I was reading an article on photography the other day, which commented a passage from the book Through the Language Glass: Why the World Looks Different in Other Languages. The author of the book shows how recent experiments demonstrated that different peoples across the world perceive different color hues based on their costumes and needs. Each people has in fact a selective perception of colors: they sometimes can tell apart subtle variations of shades of one color, while ignore altogether different shades of another. As a result, the density, number, and the very names of colors change from culture to culture.
This sounds amazing and you may be thinking to yourself that, besides the famous joke about how men and women see colors, something like that won't likely affect you in your everyday experience. I was impressed to realize the opposite is actually true when I came across Jenkins in my practice of software development. Jenkins was written by a person of Japanese ethnicity, Kohsuke Kawaguchi. As a continuous integration server, one of its core duties is to report the status of execution of jobs and pipelines. Its unique feature is that it associates the color blue to the status of success. You'd normally expect to see green stuff when things succeed. Right? This is a cultural bias.
Jenkins CI server
Let's backtrack for a moment. In Kohsuke's own words, the reason for this is that in Japan, blue means good. They don't refer to traffic signals as red/yellow/green, but actually call them red/yellow/blue. The reason for this is an earlier habit of calling the blue and green colors with the same word (青, Ao) — think of "grue" — which is still reflected in various expressions of the Japanese language as this article brilliantly illustrates. The modern word for green (緑, Midori) was only introduced around the end of WWII during the occupation, and the color it describes is rightfully considered to be a shade of Ao. I like thinking that this originates from the worship of the Japanese for the sea. If you think about it, the sea and waves can appear at times blue, at times green.
Japanese traffic lights
To add more evidence as to how different cultures have a different perception of colors, and associate pleasant or unpleasant feelings to them, it turns out an American team I was collaborating with had installed a plugin that tweaked Jenkins to use green instead of blue for success statuses, the Green Balls plugin. American readers will have already understood what could be wrong with using blue balls to indicate success. In fact, blue balls is slang for an unpleasant condition of male genitals, and as you'd expect, no developer wants to get blue balls as a result of running CI tests.