Lest you think this is merely an academic problem, I ran into a catastrophic, real-world case where it mattered.
I lost a notebook at a big box store. It had major sentimental value to me[1]. I called their Lost & Found and asked if someone had returned a green notebook. They insisted they didn't have one.
When I went to the store in person, they had it. Because they felt that it wasn't green, but blue. And (presumably) that no one would describe it as green, so they should return False for "matches what a green-notebook-seeking human wants?"
Here's the notebook: http://i.imgur.com/AlQAZBJ.jpg
So, for the linked question: whenever answering a question, you need to know why you're answering it. It affects the answer! Consider these purposes:
1) "I want to know if other people will agree that this is a green notebook."
2) "I want to know if I should say this definitely-doesn't-match when someone comes looking for a green notebook."
3) "I want to know if this notebook reflects almost entirely green light."
Case 2 is the one I was interested in. In that case, 10% respondents are enough to say "hey, that might be a match".
[1] I know, "you shouldn't have brought it out with you".
> Because they felt that it wasn't green, but blue.
This is just bizarre on their part. "Guys calling in about a green notebook, one of the three items in our lost and found is a notebook, but... oh it's a blue one. Just tell him we don't have it."
Yeah, this points to "employee is a jerk".
Normal employee: "We have a notebook here. Can you describe it more? Something written on the inside, maybe?"
Maybe the employee wanted a new notebook and was hoping to wait out the lost and found window.
Yes! Fortunately, I did have my name in the back. But I never anticipated that someone would so adamantly think it was some other color. I could understand someone calling it blue, but not "definitely not green".
There's a wall at my parents house which to me always looked green. I referred to it as green and my sister and mother seemed to get downright angry, insisting it was blue. I don't really care either way, it just looks green to me. I can't stop seeing it as green.
If you were to analyze the wavelengths of light the wall, or your notebook, consist of, you'll find a certain amount of blue and a certain amount of green. The thresholds which are detected by our eyes, and the thresholds relative to that where we subjectively determine the dominant color, has high variance.
But people take their subjective perception dead serious, since their perspective is the only one which matters.
It reminds me of the old Gary Larson Far Side cartoon: "Wait, wait, I guess it says HELF"
If you see a sign on an isolated island, what are the chances it really is HELF..
Technically, the color of that notebook is closer to "teal" than "green" or "blue", which is a color kinda halfway between blue and green (fancy that).
From the "uninterested big-box store employee" perspective, though - I would think it to be more likely described as "green", not "blue". Maybe "turquoise" if they know what that is (of course, if they get that fancy with their colors, they just might say "teal" as well).
But if we were looking at this on an RGB scale, it wouldn't be #00F - it would be closer to #0F0 - possible something like #088 - which amazingly:
http://www.color-hex.com/color/008888
Is closer to the color of your notebook.
FWIW - glad it was returned to you, but I don't understand how they could think it to be "blue".
Then again, that whole dress thing - and a whole slew of other research on how people perceive (and describe) colors - definitely show it's possible...sigh.
Your situation specifically brings up the interesting distinctions (or lack thereof) between blue and green throughout history and across cultures. If you haven't already heard of it you should google it yourself, but here's a Wikipedia article that touches on it: https://en.m.wikipedia.org/wiki/Blue–green_distinction_in_la...
I would easily consider that green. Although it appears half way in between the green and blue on a spectrum. I would call it teal.
Personally I'd call that teal but if someone was looking for it I'd accept blue or green as a maybe.