I always put up that picture of Einstein with his tongue out up before a date. Puts people in the mood.
I guess that's just because what you put into a situation ultimately becoming the result. As the great luminary Megan Fox once said "If you eat Chinese food, your farts come out like Chinese food. If you eat Mexican food, your farts come out like Mexican food. And milk, it’s like—you can smell the warmth in the fart. My wardrobe on Transformers always smells like farts, and I have no idea why."
As someone else has already said, higher income people have the means to take care of themselves, so they're going to be "better looking" on average if the sample is big enough, and given that they probably all went to at least high school, they're going to have higher levels of cognitive performance. It's nothing big.