>As other commenters here have noted, I found this interesting but a little frustrating. The second color it asks about is clearly cyan (or turquoise). For me, this is like showing an orange screen and asking if it is red or yellow.
This, it commonly gets reposted on reddit and the colorblind sub, but it's basically worthless because most people acknowledge that there is a color between blue and green and forcing them to choose one or the other doesn't give you any valuable information.
The latter tests were all a bit pointless because they were just turquoise, and all looked much the same - a mix of blue and green, so I was pretty much answering based on whether it was bluer or greener than the previous image.
The results said "Your boundary is at hue 179, bluer than 82% of the population. For you, turquoise is green." and definitely if I was judging the boundary on a gradient, I'd have placed the line a bit further to the right.
Yes, very annoying, we know from extensive work in psychometrics that single-item, binary / forced-choice items produce junk responses that are heavily contaminated with response styles (answer in most socially-desirable way, select closest response to mouse/finger, select same response as last time, select random response, etc). Just give people an out ("Diagree with the question / premises", "Prefer not to answer", "Unsure / Can't decide", etc) and make sure you have e.g. a 5-7 point Likert-type scale for multiple items, or up to an 11-point scale for single items.
This kind of site / demo does none of the above, and so can't even be trusted for directional effects (the direction of response may simple be due to the type of people responding, etc).
> most people acknowledge that there is a color between blue and green
For many people, there is no difference between blue and green at all!
https://en.wikipedia.org/wiki/Blue%E2%80%93green_distinction...