jevans@MIT.EDU writes:

>Anime hair colors are a convention...they're there for the same reason people
>use the sweat bead or SDness...the characters aren't supposed to really know
>that their hair is that color. It's an abstraction barrier (to quote my CS
>lecturers...)

Somewhat relevant quote from Dr. Slump, drawn by Toriyama Akira, who sometimes
puts himself in the series:

(Norimaki Senbe's father has just come down from the country to visit him.
A *very* rural country where ball-point pens are the neatest thing, by the way.)

Father: Who is this, Senbe-kun?
Senbe: Midori? *reddens* She's my wife.
Father: Oh, wow!  You didn't tell me you were married.  She's awfully
  fluent for a foreigner.
Senbe (falls down): Uh, no, father, she's Japanese.
Father: Really?  With that hair and eye color?
Toriyama (with giant bead of sweat): *sigh*...country folk...