Like many debates in psychology, this one pits congenital, fundamentally genetic, explanations against explanations that rely on environmental determinism. Psychologists in the former camp think people are born with ingrained ideas about how hues are grouped. They believe the brain is preconditioned to pick out the six colours on a Rubik's cube whatever tongue it is taught to think in. The other camp, by contrast, thinks that the spectrum can be chopped into categories anywhere along its length. Moreover, they suspect that the language an individual learns from his parents is the main explanation for where that chopping takes place.Read it to find out why.
As with most nature-versus-nurture debates, compromise seems in order. Two papers published in the Proceedings of the National Academy of Sciences suggest where the middle ground lies.
(Never mind the implications.)