You've probably heard the line from John Stuart Mill that "while it is not true that all conservatives are stupid people, it is indeed true that most stupid people are conservatives". Well, now there's a study that seems to support this:
Surprisingly, this fundamental question has never been examined scientifically-until now. Psychologist Ian Deary of the University of Edinburgh realized he could explore the link between IQ and values using a very large existing data base on kids who were born in 1970. These boys and girls, more than 7000 of them, had all taken IQ tests at the age of ten, so he was able to sort out the bright kids from their duller classmates. These kids had then been tracked and interviewed repeatedly for two decades, so there was a rich record of not only their education and work lives but also their basic attitudes and beliefs: on race, gender equality, the environment, the sanctity of marriage, and so forth. In short, Deary wanted to see what kind of people they turned into at age 30, as they stood on the cusp of the 21st century.
Not to put too fine a point on it: The smartest kids turned into the most broad-minded and progressive adults. For example, the most intelligent kids turned out 20 years later to be much more tolerant of other races. They were also much more supportive of working mothers, rejecting the notion that pre-school children will suffer without a stay-at-home mother. In general, the sharpest kids came to embrace much less traditional moral values and were much more apt to challenge authority. They were also much less cynical as adults, more trusting that the political system can do good.