I am looking out my hotel room window in Hiroshima in this very instant, and I even got my wife to confirm it: The traffic lights definitely are GREEN.

I'm glad you mentioned that you had your wife confirm, because I'm convinced my wife sees more colours than I do, and I can't be the only one. I've had this exact discussion.

    What colour is this?  Blue.
    No,  can't you see it's green?  Maybe it has some green in it
    Okay, so is it blue or green?  Yes!

Why did you ask me then?

Yes, on average women can perceive more colors than men [1]

Anecdotally, in high school we all took this test for a class [2] and the girls did a lot better than us. Although some guys were able to score pretty well on it. I don’t remember if this was the exact test but it’s very similar.

[1] https://pubmed.ncbi.nlm.nih.gov/21675035/

[2] https://www.xrite.com/hue-test

As a dude who scores perfect on these color tests (this is my superpower), it’s funny on male-dominated places like here and reddit when people discuss logo color changes.

They’re always long threads of of very confident people saying how there isn’t even a difference and I’m like lol

Apparently my color perception is as good as I've always thought it was. I scored a 0 on that.

Oh, I’ve taken that test before. I’m a man, but I got a perfect score. I’ve always had a very easy time distinguishing shades and hues of color.

>[2] https://www.xrite.com/hue-test

" Best Score for your Gender -1000000 Worst Score for your Gender 1700045439

About your score: A lower score is better, with ZERO being a perfect score. The circle graph displays the regions of the color spectrum where your hue discrimination is low."

I hate this kind of stuff. WTF is that Best Score?

Hahaha:

> Best Score for your Gender -2147483648

> Worst Score for your Gender 2147483647

It goes from -2147483648 to 2147483647 for me, which I'm interpreting as "our langauge doesn't distinguish signed from unsigned integers, and nor do our developers". Possibly there's also some lack of validation of client-side data involved.

I wonder if there might be a language aspect to this, with males in the US generally having less familiarity with words for the in between colors leading to more difficulty distinguishing between them, with people with more words for greenish shades for example having an easier time seeing different shades of green.

https://boingboing.net/2011/08/12/how-language-affects-color...

I'd have to dig up references, but I understand it's a pretty well documented effect that having words for colors is directly related to a population seeing more distinction for those colors.

If I recall, some early societies didn't have a distinction between green and blue. Given that blue often doesnt show up naturally outside of the sky and it's reflections. And in those populations they would be much less sensitive to distinctions in blue-green.

Which is exactly what the article is about ;) (Well, one example of an early society that didn't distinguish between green a blue.)

For early societies, you might be thinking of the Greeks, though apparently it's somewhat common between languages?[1] For Greek the idea to originate from Homer's writings, with colors being more described in terms of how light or dark they are versus specific hues.[2]

[1]https://en.wikipedia.org/wiki/Basic_Color_Terms

[2]https://en.wikipedia.org/wiki/Wine-dark_sea_(Homer)

Like many siblings, I'm male and got a perfect score as well. I don't think that I have perfect vision, but I'd rather assume the test is flawed.

It's pretty clear that it's "Based on the Farnsworth Munsell 100 Hue Test," and "this is not a replacement for the full test!" I think if you did particularly poorly on the online test then it's worth looking at whether you need to do the full test, as you might have colour blindness (or a terrible monitor). But a perfect score isn't super-meaningful.

Looking at this test on my monitors I would bet it's the 'terrible monitor' before color blindness by a longshot, one shows pretty good color the other is entirely washed out.

What's the scale is not clear. It says 0 is perfect but what about 5?

While comparing it shows typical scores as -(large number) to +(large number).

A lot of that is learned..

However, there are people who are tetrachromats, have cones most sensitive to a fourth frequency of light in their eyes, and those people are also overwhelmingly women.

If I recall correctly there has only been one human actually shown to have tetrachomacy, and the supposition that there are a exceedingly small number of additional ones. I think there was a mechanism proposed that would mean they were all biologically female, but can't remember details.

It certainly seems to be rare enough to have no practical impact (except to perhaps the tetrachromat, who presumably has different metatmers perception etc.)

> those people are also overwhelmingly women.

As far as I understand it takes having two X chromosomes with different versions of the gene that encodes the receptors for green, so only women can be tetrachromats.

I scored a 6, but their lack of data on the distribution of scores makes that pretty hard to interpret.

Does anybody know how to read that?

> https://www.xrite.com/hue-test

Fun test! I'd note for others, the quality of your screen can make a difference - I found one of the lines a lot easier on my phone (first try) than on my computer (second try) - though I got perfect both times.

Your score: 2

Best: segmentation fault (core dumped)

Maybe not more colors, but more easily distinguishes them: https://www.psychologytoday.com/intl/blog/brain-babble/20150...

This is different from tetrachromacy, where some women really do see more colors: https://www.optimax.co.uk/blog/tetrachromacy-superhuman-visi...

The mothers of some red-green colorblind children are tetra chromatic, so they actually see more. I think hexa chromatic also exists.

Edit: somehow didn't notice you'd linked this.

I edited it in like under a minute afterwards, you may have opened the page right in the middle. I don't usually bother with an "Edit:" note if it's that fast.

> because I'm convinced my wife sees more colours than I do

A sizeable percentage of women have tetrachromy (5% ? I forgot the exact number but it's not nothing). AFAIR men do not have tetrachromy.

So, basically, some women do actually see more colours than all the men and than most other women.

Maybe your wife has tetrachromic vision? (not sure how it's called)

Please report the exact wavelength for verification.

There's an app for that

… in electron-volts to the precision of 10 decimal places.

Colors are not necessarily a single wavelength, and the human visual system can't distinguish between identical "tristimulus" caused by a single wavelength or a mixture of wavelengths. This is why color monitors with red, green, and blue pixels work. The red, green, and blue are designed to stimulate your long, medium, and short wavelength receptors. Models like CIE1931 map wavelengths to tristimulus values, which your monitor then maps to the right intensity of its red, green, and blue. (Display technology is, of course, imperfect. You can see redder reds, greener greens, and bluer blues than your monitor can emit, though newer monitors with Adobe RGB or DCI-P3 have redder reds. It's also possible that the green light from your monitor is not perfectly stimulating only your medium wavelength receptors.)

Some colors that look very real cannot be a single wavelength of light, like magenta. That color is a figment of our imaginations. (Rather, there is no wavelength of light that stimulates your long wave receptors and short wave receptors without stimulating the medium wave receptors. But, magenta does, because it's actually a blue wavelength and a red wavelength.)

Stop ruining my jokes with facts!

My memory form my time living in Japan is that they do not have a consistent shade of blue/green that their traffic lights conform to. You will see completely different colors depending on the location, and even see different colors within the same location. Some areas are more blue and some areas are more green.

I have never seen the big main lights using blue instead of green anywhere in Japan; the traffic lights for pedestrians however were blue in some places.

you would know if you read the article :)

Are you sure? This seems to be the full article:

> www.rd.com

> Checking if the site connection is secure

> www.rd.com needs to review the security of your connection before proceeding.

weird, maybe you have to send them your blood, fingerprints, and a list of your favorite laundry detergents in order to get through?

From the Guidelines:

>Please don't comment on whether someone read an article.

Which you'd know if you read the guidelines (:

https://news.ycombinator.com/newsguidelines.html

I have been to Japan a couple of times. The first time I was there in 2016 many of the lights were very blue with hint of green. I noticed when I was there over the summer that the lights were getting greener, many of them pretty much just green. I think they have been transitioning, perhaps as they have updated to LED lights or something they have been making them more green?

I wouldn’t be surprised if it had something to do with the Tokyo olympics. Are other cities also green now?

Yes, I was in several other cities and noticed it throughout. Spent half of the summer in Sapporo (my favorite Japanese city so far!) and it was definitely noticeable there.

It depends on where you are in Japan, it's mostly Green but there are some Blue ones occasionally.

And yet another data point: there are places in France with blue lights, instead of green.

How old are you roughly? The reason I ask is that the eye lens yellows with age and transmits less blue and violet through. So colors that would look blue-green to a younger eye would look more green to an older one.

The "go" signal in traffic lights in Japan is 蒼い (あおい) "aoi".

That adjective in Japanese means both blue and green. The Japanese language didn't have a widely-adopted word for just "green" - 緑 (みどり) "midori" - until after WWII.

Green apples or vegetables are still "aoi", for example. I lived in Japan for four years and never saw a blue traffic light.

Do you know more about the history of this color use? It’s surprising to me that midori uses the kanji for green in Chinese if it’s such a recent idea in Japan.

What I was told, when I asked about this, was that "midori" existed as a Japanese word but was not in common usage. That is what Mizutani-san from JAL Academy told me back in 2009 anyway.

EDIT: I apologize for the vague sourcing!

Green (綠) in Chinese also came later. In Old Chinese, 青 was generally used to represent both blue and green colors.

While the word 綠 to mean green has been attested as far back as 1000 BC, the idea that it was a separate color rather than describing a shade of 青 is relatively more recent. Wikipedia[0] indicates that it was adopted in the early 20th century in Chinese (as part of vernacular language reforms) and after WWII in Japanese, though these claims are currently marked with [citation needed]. While both are relatively recent, the usage in Chinese did have a longer period of time to take hold.

[0] https://en.wikipedia.org/wiki/Blue%E2%80%93green_distinction...

I don’t know about the green kanji, but the traditional “Jueju” Poem by Chinese poet Du Fu has the line “山青花欲然”, and “青” the Kanji for Blue in Japan means green in this context, as it describes “山” which means mountain.

By the way there’s a variety of kanji that reads “aoi” in modern Japanese. 青い, 蒼い, 碧い are all “aoi”, but we use 青い mainly as blue today.

Oh that’s interesting. Yeah 青 is used in Chinese as another word for green. I don’t know that it has any connotations of blue, but I did grow up in the US, so perhaps there’s nuance to that character I’m unaware of, or the character slightly changed meaning when made a kanji.

This is pretty far off base - for a start, the first JP law on traffic lights in the 1930s used midori, not ao. Per jp references, ao/midori split into distinct meanings around the Heian~Kamakura periods (so 800-1000 years ago).

> for a start, the first JP law on traffic lights in the 1930s used midori, not ao.

Have a source for that? This section[1] of the ja.wikipedia article could apparently use your revisions - both kanji are acceptable.

[1] https://ja.wikipedia.org/wiki/%E4%BA%A4%E9%80%9A%E4%BF%A1%E5...

That link doesn't mention the law I referenced, so I don't know what you're asking for.

If you want a source that the 1930 law used midori, see here, under「発祥期」:

https://ja.m.wikipedia.org/wiki/%E6%97%A5%E6%9C%AC%E3%81%AE%...

Are you referring to reference number 184? I'm looking for a primary source for your statement that midori was the colour standardized in law since the 1930s, because the section I linked about colours explicitly calls out ao and notes the difference in different jurisdictions.

> your statement that midori was the colour standardized in law since the 1930s

In 1930, not since the 1930s. The 1930 law used midori, but it was changed to ao in 1947 after that became the more popular usage. The page you linked was about the current law.

A lot of traffic lights in the US are actually "not just green".

The traffic lights have an abnormally high amount of blue light for being an overall green light, to help people with red-green colorblindness to tell the difference between the red and "green" light.

If you take a look at the green light on a dash cam, you might see that the color is abnormally bluer than what you might see in real life.

Japan has green traffic lights, there are no two ways around it. I’ve lived in Japan for 3 years in all the major cities. They are green, just like everywhere else. They just call them blue.

Why they do that is something you can argue about and I’ve heard Japanese try and come up with all sorts of explanations:

“The character for blue is easier to learn than the one for green, so it’s better to say blue with children.”

“They used to be blue, so we still just call it that”

“Green isn’t an original Japanese color. Before foreigners arrived we didn’t call anything green”

“They are blue!” - usually these are people who will call traffic lights in Europe and smarties blue even when speaking English.

It’s just a quirk. I think Japan places the border between blue and green different from most western cultures and that gives.