This reminds me of a learning technique called "expectation failure". Actually, I think that is exactly what is happening here. We tend to remember things better if we "think" we know the answer, only to find out we're wrong. Failure creates a stronger memory. Some teachers will intentionally mislead their students to a wrong conclusion before revealing the correct answer to make use of this effect. Interesting stuff. :)
I think there was a good lecture about this on Ted.com, but ironically I can't remember my password to log in and find the video, lol.