PEW Research has a computer survey (nonrandom) on political IQs available here. If you want to do the survey, I suggest you do it before you click on the picture above. Generally men and those with the most education do better on the survey. I wouldn't have guessed where older or younger people would have out preformed each other. Older people seem to be much more likely to correctly identify people and younger people seem more likely to identify flags and symbols.
Yet, these are trivial questions. If only 57% can identify China's flag or 55% can identify who is the attorney general, I can only imagine that a much smaller percent would correctly guess the content of a particular law.