I was on the math team one year in high school (either sophormore or junior; I don't remember which). All five of us on the team were left-handed. Of course, we were also all white, myopic, male nerds (though I was also on the football team), so it may have been a self-selecting group. ..bruce..

I have always been under the impression that left-handedness is correlated with technical (math/science/engineering) abilities. I estimated that the student population at MIT was about 1/4 lefties when I was there in the 70s. My engineering group in Silicon Valley was about half lefties. I do seem to recall real studies that back this up, but I'm too lazy to try to find one.

Anyway, it may well be the case that technical fields pay better on average than non-technical ones. But a 13% or 21% average difference surprises me. A difference that big must be due to the fact that we're handsome, charming buggers whom people are happy to give big raises to...

Well I just asked the wife what she makes of this tidbit, and she immediately reasoned as follows:

a) Men are the more aggressive of the sexes (brief detour into Men Start All Wars, then, Rumsfeld Is An A**hole, until I reeled her back in). But they often have better problem-solving skills. Couple that with the extra dollop of creativity from right brain dominance and it makes sense a male southpaw ends up making more moola than a rightie.

b) Women's brains possess more connections in the tissue joining the right and left sides of the brain than men's brains (I took her word on this), making them better at tasks involving verbal expression and emotional perceptiveness, and reducing the effect of dominance of one side of the noggin. This apparently is also the source of creativity and it levels any possible earning differences in a woman being a leftie vs. a rightie.

"So are you saying that all women are more creative than right-handed men, and left-handed men are at best as creative as women?", I demanded.

"Yes."

IIRC, there are a lot more left-handers than there used to be, because the left side of the brain tends to be more quickly affected by hypoxia & anoxia; a much higher percentage of difficult birth babies survive than used to; they are disproportionately left-handed. This is one of the explanations, at least.

I once took a linguistics class and noted that 5 of the 8 men in it were left-handed. Hardly definitive, but it made me wonder if left-handed men were more likely to have greater language skills, that might lead them to the study of language.

I offer the possible explanation that left-handed guys rule. Woooo!

But that is less than entirely scientific, so for appearances sake I throw out the question of whether earnings differentials were noted without regard to career choices or instead were placed in some kind of context. In other words, do we know the extent to which higher left-handed earnings reflect a higher proportion of left handed males entering professions that tend to pay more?

Unforunately, the results are probably skewed by the inclusion of Johan Santana, Randy Johnson, Ken Griffey, Jr., etc.

More importantly:

What does this say about the political left vs. the political right?

So, how come I'm out of work, then?

I remember learning (far too long ago for it still to be reliable) that there are two kinds of lefties: genetically predisposed (i.e., with a family history), and as a result of developmental or birth events or trauma (e.g. the hypoxia mentioned by a poster above). The latter sort tend to be "inverse right-handers", that is, their brains are strongly bilaterally differentiated, but in mirror-image mode. Genetically predisposed lefties have much more diverse and uneven brain bilateralization, tend to ambidextrousness, and the exact location of their language areas varies considerably.

If this is (still) considered true, then all statements about "average" lefties are likely to be confused, since they lump together two quite different populations.

All I can say, though is "left on, brother" (while noting that I'm right footed and right eyed...).

There's a fascinating book "Right Hand, Left Hand" and a web site of the same name that delves into the subject. (Won the aventis prize for science books.) The professor ties handedness to the structure of the universe, as well as the unification of Italy.

Does Larry Summers know this?

It pains me to see commenters repeat the old saw that difficult births result in left-handedness. It reminds me of those French researchers who claimed lefties don't live as long as righties, based on their analysis of baseball players. One of the researchers also stated that left-handedness was largely due to "brain damage". The researchers' studies were held as junk science.

The study in question can't be assessed by the glib conclusion presented, the parameters need to be examined closely for other possible factors. It's foolhardy to accept any study of lefties, when there's no accurate database that can even state unequivocally how many of us there are.

That leaves subjective analysis, and I'm willing to go along with Curt. Handsome, charming buggery is the secret of our success.