色の語彙が2個しかないと、世界はどう見える？#480
Do speakers of a language with only two color words actually fail to distinguish blue from red? Drawing on multiple psychological experiments with speakers of Dani, Tarahumara, and Berinmo, this episode tests the real-world effect size of the Sapir-Whorf hypothesis. The conclusion: the hypothesis holds, but the effect is far smaller than imagined—and is better understood as a story about the boundary between conscious and unconscious processing.
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What this episode answers
Can speakers of a language with no color vocabulary actually distinguish those colors?
Yes—speakers of languages lacking color vocabulary can still distinguish those colors. In a memory test where Dani speakers (whose basic color terms are only black and white) were shown color chips and asked to identify them later, their scores were no different from English speakers'.
What differences appeared between speakers with and without color vocabulary in experiments testing the Sapir-Whorf hypothesis?
The difference appeared in the form of the vocabulary-rich speakers being 'pulled' toward their categories. When shown three chips—green, blue, and an intermediate—and asked which the middle chip resembled more, English speakers (who distinguish green from blue) tended to call it 'green,' while Tarahumara speakers (who do not distinguish the two) answered nearly at random. The side without the vocabulary actually perceived the color more neutrally.
How can the perceptual distortion caused by language labels be made to disappear?
Two methods eliminated the bias experimentally: (1) showing only two adjacent chips at a time instead of all three simultaneously erased English speakers' skew; (2) assigning a concurrent verbal interference task—counting odd numbers aloud during the color judgment—eliminated the language-category effect entirely, bringing English speakers' scores in line with Tarahumara speakers.
How do Berinmo color categories differ from English ones, and what does that reveal?
Berinmo (spoken in New Guinea) uses a single word for both blue and green but has a separate word for bright green and yellow, whereas English distinguishes blue from green but not bright green from dark green. Correspondingly, English speakers tended to confuse dark green with bright green, while Berinmo speakers tended to confuse green with blue—a symmetrical result showing that language categories affect memory accuracy.
How do researchers position the 'true significance' of the Sapir-Whorf hypothesis?
Researchers see language as something that shifts the boundary between conscious and unconscious processing by a small but measurable amount. Perceiving a color is unconscious and works without vocabulary, but remembering, categorizing, and judging color is a conscious process that uses language labels—and that is where language intervenes. This boundary shift also provides a window for studying consciousness itself indirectly. Professor Iwamoto (言語心理学者), a language psychologist featured on the show, noted that the perceptual gap between pre- and post-language-acquisition (i.e., children versus adults) is far larger than any gap between speakers of different languages.
The Dani Experiment: Color Is Visible Even Without Words
In the 1990s, cognitive psychologist Rosch ran experiments with speakers of Dani, a language whose only basic color terms are black and white. Using the Munsell color system—a grid of color chips organized along three axes of hue, value, and chroma—she showed participants a chip, waited a short interval, then asked them to pick it out from the array.
Contrary to expectation, Dani speakers performed just as well as English speakers. They could tell blue apart from green despite having no word that distinguishes the two. A companion experiment had participants learn invented names for a prototypical red and an atypical red (roughly equivalent to vermilion). The typical color's name was easy to acquire; the atypical one was not. This mirrors the pattern in English-speaking children, who learn 'red' before 'vermilion,' suggesting that the human perceptual system contains universal 'focal colors' independent of language.
The Tarahumara Experiment: Vocabulary Pulls Perception
Tarahumara, spoken in northern Mexico, does not distinguish green from blue. Researchers showed Tarahumara and English speakers three color chips—green, blue, and an intermediate—and asked which of the outer two the middle chip most resembled.
English speakers tended to call the intermediate chip 'green,' because the intermediate range falls within the green category in English. Tarahumara speakers answered almost randomly—roughly 50/50—showing no pull toward either end. The side without the vocabulary was, paradoxically, perceiving the color more evenhandedly. This supports the Sapir-Whorf hypothesis, but in the opposite direction from intuition: it is the vocabulary-rich speakers who are distorted, not the vocabulary-poor ones.
A follow-up study modified the display so that only two adjacent chips were visible at a time rather than all three simultaneously. English speakers' bias disappeared entirely. When all three chips are visible together, there is enough time to attach a language label ('that's blue, that's green'); with only two chips at once, the task reduces to a simple color comparison, leaving no foothold for linguistic influence.
Verbal Interference: Strip Away the Label, Strip Away the Effect
Another striking experiment asked participants to count odd numbers aloud while performing a color discrimination task. The concurrent verbal task consumed language-processing resources, and the language-category effect vanished—English speakers matched Tarahumara speakers' scores. When the verbal channel is occupied with counting, there is nothing left to attach a color label.
The reverse was also demonstrated: hearing a relevant color name just one second before a discrimination trial began raised accuracy by roughly 10%. Pre-activating a color label gives the conscious labeling process a running start, boosting performance.
Berinmo, Traffic Lights, and Bananas: Where Language Moves the Line
A study of Berinmo, spoken in New Guinea, was published in *Nature* and drew wide attention. Berinmo has five basic color terms; one of them covers both blue and green (the so-called 'grue' category), while a separate term covers yellow and bright green. English, by contrast, distinguishes blue from green but not bright green from dark green. The two systems are mirror images of each other.
Memory tests confirmed the symmetry: English speakers confused dark and bright green; Berinmo speakers confused green and blue. Language categories measurably affected memory precision.
The same phenomenon appears with traffic-light yellow. German speakers, who call the color yellow (*gelb*), remember it as more yellow; Dutch speakers, who call it orange (*oranje*), remember it as more orange. In banana-color selection tasks, participants consistently chose a shade more intensely yellow than an actual banana's skin, suggesting that the language label 'banana = yellow' pulls memory away from reality.
The Real Significance of Sapir-Whorf: Consciousness Meets the Unconscious
Taken together, the current research consensus is that the Sapir-Whorf hypothesis is correct to a degree, but the effect is far smaller than popular imagination supposes. Language does not cause blue to look like green; it nudges category boundaries by a small margin—enough that more people classify an intermediate color as green, but no more than that.
Some researchers nonetheless find this small effect valuable as a window into consciousness research. Seeing a color is an unconscious process that works without vocabulary. Remembering, classifying, and judging a color is a conscious process that recruits language labels—and that is exactly where linguistic influence enters. When the verbal interference task forces a return to unconscious processing, the effect disappears; the very fact that this 'return' is observable in experiments means language is measurably shifting the boundary between conscious and unconscious processing. Researchers who study consciousness find this an unusually tractable indirect probe of a phenomenon that cannot be observed directly.
Professor Iwamoto (岩本先生), a language psychologist featured on the show, added a reframing: the perceptual gap between pre-language-acquisition children and language-competent adults is far larger than any gap between speakers of different languages. The Sapir-Whorf hypothesis, he suggested, is better read not as 'English speakers and Japanese speakers inhabit different worlds,' but as 'acquiring language profoundly changes how humans perceive the world at all.'
Takeaways
- Speakers of languages with no color vocabulary can still distinguish those colors—and in at least one experiment, the vocabulary-less side perceived an intermediate color more neutrally than speakers who had a word for it.
- The Sapir-Whorf effect is real but small: language shifts color-category boundaries only slightly, and simply counting odd numbers aloud while judging colors is enough to make the effect disappear.
- Language moves the boundary between conscious and unconscious processing by a measurable amount, and the perceptual change from acquiring language (child to adult) is far greater than any difference between speakers of different languages.
This article is edited from a machine transcript of the first 30 minutes of the episode. It is not an official summary — please listen to the episode itself.