Black-and-white vision is a one-dimensional affair. A given shade can get blacker or whiter, but that’s it. Color vision (by which we mean human color vision) has three variables. You can modify any color by changing the amount of red, green, or blue in it. This mix of colors triggers different cones in your eye, creating the perceptual experience of seeing a single, specific shade.
But some animals aren’t limited to three types of cones. Consider birds, whose eyes have a number of advantages over yours. Their eyes are stacked with more cone, and these cones are arranged in larger patches (or in multiple patches) and packed more closely together. This arrangement gives some birds spectacularly sharp vision over long distances. But the most remarkable feature of birds’ eyes is how their cones work. Unlike your eyes, which have three types of cones, birds’ eyes have four or five distinct types of cones.
So what does this mean? Imagine meeting a pigeon and traveling with it to the countryside. Your eyes will collect the same reflected light as the pigeon’s eyes. You’ll see the same scenery. But the pigeon will perceive that light differently. Its eyes will break the rolling hills into a mix of four primary colors, while you translate them to a measly combination of three. For the pigeon, the contrast of certain wavelengths of light will become more dramatic, allowing it to spot details that your eyes miss. The difference is a little like leaping from black-and-white to color vision. Ultimately—and there’s no way around this—the pigeon will get a subtler, more nuanced view of the outside world.
So the next time an interior decorator scolds you for mistaking pistachio green for chartreuse, remind yourself that in the eyes of a pigeon, we’re all color-blind.
Source of Information : Oreilly - Your Body Missing Manual