Why are women not attracted to intelligence?

Women alway say that they are attracted to smarts but when it boils down to it they aren't. I've noticed that when you up the conversation to a higher level they have trouble communicating and lose interest fast. I was talking to this girl that was going to finish first in her cl with a PhD in computer engineering at MIT a few years back. We were talking about random things when she turned to conversation to something in her field. I asked her about the problems we had with trying to train a neural network to detect certain acoustical patterns for a project I was doing at the time. She just started on a tangent and made very little sense. After she embarred herself she wouldn't talk to me anymore. She went form wanting a smart guy to dating some guy that manages a home improvement store that's a bad drunk. This has happened every time I find a so called smart girl that says she looks for intelligence in a guy. It doesn't matter to seem where or how. How come they do this?