While I was looking for the butterfly story (below) I stumbled across this gem. Anyone who's been a student, TA, or professor might not find this all that surprising.
Apparently unnoticed student cheating is a significant cause of college course failure. A study in Physical Review Special Topics: Physics Education Research by researchers from the University of Kansas and MIT took on the task of 'copying in college' (kinda sounds like a t-shirt or something). The MIT professor, Young-Jin Lee, spent four years cataloging all of the instances of copied answers in his Mastering Physics class. The homework for this class is administered via a web-based tutor and so the professor could monitor all of the students' homework activities. Here's a don't-get-caught tip: A difficult physics problem is not typically solved in under a minute. Students were also given an anonymous survey about their homework copying habits.
The researchers were able to conclude that (1) students who procrastinated copied more often, (2) students are more likely to copy written homework than online homework, (3) students are more likely to copy late in the semester versus earlier (probably because work loads are higher later), and (4) students who do homework have more success on exams. And because students don't learn anything when they copy they find themselves in a whole mess of trouble when topics get more difficult. A big, fat downward spiral so to speak. Possible solutions to this could include smaller class sizes, more interaction between professor and student, and alternative grading systems.
Find more details here: http://www.sciencedaily.com/releases/2010/03/100318113750.htm