The fine folks at Pew pushed out a tweet this morning pointing to their survey question asking people what they know about the so-called fiscal cliff. Only about a quarter of the folks surveyed "say they understand very well what would happen if the automatic spending cuts and tax increases were to go into effect in January." The table is below.
Keep in mind this is self-perception of knowledge, not actual knowledge. The difference is significant, because as we all know, some folks overestimate how much they know about a topic (think of your crazy uncle at Thanksgiving who is an expert in everything). Actual and perceived knowledge do correlate, but not perfectly. That's the fun part, studying the folks individuals who think they know a lot but actually don't. They tend to be the ones more emotionally involved but who don't consume a lot of news -- or who rely heavily on pseudo-news such as talk radio, etc.