A recent study tested whether people felt like they understood political candidates' positions on a variety of issues like immigration, health care, and taxes. Most people rated themselves as being fairly knowledgeable about the candidates. However, when asked to actually descrive a candidate's position on an issue they felt they understood, people faired much worse than they thought. In fact, after writing this explanation, people rated their actual level of knowledge as much lower than they thought it was earlier.
What's happening is called the “The Illusion of Explanatory Depth”– the observation that people often believe that they understand things better than they do. For example, if you ask people whether they can explain common household objects like zippers, they will say that they can, and then are surprised to discover that there are often big gaps in the explanations they try to generate.
So how does this impact out voting?
[I]t is clear that we often elect politicians without knowing why we like one and dislike the other. We hear very general words applied to candidates like “socialist,” “reactionary,” “dangerous,” or “conservative,” without knowing what those words really mean when applied to a candidate. The results of this study suggest that before we make up our minds about who to vote for, we should think specifically about the candidates. It is good to have passion for the election process, but it is better for that passion to be supported by knowledge.