A short article in the October issue of Discover explains that sometimes being color blind isn't a bad thing. It was discovered that color-blind capauchins (a species of monkey native to S. America) were more successful at hunting camouflaged insects than capauchins with broader color vision. One hypothesis is that color-blindness actually helps improve the ability to notice differences in texture and brightness, thus being able to better detect camouflaged insects. As a hobby artist, I find that black and white photos sometimes show me more than a full color photo, especially in looking for differences in contrast or brightness - sometimes full color sends too many signals to the brain.
So, in addition to possible alien sentient beings able to perceive only or mainly in the UV range (see previous posts with the tag "alien senses"), or in the infrared, some aliens may see within our range, but be color-blind compared to the average human. Of course, we woul'd be UV-blind (though there have been rare instances of humans being able to see partially into the UV range).
What drives color range?
Sex and food primarily, and possibly detection of enemies. For instance, some researchers feel that first color vision arose because those who evolved the ability to see color were better able to distinguish ripe fruit. As the primates developed, and then improved, their ability to see red and orange, the primates began to develop orange and red hues to their hair and skin (or maybe more accurately, those few primates that had orange or red hair stood out from the others and thus were favored by the primates that were more successful in finding ripe fruit).
Color Tracking, Sports, and Church
Interestingly, humans can normally only keep track of three items at once, but if groups of items are of the same color, then we can keep track of three groups, or sets, of items, and thus keep track of many items at once - as long as the items are grouped in no more than three sets of colors (thus, one reason for team uniforms). Not sure what the benefit is of only three. Why not four or five? But at least our minds can use the "trick" of color to get around that limitation somewhat. Maybe humans hunted packs of animals in packs themselves, but also needed to keep track of their human pack leader (the "alpha wolf"). Thus, team uniforms are very advantageous for the spectator: with the two opposing teams in different colors, and the referees in yet a third color, the spectator can keep track of what is going on far better than if everyone wore whatever they wanted, with no player having the same color scheme as any other player on the field. Sports may not have been the evolutionary pressure to develop this ability to track three sets based on color, but instead an example of how the modern mind takes advantage of the situation.
But if we could answer the question, why three, we may be able to determine the conditions needed for an alien species to develop the ability to track four or five (or just two). The ability to track different items will affect the alien civilization's social, cultural, and theological realities; think about the three again: humans have trouble tracking more than three items at once, and three seems to be a holy number for many of our theologies - coincidence? Maybe for aliens that can track four items at a time with ease, four would be their common holy number. And maybe they would have games involving three teams at once.
American Institute of Physics. "Tracking Your Team." Science Daily. 1 December 2006. 25 November 2007. <http://www.sciencedaily.com/videos/2006/1202-tracking_your_team.htm>
Barone, Jennifer. "The Upside of Color Blindness." Discover. October 2007. 17.
John Hopkins University. "What Are Uniforms Uniform? Because Color Helps Us Track Objects." Science Daily. 24 July 2006. 25 November 2007. <http://www.sciencedaily.com/releases/2006/07/060724105951.htm>
Ohio University. "Color Vision Drove Primates To Develop Red Skin And Hair, Study Finds." Science Daily. 25 May 2007. 25 November 2007. <http://www.sciencedaily.com/releases/2007/05/070524155313.htm>