Bathroom behavior

You're dining at your favorite bistro when suddenly nature calls.
Rushing tothe restroom, you find a row of four empty stalls. All seem
equally clean, are well stocked with toilet paper, and feature a similar
assortment of amusing graffiti. Which are you most likely to
choose?

a) one of the two middle stalls

b) one of the two end stalls

c) whichever is closest.

To discover the answer to this bit of toilet trivia, Nicholas
Christenfeld, Ph.D., a psychologist at the University of California, San
Diego, monitored how often the men's room custodian at a California beach
had to replace the toilet paper in each of the bathroom's four stalls. It
turned out that 60 percent of the used-up rolls came from the middle
stalls, rather than the 50 percent you'd expect if choosing a toilet were
simply a matter of eenie-meenie-minie-moe.

But a mania for the middle extends well beyond the rest-room door.
Faced with four rows of crackers on a supermarket shelf, two-thirds of
shoppers will grab a box from one of the center two rows. And if you draw
three circles on a sheet of paper and ask people to mark one with an X,
half will choose the middle figure.

If there's no difference between several items we can select, why
do we avoid the ones on the outside? This habit may be a mental shortcut
we use in situations that aren't worth thinking about, says Christenfeld.
The center of something is often safer than the extremes; in reaching for
a can of tomato paste from an end row we might accidentally grab the jar
of sauce sifting next to it. So by mindlessly picking the middle item we
save our brainpower for more important concerns.