Not only that, a new study suggests the reason why has less to do with people guessing and more to do with false memories, especially on questions of a partisan nature.
The study was published in the more recent issue of Social Cognitive and Affective Neuroscience. Yeah, it's on my reading list.
As the authors note:
Misinformation, in the form of a demonstrably false belief, is a prevalent phenomenon among American voters and such false beliefs tend to be held in high confidence by voters and are highly resistant to corrective information. (citations omitted)In other words, people believe what they want to believe.
While "educated guessing" is one way to consider the answers people give to political knowledge tests, the authors suggest "the formation of false beliefs" is a more useful way to understand the answers people give. This explains other work that explores why people believe silly stuff like whether Obama is Muslim (my own research area), but also gets into misattribution -- that we attribute positions or events to candidates or political parties that aren't necessarily true, mainly to fit our own predispositions.