Speier: On the origin of the switch-hitting species

From Alex Speier at Baseball Prospectus on May 17, 2013:

Handedness remains something of a scientific mystery. Its precise roots and causes aren’t known.

But there is a general consensus that the existence of a dominant hand in most undertakings is a useful evolutionary mechanism, helping to explain why it’s been around for so damn long. There’s evidence of the phenomenon in the fossil record dating to at least Homo heidelbergensis, a species that is at least 600,000 years old.

It’s clear that our forebears selected one appendage as the primary one for throwing rocks and spears and bludgeoning enemies with clubs. There was no such thing as batting practice that would permit them to fend off saber-tooth tigers with equal aplomb by whacking them with the right or left hand, no Whitey Herzog school of ambidextrous woolly mammoth hunting.

Evolution resulted in handedness rather than widespread ambidexterity because it is efficient. The brain trains one hand or one side of the body to execute a task and execute it well.

Repeating that process for the other hand? In many tasks, that would represent a waste.


It is intriguing to note that, whereas Bob “Death to Flying Things” Ferguson is believed to have introduced switch-hitting to baseball in 1870, cricket did not have its first documented switch-hitter until five years ago, in 2008. And even with its introduction, the controversial practice remains limited in usage.

But in baseball, hitting handedness continues to defy more general population patterns. This year, of the 469 position players with a plate appearance in the big leagues (through Wednesday), 54 percent were classified as right-handed, 33 percent as lefties, and a whopping 13 percent were switch-hitters.

That spits in the face of typical patterns, given that there’s roughly a 90/10 split between righties and lefties in the broader population. Less than 1 percent of the population is ambidextrous.

So why does hitting defy evolution and broader patterns of behavior?

“Maybe this arena of baseball is such a contrived and unnatural setting anyway that potentially you could throw evolutionary logic out the window,” suggested Red Sox reliever Craig Breslow, who studied molecular biophysics and biochemistry at Yale, but who acknowledges at least some conversational familiarity with evolutionary biology. “Once we’ve determined that we’re working within the confines of an anti-evolutionary system, then we can no longer apply that logic or rationale to the behavior—I suppose.”

Read the full article here: http://www.baseballprospectus.com/article.php?articleid=20609

Originally published: May 17, 2013. Last Updated: May 17, 2013.