bog scientific

for years now I have been conducting a number of scientific projects. This one involves urinals. It so happens in many hotels and other venues there are 3 urinals in a row. I have observed (scientific word) that more than 70% of the time when a westerner enters and the place is empty they will use the urinal to the left or right while more than 70% of the time a Thai will use the middle urinal.
Any comments, ideas as to why. I think the westerner uses the end 1 is to enable the next person the other side with a space betweenand the Thai uses the center one....