The reason people would go for box A2 in both cases (even though it had moved, is because it is not an outer edge.

People don't tend to go for extremes unless there is a very good reason, and people tend to try and hide things amongst other objects, i.e. in the middle.

Personally, I chose to hide it in A3 in the first example, as it felt the most wrong, but would take from A2.

The middle A box is simply the most anonymous - it isnt at either end and it isnt B.

When you watch people in similar situations it is often that when for example they are asked to choose from cards that are spread take one in the middle. Since in the box problem is a part of enemy-situation as I would call that, B sticks out too much but A is more "hidden" in the whole thing. So it doesn't surprise me very much that people go for the middle A.
I would have put it into the first box or the last one and expected that people look into the middle ones and most likely A. :)

I think it's the "anonymity" of Box A2. It is the least unique choice (there are other As and there are other middle boxes) and therefore seems less significant, somehow lost in the noise a little. This makes it an attractive hiding place.

my idea was to hide it in a3 (the last box) and look in a2 (the one you pinpoint as most commonly used).

I suppose that is the best place to look since more than not put it there.

The logic of it is something like what the person suggested, it (a2) is the one box that is not "distinguished" by being on an end or having a different letter. So it seems the most random-feeling.

I believe this comes down simply to the same factor on both hide and seek. In hiding something in good faith, the urge is to pick out a spot that is in no way conspicuous. "On the end" and "a different type" are all conspicuous choices. In fact, most responses in favor of other choices mention this fact, and in choosing against eliminate it as too conspicuous in its inconspicuousness...

I would have chosen B to hide it because this is the most obvious one, so in my mind the one people would avoid the most, it’s a bit like hide the money in the open.

A hilarious study and set of responses! It tells how similar we are in deviousness, and it's that similarity that gives others power to anticipate and second-guess us. We can psychologize it. Hiding it up front is seldom sought as it's akin to telling the truth, like "being too up front" about the issue. Putting it in the different box seems like it makes it too obvious or "conspicuous". The last box is too far back, and like the front, is too "out in the open". We are left with the box about which we haven't raised any reasonable objections. When looking for it, this same reasoning works in the other direction - we anticipate their lie by modeling it within us. Were there more A's, the distribution wouldn't have been so obvious for the inner boxes.

I'm curious to know whether anyone decided to take the loophole and hide $25 in each box :).

I also picked in the original scenario A3 to hide and A2 to pick. My reasoning is based on B... you're immediately drawn to it, but then you know since it stands out, it's too obvious. So where do you pick? Well, A1 and A2 are both "adjacent" to B, so you're most likely to go there first (either looking or hiding). Since A2 is in the middle, people prefer it. So that's why I'd look there. I'd hide it in a place that is least likely to be looked at in the above scenario, which is A3, since it's on the end and not adjacent.

The statistics only partially bear this out, though, as more people would look in A3 than A1. But in the second scenario, where A1 is now the "end" box not-adjacent to B, A1 is safer, but also a lot more people hide there! So obviously there's more to it than just what's not adjacent to B, but I think that's a large factor.

Bruce

I chose B in both instances. As the hider, I figured who would think to look in the obvious standout ? They surely wouldnt think I would hide it in the most blatantly different box. As the seeker I chose B because it seemed like the last place anyone would look, therefore a great hiding place.

I would chose a1 in any case, anyone who came by would chose a2 simply because it is not on an edge and it feels hidden. Noone would pick a1 because they reason it was the least likely picked for it's first spot. In other words, it is the first, and noone picks the first for some reason. Yet when picking the a2 is the most chosen for some reason.

When I first looked at the boxes (without reading the question), I was immediately drawn to A2 and for that reason I could not possibly choose to hide it in that box as I assumed others would also like A2. I decided to hide in B because looking there goes against instinct (it's like if someone had put a $ sign on it...)