According to a University of California study, anyway. They found that of 156 female students the blondes were "used to getting more attention and being treated better by others." Which made them more aggressive and determined when things went wrong.
...he suspected that blondes existed in a "bubble", where they had been treated better than other people for so long they did not realise that men, in particular, were more deferential towards them than other women.
He added that:
They may not even realise they are treated like a princess.
This entitlement he said, makes them more willing to "go to war" when something goes wrong. Look, Aaron, in time these wounds will heal. It won't matter so much that she always criticized you when she was in a bad mood. You'll find someone who loves you for who you are.
Anyway, other researchers pointed out that the sample is small, and that blonde women actually earn less than their counterparts.