The illusion of explanatory depth.

From MindHacks post The best way to win an argument :"A little over a decade ago Leonid Rozenblit and Frank Keil from Yale University suggested that in many instances people believe they understand how something works when in fact their understanding is superficial at best. They called this phenomenon “the illusion of explanatory depth“. They began by asking their study participants to rate how well they understood how things like flushing toilets, car speedometers and sewing machines worked, before asking them to explain what they understood and then answer questions on it. The effect they revealed was that, on average, people in the experiment rated their understanding as much worse after it had been put to the test."