This week’s Economist reports on a study by Faurie and Raymond — to appear in the Proceedings of the Royal Society; PDF pre-print available from Faurie’s web site — that looks at why left-handedness persists in human populations. The authors hypothesize that in violent conflicts between left- and right-handers, that left-handers enjoy a competitive advantage, since their opponent won’t be used to their style. This is, of course, not a new hypothesis — it’s an obvious extension of the empirically-observed advantage lefties have in sports such as baseball, fencing, and boxing. What’s new here is that the authors took the next step: they hypothesized further that if this was the reason why left-handedness was maintained in human populations, then the frequency of left-handed individuals should correlate with the amount of violence in a population. The authors had to constrain their data to “traditional societies”, because firearms remove handedness from the equation, but when they looked at the data, they did find a strong positive correlation between murder rate and proportion of left-handers in the population. Almost 23% of the famously violent Yanamamo are left-handed, for example, compared to only 3.4% in a pacifistic group in Burkina Faso.
I am, of course, left-handed, and that’s why I found this article interesting. But the thing that tickled me enough to post about it is the penultimate sentence of the Economist article:
While there is no suggestion that left-handed people are more violent than the right-handed, it looks as though they more successfully violent.
Anyone wondering about holiday gifts for me: a tee shirt reading “left-handed, therefore more successfully violent” will be accepted with profuse thanks.
(The original Economist article is online, although you’ll have to be a subscriber to see it.)