Myriad questions present themselves about the two toilet stall studies.
The most obvious: was it a men’s or a women’s lavatory? One would expect that the bathroom behavior of men and women is quite different. Second, neither of the environments selected is at all typical. While an antarctic outhouse might not be as malodorous as a tropical one, the concentration of unpleasant smells might tend to drive users to the outer stalls. Conversely, a public lavatory at the beach might be partially exposed to outside observers.
The time that the user expects to remain may also be a factor. The antarctic facility is more residential, and hence a place where one might seek solitude for reading, whereas this would be much less probable in the California case. [EDITOR’S NOTE, based on an angry note from an entirely different investigator: temperature may contribute opposing effects.]
Finally, I question the measurement technique in both cases. Both methods measure the aggregate utilization, but give only a hazy clue to which stall will be chosen when one or more stalls are occupied.
Clearly this is an area that calls for much more careful research. Perhaps an informal look by Professor Trinkhaus is in order.