Presenting... The Most Interesting Thing I've Read All Day:

...from Wikipedia under the listing for "Red Hair:Biochemistry and Genetics":

"There is some indication that the uncommon pheomelanin/eumelanin ratios found in redheads may be correlated with some corresponding variations in the abundance of other hormones and neuropeptides, including epinephrine (adrenaline), dopamine, and oxytocin. Wolves which are bred to be tame have been found to acquire a progressively paler coat of fur as they become tamer and tamer through successive generations. The speculation is that the cell biology which produces epinephrine (adrenaline) needed for the high-energy fight-or-flight response is linked to the cell biology that governs the relative production of pheomelanin and eumelanin. This finding might explain why redheads are often characterized as having a distinct temperament compared to the rest of the population. This finding might also explain why redheads appear to be over-represented in breakthroughs in the cerebral arts. Socrates, Galileo, and Darwin were redheads, as were Vincent Van Gogh, Mark Twain, and JK Rowling. Redheads also appear to be over-represented in comedy, as well. "




For being a completely un-cited source, I found it amazingly insightful.