Why do cultures always name red before they do blue?

The way different languages view colors is a curious topic. Much has been made of Homer's wine dark seas, and I've seen it claimed that Chinese had no word for pink before modern European contact, while the Russians use separate words for dark and light blue.

Yet amongst all cultures, the historic and pre-historic record seems to show that people named and identified the colors in a specific order: black and white, then red, green and/or yellow, blue, brown, then finally a smatter of purple, pink, orange, or gray. A paper in the latest issue of PNAS, titled "On the origin of the hierarchy of color names," notes:

If a population has a name for red, it also has a name for black and white (but not vice versa), if it has a name for green, it also has a name for red (but not vice versa), and so on.

So why would this be true across all cultures? Why wouldn't someone point and something and call it "blue" before they did "red"?

The researchers believe it has to do with the sensitivity of the human eye to certain wavelengths, and how well we can differentiate colors within the spectrum. They crafted a simulation to recreate a possible explanation for the spread of color names throughout a culture without these descriptors. By using "virtual agents," one of which named a color while the other had to guess what it was referring to, but constrained by the limits of the human eye, the above pattern emerged. That order also corresponds to the colors we see and differentiate the most easily, in descending order.

It's just one theory, but it could explain why red arrives on the color scene before just about anything else.