Are smart people clean or dirty? Haven't you seen both images, right? The squeaky clean George Will on the one hand, and the professor who looks like he slept in those clothes on the other. General Social Survey interviewers rated the cleanliness of houses along with asking a zillion questions, and here is the mean IQ for each rating:
Very clean 101.6
Not very clean 92.5
Very clean 91.7
Not very clean 82.2
For both races, smarter people tend to be cleaner. This is a bit of support that virtues tend to run together. Notice, however, that the mean IQ for whites jumps up a bit among the "dirty" so the stereotype of the brainy white slob is probably true for a minority of smart people.