Being a southpaw (what can I say the devil’s inside me) I found this to be highly intriguing.
1. 8 of the 44 presidents have been left-handed. Almost double the incidence of left-handedness in the general population. Al Gore and John McCain were both southpaws, as well. Since 1974 only Jimmy Carter and Dubya were righties.
2. Favoring a particular hand is unique to humans. Neither chimps nor gorillas favor a hand.
3. The incidence of left-handedness seems to be constant throughout history and may have developed congruent to the other distinct human trait – language.
Some of the oldest evidence of left-handedness comes from Kenya, where of a 500,000 year-old cache of 54 stone tools made by one of our pre-human ancestors, six (or about 11 percent) were chipped using the left hand. Similarly, Neanderthals working with meat and stone tools more than 150,000 years ago left marks on their teeth at left and right angles – indicating opposite hand use – in almost perfect proportion with today’s 9:1 ratio.
4. Whereas language is usually processed in the left-hemisphere for right-handed people and in the right-hemisphere for left-handed people, left-handed people also process some language in the left-hemisphere — providing for the possibility that some sort of evolutionary advantage exists for lefties.
Though a specific left-handed gene has yet to be found, the trait to choose one hand over the other is likely inherited, agree scientists. Left-handed parents are far more likely to produce left-handed children, and those children appear to begin favoring that hand in the womb, according to a 2004 study on 10-week-old fetuses.
More recent research suggests that, while developing, the two sides of the brain actually “fight” for specialized control of certain functions, such as handedness, with the left side (which controls the right – are you following?) more often coming out on top.
To my knowledge in my family besides myself, my mother and grandfather were both lefties. I suspect my father is ambidextrous, since he was a switch-hitter in baseball, though this has never been confirmed.