmental window.

5. Lastly, I do not agree, that if both terms described an immediate function need, then mediacy of language might not be required. Red and green both serve immediate functional needs in English and yet we have different language terms for it. the mediacy of language is present.

Overall though I found your comment very thought provoking.

Gilbert Wesley Purdy said...

Thank you for the extended reply. I assume that it was you who visited my humble little Online Bibliography earlier. Perhaps you noticed that The Mouse Trap appears among its side-links as one of the better science blogs that I am aware of.

I am curious about one thing relating to your visit. Does Maharashtra mean "Great nose (or face)" in sanskrit?

That out of the way, I would like to reply in particular with your #5. I think that you may well be making my point.

First, are you aware of any experiment similar to Brodotisky's to determine if Americans living in the U.S. discriminate between red and green better than those living in other countries? Based upon an insufficiently controlled, but widely known, experiment, in which the subjects have a demonstrable immediate need to discriminate red from green, verbal interference would seem clearly not to affect the results appreciably. Of course, the experiment is called driving and American drivers fit either one of two categories as it relates to this question: either 1) deficient or dangerous drivers (who are culturally selected against by various means) or 2) drivers who discriminate between red and green, in a fraction of a second, regardless of even the most obtrusive verbal disruptions and always manage to stop for a red light.

I think that experience suggests that persons from cultures that do not employ red and green for their traffic lights (or to supply some other immediate need) will discriminate less effectively and will probably be more prone to verbal interference. This also suggests, by the way, that if traffic lights in the U.S. employed the colors of dark and light blue: 1) Americans would invent separate names for the two shades (or give different mental values to the tonal descriptions effectively making them designate a difference of type); 2) They would be more effective in discriminating than T=2 Russians; and 3) verbal interference would have little or no effect on the supperior ability to discriminate between the colors.

Sandy G said...

Gilbert,
I have visited your online bibliography earlier too and many thanks for featuring the mouse trap there. Maharasthra means 'great nation'.

As for #5 , I find the example of people in US using dark an dlight blue as traffic lights very informative. I still disagree with the 3) that verbal interference would not have any effect. I believe that if such traffic light usage was there and English had also invented new words to discriminate between dark and light blue, we would definitely see that verbal interference affects discriminative performance. Alas this cannot be settled by experimental investigation.

Wesley said...

It seems to me that the best interpretation of this study is that the categories used in language can be found elsewhere in the brain as well.

If you have a linguistic category that separates Red1 from Red2, this will lead to a lot of training for the discrimination of these two colors. And, in my opinion, the fact that training can lead to new divisions in perceptual categories is not very surprising, nor novel.

So, it is simply a result of lots of practice at discrimination that causes the noted effect of faster discrimination times (a result seen elsewhere in psychological research). That this practice happens to be the result of a linguistic category is moderately interesting, but I dont think it supports anything like the sapir-whorf hypothesis. In other words, it is training that drives the result, and what drives the training may be interesting, but I can't see why it is terribly exciting.

Sandy G said...

Wesley ,

The fact that verbal interference was abkle to disrupt the advantage enjioyed by russians is a strong prdictor that the effect is due to verbal labels and not due to perceptual training. If the effect was due to perceptual training, it should not have been effecetd by Verbal interference.

Also , I suggets this advantage would be more prominent in RVF, which is processed by left hemsiphere and would again show a linguistic involvement.