h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

Perhaps the most convincing argument for ‘under’ is neatness. But for a roll to become untidy the loose paper must hang down at least one whole sheet. Firstly this is easily avoided by average care and attention to the task of using the toilet roll, and secondly, messily hanging paper is equally unappealing hanging from the back (although there is a little more margin for error). Perhaps that last point can explain the gender differential in this conundrum. Women’s lower average height, and indeed more time spent sitting in the relevant area, would leave them at a more discerning angle to see hanging paper.

For me, the clinching factor for the case of ‘over’ is thus: It is fairly common for the ‘live’ end of the roll to become flush with the rest of the roll (much like awkward Sellotape®). To rectify this problem it is necessary to spin the roll until the end is released; this is done by a ‘swiping’ of the hand (much like the cat in the original argument). When the roll is hung under, this required swiping is of course upwards on the facing side of the roll. This upwards swiping can cause instability in the holder arrangement, and may even knock it clean of the wall. A downward swipe is much more controlled and easier to carry out. A particularly stubborn roll can lead to vicious spinning in both directions. To avoid this, perhaps a national convention need be adopted to ensure only one direction of spin is necessary to find a loose end of toilet roll.