Why is it that brunette is thought to be smarter than a blonde?

That is a stereotype

They are? I have 4 kids that are blonde one is an attorney, one is an accountant, the other 2 have not figured out what they want to do.

It's probably just a stereotypical remnant of an old comedy skit. Which leads to another question of who/which comedian started this nonsense?

Just a simple false statement.

There's two pieces of false information in here.

1. Hair color has nothing to do with such a thing.

2.We don't have certain smart people. We are all smart. Everyone is just smart in something different than somebody else.

Albert Einstein slayed science, wasn't he smart ? But he couldn't keep numbers and names in his mind and couldn't drive his whole life, and he was a slow talker and learner during high school. 

They are? I'm a blonde, and my best friend is as well.  We are both straight A students, I topped English (although sometimes you wouldn't know it because of my horrible grammar on here, but I'm not THAT fussed...), and she topped Maths.  My other friend, whom is also a blonde topped Instrumental Music.  My only brunette friend who topped a subject (I have a lot of brunette friends) topped Chinese, Music and Drama, and I have a brunette friend outside of school who skipped grade 8, and another who topped English and Japanese.  So your hair color doesn't determine your intelligence; it's just a blonde stereotype because blondes are prettier than any other hair color :-D  (jks)

Wow...Either you don't get out much or you believe the media hype about dumb blondes. My husband and I are both blondes, and we both have IQs in the 140s.

And just so you know, blondes don't have more fun either. Your life is what you make no matter what your hair color, or any other physical feature.