Reading through More of the Straight Dope, I came across an interesting section based on the question as to whether early man could only see three colors.
Most of the evidence that ancient man did not have the same level of color perception that we do today comes from both artwork and literature of the time. For example, the naturalist Lazarus Geiger put forth a couple of theories based on his studies of Greek literature, the Vedic hymns, and other ancient writings, as well as the fact that most artwork from the period only contained four colors: black, white, red and yellow.
Many scientists today dont quite accept this as fact by any means, but there are some interesting rules that have appeared in studying the patterns of ancient languages:
- All languages contain terms for white and black.
- If a language contains three terms, then it contains a term for red.
- If a language contains four terms, then it contains a term for either green or yellow (but not both).
- If a language contains five terms, then it contains terms for both green and yellow.
- If a language contains six terms, then it contains a term for blue.
- If a language contains seven terms, then it contains a term for brown.
- If a language contains eight or more terms, then it contains a term for purple, pink, orange, gray, or some combination of these.
For more information, check out the original piece on the Straight Dope website.