lefties

[Elizabeth Bates]

As a left-hander myself, I've also kept track from time to time of
the distribution in various settings.  As a female leftie, I may
have paid more attention to the distribution in females.  It had
struck me that the number of left-handed females was particularly
high in academic settings.  One year I was at a conference in
Cambridge, and for irrelevant reasons, was carrying around a set
of the binomial tables with me, which permit you to look up the
probability of obtaining a given distribution by chance, if you
know the baserate in the normal population.  Assuming a generous
17% baserate for lefthanders (and of course that is a problem in
its own right, because handedness really isn't a dichotomous variable,
but a "J-shaped" distribution with lots of points in between),
it did turn out to be the case, at a level of p < .05, that there
were more left-handed women at the conference than we would expect
by chance.  The same was not true of men.  I haven't bothered to
replicate this calculation, and wouldn't be in the least surprised
if it doesn't replicate.

By the way, my European friends all have the impression that most
Americans are left handed.  Apparently the suppression of left handedness
lasted longer in Europe, so the baserates of EXPRESSED left handedness
may be a bit high in the U.S.  My friend Virginia Volterra remembers
catching her mother-in-law whispering to her grandchild "Grandma will
give you a cookie if you use the good little hand....".  -liz bates