Left-handed survive evolution of species
by Alexandra Witze, The Dallas Morning News

   (KRT) DALLAS—Prehistoric shamans used to mark the transition from the real world to the spirit world, anthropologists think, by blowing pigments around their hands onto cave walls. These ghostly handprints, which still dot European caves more than 10,000 years later, now serve a less ethereal purpose—telling scientists how many were left-handed.
   New research shows that the frequency of left-handed painters—23 percent—is the same today.
   The work looks at how left-handedness has persisted for millennia, Charlotte Faurie, the French grad student who did the research, says. It suggests no evolutionary disadvantage to being a lefty, as some scientists had thought.
   There’s older evidence that lefties were at work almost as soon as Homo sapiens arose: Wear marks on stone artifacts may signify the presence of southpaws 200,000 years ago. Some of the fossilized teeth of Neanderthals carry telltale marks that indicate left-handed eating practices, Faurie says.
   In caves across France and Spain, Marc Groenen of the Free University of Brussels identified 507 “negative hands,” in which pigment was splattered around a hand by blowing through a tube, spitting, or daubing the paint.
   In 343 cases, he could determine the handedness of the artist; somebody holding the pigment tube in the left hand would presumably have made the imprint of a right hand. Groenen found that 79 of the prints were of right negative hands, suggesting that 23 percent of the cave artists were left-handed.
   Estimates of left-handedness range between 3 and 30 percent of the population. About 10 percent of Americans write left-handed.