This is very very incorrect story about blonds.
In general the natural hair color of a Polish female is what you could call dark blond
Not true. Polish females have hair color (natural) from dark-blond, light-brown and darker. Im a brunette naturally. But in my life I have been a blond naturally too. As my hair changed colors over the years, from born with black - blond - and darker darker darker...
So first, most girls in Poland are dying hair blond and secondly, if brunettes go blond, all of sudden they are "dumb"... that in itself is dumb....
How many Dumb red-heads there are in the world, and brunettes... hair color, eye color and skin color have nothing to do with intelligence.