This study asks a somewhat different question -- do personality traits better explain this than does education? The answer is, well, read below:
Openness to experience and intelligence are found to be positive predictors of political knowledge and Neuroticism a negative predictor of political knowledge. In both studies education remains the single strongest predictor of political knowledge. Furthermore education can, to a large extent, even out the differences in political knowledge between those with high and low cognitive abilitiesSo education continues to boss around all the other variables, even interesting ones like personality traits such as openness to experience.