I find it interesting that we can study human behavior by watching the use of a dual-roll toilet paper dispenser. My unscientific analysis assumes three characteristics of human behavior:
We are creatures of habit,
We tend to follow the path of least resistance, and
We don't want to be the one that changes the toilet paper roll.
Phase I - A Fully-loaded Dual Toilet Dispenser
My study begins by loading both spools of a dual toilet dispenser and watching how the toilet paper is depleted over time. I noticed that the spool closest to the user begins to be depleted first. This supports my assumption that we follow the path of least resistance. An interesting phenomenon happens when the closest roll gets dangerously low. At that moment, the closest roll stops being used and the furthest spool starts getting depleted. Apparently the threat of having to change the paper roll is too much and the path of least resistance is to reach further for the other roll. This continues until the furthest spool gets dangerously low. This supports my assumption that we don't want to be the one that has to replace the empty roll.
Phase II - Both Spools are Dangerously Low
At this phase, both spools get evenly depleted and dangerously low. Finally the spool closest to the user is completely used up. At this time, the closest spool does not get replaced but rather the furthest roll gets depleted until it is completely empty.
Phase III - Both Spools are Empty
Finally, both rolls become empty and it seems this is where I come in. Clearly the only choice left is to replace the rolls and begin the analysis again. As I know we are creatures of habit I can be assured of a similar outcome.