How to study?

At uni we give students access to past test papers.  They are all multiple choice questions.  And sometimes I don't put the answers up, so that students don't know whether they have a question right or not.  Because I figure that I really want them to absolutely convince themselves that they are right.

But when I do that the complaints roll in.  Apparently I'm hurting their study if I don't tell them the answers. 

Anyhow this year I've published the questions from last year, but rather than just put the pdf up, I've made it an online quiz, and haven't mentioned that the questions are from last years test.  The students do the quiz, and get a mark.  They don't find out which answers are correct, at least not for a week or two.  Somewhat hopefully I'm expecting them to go to the online forum and argue about which answers are correct.  But why do it like this?

Well the normal way of studying is to do a past test question, and decide that "C" is the correct answer.  Then you look at the actual answer and discover that it is "D".  So you convince yourself that you understand why "D" is correct and "C" is not.  And you move onto the next question.  Actually for many students I'm gilding the lily.  They just look at the question, look at the answer, and think, "Yeah, that makes sense".

Can you see why I hate these approaches?  Because a student can do it this way and not have learned much.  Not have really, really worked to understand.  I'd prefer them to actually think about the problem.  And not telling them the answers straight away, that should push them to think.

The other thing about making it an online quiz is that they get a score.  And if its a low score, that should come as a shock. A shock they won't get if they just look at questions and answers and think, "Yeah, I get that". So I'm trying not to let them kid themselves that they are doing ok when they aren't.