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Alex Speier covers the Red Sox for His playing career reached its zenith when he started a game-winning rally by getting beaned. He rarely sleeps, has many questions, and ventures few answers, while demonstrating proclivities towards sesquipedalianism, circumlocution, and the unintentional misuse of foreign languages. Though he is terrified of 140-character communiques, you can follow him on Twitter @alexspeier

Young Maxwell Speier, newly turned 3 years old, has discovered that a Nerf baseball bat and ball can capture his attention for approximately six to 10 flips. He displays a genetic predisposition to enthusiasm in the undertaking and echoes his father's characteristic proclivity to swing and miss (still enthusiastically!) in volume, considering it a minor triumph if, at the conclusion of an unfettered and ill-timed swing, the ball should bonk him in the chest or face.

"I hit it!" he shouts, leaping up and down with delight as the orb ricochets off his nose.

Yet as striking as those similarities to his father at a comparable age (or, for that matter, any other age) might appear, there is a distinction. Max seems inclined to wield his Lightning McQueen-decorated cudgel from the left side of the plate, in contrast to his father's ineffectual approach as a right-handed hitter.

And so, the unathletic father wonders: Will Max continue to drift towards left-handedness with a bat? Or at some point, might he reimagine his approach and hit from the opposite side of the plate? Or—more puzzlingly—will he join the subset of players who choose offensive ambidexterity, going down the strange and little-understood path known as switch-hitting?

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.

“Once you start getting into tasks that can be done discreetly by one hand or the other, it makes sense to focus on the one hand and train your brain to interact with your arm in one specific manner. It just simplifies and increases the efficiency of doing that task,” said Dr. Neil Roach, a biological anthropologist at George Washington University. “If you just think about throwing, you have essentially the same arm controlled by the same brain on both sides. But your ability to throw incredibly quickly and do other things such as swing a bat with the same precision is really affected by your muscle memory.

“You can have pitchers that can throw a baseball with a dominant arm, let's say their right arm, at 90 mph, but if you force them to throw with their left hand, their performance is going to drop hugely. So this is a matter of muscle memory and training.

“The advantage of choosing one side over the other is that you train those muscles and use your training in an efficient way to get the best bang for your buck from one side of your body, training your brain to interact with the muscles on that side of the body to produce a specific action.”

Switch-hitting, then, represents a conscious decision to defy the efficiency borne of evolution. Instead of committing all of one’s time to developing, say, a right-handed swing that will yield success against pitchers of either handedness, players first must train themselves to hit from their non-dominant side and then must maintain and refine the skill of hitting from both sides of the plate.

In other words, they’re not only trying to create a skill that they don’t have, but they’re also doing so at some cost (one would think) to the time they can invest in sustaining something they’re already really good at. If practice time is zero-sum, then there may be a degree of robbing Peter to pay Paul—trying to cultivate a skill that comes unnaturally by sacrificing time spent nurturing an already-present talent.

“Individuals that can dexterously do multiple tasks in different hands are in good shape. It's just a question of, what is the cost of generating that ability to similar degrees of effectiveness?” said Roach. “I would suspect that there are a number of folks who could have some minor success switch-hitting but who never switch-hit because they wouldn't necessarily get a good bang for their buck for doing it. It's something you could train up on, but it's hard to say if you'd meet the performance thresholds in order to make that training worthwhile.”

Viewed through another lens—the Red Sox went through a period a few years ago when they had three switch-hitting catchers: Jason Varitek, Victor Martinez, and Jarrod Saltalamacchia. All three seemed like they were in a perpetual state of having completed boot camp, drenched in omnipresent sweat before games, while fulfilling the seemingly endless requirements of their preparations.

(The three represented an interesting study in the nature of handedness: Varitek was a much better hitter right-handed than left-handed; Saltalamacchia has considerably better career splits as a left-handed batter; and on a career basis, Martinez exhibits an almost imperceptible distinction between his performance from the two sides of the plate.)

There are some sporting ventures where being able to use both hands serves a truly useful function. Combat sports come to mind, with the ability to deliver a surprise punch in the face having a useful role (indeed, the element of surprise introduced by a strong left in hand-to-hand fights is considered one potential reason why lefties did not become extinct). Tennis, where the skill of smashing a waffle iron against a ball with both the forehand and backhand whilst sprinting to different sides of the court, offers clear gain for those who can develop the skill.

But baseball? Really?

After all, 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.”

Alternately, it may be that there are different evolutionary impulses at work within the contrived setting to which Breslow referred. Specifically, players may reach a point where they show a lack of aptitude with their natural hand, and so they try to spin around.

Natural selection—and the incentive to win playing time by overcoming a shortcoming— may be in play.

“I didn’t like sliders from right-handers on my right side,” Chili Davis, now the A’s hitting instructor and one of the best switch-hitters of the ’80s and ’90s, once suggested of his decision to try switch-hitting in his first year of pro ball. “Anything that spun, from a righty to me hitting righty, I was running to the dugout. And I knew I could [switch-hit].

“But in order to teach yourself to hit on your opposite side, you should be ready to hit on one side,” Davis—a natural right-handed hitter who suggests he ultimately felt more natural hitting from the left side—added. “If you can’t hit on one side, there ain’t no stinking way in this world that you’re going to be able to switch-hit.”

The desire not to have to chase breaking balls away and the opportunity to take advantage of speed by hitting from the left side both factor prominently in the decision to switch-hit. Still, the why doesn’t really illuminate the matter of efficacy.

Perhaps it makes sense to introduce players to switch-hitting only when they’ve proven they cannot succeed just while hitting from one side. Rays manager Joe Maddon favors an alternate approach.

“Hitting from both sides, if you started with a kid who was young enough, you could get it done in a pretty efficient way,” said Maddon. “But all Little League should have kids be required to hit from both sides—not throw from both sides. Then you find out who has that aptitude for it, and if he does, let him do it, and if he doesn’t, keep him on that one side. Truly, down the road, if he’s efficient, it’s so valuable.”

Yet there’s an element of the unknowable. Does anyone doubt that Mickey Mantle’s career would have been just as great had he simply stuck to one side of the plate? Are there not many players who struggle so desperately from one side that they would have been better off never having been introduced to switch-hitting?

Barring some horrifying experiment in eugenics and cloning (and at the risk of sounding callous, it seems that a study of the efficacy of switch-hitting is a poor reason to tinker with the very fabric of humanity), there’s no way of performing a study to determine, truly, the efficiency of cultivating the skill of switch-hitting versus having players remain committed to their natural side. In Maddon’s experimental universe, there is no control against which to test the value of the idea.

(As an aside—Is Maddon not the easiest manager in big league history for whom it is effortless to conjure an experimental universe? Would anyone be surprised to discover a subterranean particle accelerator at Tropicana Field, with a door guarded by Albert Camus and Alan Greenspan?)

And so, when it comes to switch-hitting, there is only curiosity and guesswork.

Or, at times, there is neither.

Max Speier offers an enthusiastic flail of Lightning McQueen and misses his intended target. As he retrieves the ball that ended up in the bushes behind him, he pronounces, “I was very close! Baseball is fun.”

Good enough.

Thank you for reading

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The very end put a big smile on my face. I really enjoyed reading this, a humorous and light-hearted break from "gory mathematical details".
The baseball coach at my high school was Ben Lefebvre, father of Jim Lefebvre, and credited with inventing the batting tee for learning to hit.
One year he taught the entire team to switch hit. By the end of the season his team had the highest batting average in their league.
At lower levels, switch hitting is easily learned (with a good teacher).
I've read that if there is a dominant eye, that is what is important. It has to face the pitcher. After all, you have to both see the ball and control the bat to hit the ball.
That subterranean particle accelerator at the Trop was probably installed so that Josh Kalk could keep up with his former life as a high-energy physicist. Josh...if you're listening: How about we do an experiment together, along with Ike Hall, John Walsh, Jeremy Williams, ... (am I missing anyone?).
"...54 percent were classified as right-handed, 33 percent as lefties, and a whopping 13 percent were switch-hitters."

I find that the most fascinating factoid concerns those 33% who bat lefty, compared to 10% of the population being southpaws.

I am not convinced that the advantage is that great that that so many more lefties are better hitters than righties, in order to account for such an anomaly in the numbers.

Rather, I wonder how many righties went against their nature to become lefties, and then made a conscious decision never to go back?

Any ideas how this can be investigated?