There is actually evidence that naming colors helps us differentiate them. NPR, Radiolab had a fascinating article on color. It started out pointing out that Homer uses some strange descriptions for color. He refers to violet sheep, and wine-dark sea and oxen. Both Honey & faces 'pale with fear' are described as green.
http://www.radiolab.org/story/211119-colors/It turns out that blue isn't ever mentioned in the Oddessy. In fact, when we trace linguistic roots, blue is one of the last colors that is ever defined by cultures. There are a couple of reasons theorized by this, such as its rarely occurring in nature, and comparatively hard to manufacture artificial blue dyes.
But when anthropologists study current cultures which still have no word for various colors, when shown, for instance, a monitor screen with clearly defined colors (I think the example they used was blue & green) the individuals couldn't even tell them apart. Given 4 squares, 1 green and 3 blue, they reported all squares were identical. (cellular and biological differences were ruled out)
The phenomena is apparently present with us too. Another piece in the same episode they explore tetrachromes, women who have a 4th type of cone in their eye, theoretically able to see a wider spectrum of color. They were unable to find one until they came upon one woman who could indeed differentiate this supposed color difference that none of the other test subjects could. This woman however, was also an interior decorator so worked extensively with color. Then they tested an (male) artist and he too could differentiate this color difference that no one else could. (men CANNOT be tetrachromes) So in the course of working with color, he had trained his brain to further differentiate color than most 'normal' people can. It wasn't a cellular thing, but rather a brain-training thing. Working backwards, it wasn't that the tetrachromes didn't exist, but rather that most were not trained to see the additional color difference.
http://en.wikipedia.org/wiki/Tetrachromacy