The Sociology of Libraries, Part 2

In my library we have return chutes so that people can return books without having to come into the library. There's three chutes - two are for books and one for AV. They're clearly marked. These chutes lead into the returns area where we put a book bin under each chute. I just wanted to set the scene.

Because there are two chutes for books, you would think that book returns would get distributed evenly between the two chutes. However, this is far from the case! For some reason, most people use the middle chute to return their books even though there is a perfectly good chute right next to it too. While this doesn't really matter during the day, it does make a difference over things like the Easter weekend, which, when I went in to clear the returns on Monday, meant that the middle chute was completely packed and the one next to it had some books in it, but less the half of the other one.

Why is this? Why are people drawn to the middle chute? Are they trying to outguess other returnees who may put their books in the chute closest to the stairs leading to the library? Are they compulsively drawn to the AV chute and this is the next best thing? They can't see how many books are in each bin (if they did, they might change their minds), and there's nothing to guide them except for the (identical) signs telling them where to put books or AV.

Because I've noticed this, it's really annoying me. Everytime something is returned though the middle chute I want to run out and ask them why they've used this chute. I'm convinced now that there's some sort of conspiracy between staff and patrons, which I'm not yet privy to, about the use of the middle chute. The other option is that it is completely arbitrary and I'm reading far too much into the whole situation. I'm (almost) happy to admit that this is the case, but it won't stop my curiosity and increasing irritation at the lack of a better explanation!