When you watch a pitcher wind up and throw a fastball down the middle, or a quarterback step out of the pocket and make a successful long pass, you’re seeing millions of years of human evolution and adaptations in action.

Or so say researchers Daniel Lieberman and Neil Roach. Their study, published today in Nature, determines that this uniquely human trait—high speed and high accuracy throwing—originated with our ancestors Homo erectus, two million years ago.

Darwin speculated that by freeing up the arms, bipedalism may have enabled our hominin ancestors to hunt effectively using projectiles. But scientists had been unable to pinpoint the exact time throwing became viable.

“When we started this research,” Roach says, “we asked: How do we do it? What is it about our body that enables this behavior, and can we identify those changes in the fossil record?”

The researchers began by creating a complex model that incorporated current research about the biomechanics of throwing. Using that model, they were able to explore how morphological changes to the body—wider shoulders, arms that are higher or lower on the body, the ability to twist the upper body independently of the hips and legs, and the anatomy of the humerus—affect throwing performance.

They also studied 20 experienced human throwers during overhand baseball pitching, demonstrating that several derived anatomical features that enable elastic energy storage and release at the shoulder are central to our ability to throw powerfully and accurately. (Video is available of these mechanics on Harvard’s website.)

“We try to push these bits of anatomy back in time, if you will, to see how that affects performance,” Roach says. “The important thing about our experiments is that they went beyond just being able to measure how the restriction affects someone’s ability to throw fast and accurately—they allowed us to figure out the underlying physics. For example, when a thrower’s velocity dropped by 10 percent, we could trace that change back to where it occurred.

“In order to test our evolutionary hypotheses, we needed to link the changes we’d seen in the fossil record to performance in terms of throwing,” he continues. “This type of analysis allowed us to do that.”

This throwing ability was incredibly important for our ancestors, the researchers say. It helped them become more successful hunters and carnivores, paving the way for a host of later adaptations, including increases in brain size and migration out of Africa.

However, while speed and accuracy proved a crucial development for early hunters, the study’s authors warn that repeated use of this motion can result in serious injuries in modern throwers, especially in young baseball players, who often suffer from laxity and tearing in the ligaments and tendons of their shoulders.

“I think it’s really a case of what we evolved to do being superseded by what we’re now asking athletes to do,” Roach says. “Athletes are overusing this capability that gave early humans an evolutionary advantage, and they’re overusing it to the point that injuries are common.”

Image: Rick Dikeman/Wikipedia

San Francisco Giants closing pitcher Sergio Romo’s fastball can reach speeds of up to 90 miles per hour. How can any hitter see a ball at that speed accurately enough to hit it?

Well, actually, according to University of California researchers, they can’t. (No wonder Romo recorded over 60 strikeouts last season.)

It takes about one-tenth of a second for the human brain to process what the eye sees. At that rate, a 90 mile per hour fastball would whiz past a slugger, and a tennis ball moving at 120 miles per hour would advance 15 feet before the brain registered the ball’s location.

Publishing last week in the journal Neuron, Gerrit Maus and his colleagues determined that the brain “pushes” forward moving objects so we perceive them as further along in their trajectory than the eye can see.

Using functional Magnetic Resonance Imaging (fMRI) the team located the part of the visual cortex that makes calculations to compensate for our sluggish visual processing abilities. They saw this prediction mechanism in action, and their findings suggest that the middle temporal region of the visual cortex known as V5 is computing where moving objects are most likely to end up.

For the experiment, six volunteers had their brains scanned as they viewed the “flash-drag effect” in different videos. “The brain interprets the flashes as part of the moving background, and therefore engages its prediction mechanism to compensate for processing delays,” Maus says. (You can try this yourself with the UC Berkeley scientists’ flash-drag videos available here, here, and here.)

“The image that hits the eye and then is processed by the brain is not in sync with the real world, but the brain is clever enough to compensate for that,” Maus says. “What we perceive doesn’t necessarily have that much to do with the real world, but it is what we need to know to interact with the real world.”

Too bad the Berkeley scientists can’t somehow improve (or compensate for) umpires’ vision.

Image: artolog/Flickr

…Washington suggested that the Series could go in either direction—pitching or offense.

Hmmm. I’m a big fan of Wash, but that comment is a little Yogi Berra-like. Good news for all of us that Charles Pavitt, of the University of Delaware, has the actual numbers. He crunched hitting, pitching, fielding and base-stealing records for every MLB team over a 48-year period from 1951-1998.

Pavitt found hitting accounts for more than 45% of teams’ winning records, fielding for 25%, and pitching for just 25%. Furthermore, the impact of stolen bases is greatly overestimated. (Take that, Rickey Henderson!) Pavitt’s findings are published this month in the Journal of Quantitative Analysis in Sports.

Want more baseball research? Last year, around this time, we wrote about a study published in PLoS ONE on the “breaking ball.” The authors behind the study say that curveballs can’t break nor can fastballs rise—it’s all an optical illusion. ScienceNOW has a great description of the experiment that led the scientists to their findings.

NPR produced a story last week about pitches hitting batters. Apparently, the higher the temperature in the ballpark, the more batters get hit, according to Richard Larrick of Duke University.

Was it because they would sweat more, and the ball might get slippery and hard to control? Or was it something intentional?

Larrick had a hunch it was the latter. He knew from previous research that if you put folks in a hotter room, the more aggressively they’ll act toward one another. He theorizes that the act of a pitcher intentionally hitting a batter could have a similar cause. But at this point, it’s only a theory (published in the journal Psychological Science).

Researchers (and baseball fans) Alan Nathan and Lloyd Smith wanted to confirm or dispel some of the rumors about the game so they developed a “Bat Lab” at Smith’s Washington State University. According to Popular Mechanics, their machine can test pitch velocity and bat speed—

to calculate what they call the coefficient of restitution (COR). “[It’s] the bounciness of the ball off the bat,” Nathan says, and it’s the primary metric the team uses for testing bats—and busting baseball myths.

In the lab, they’ve discovered that baseballs are no different now than 40 years ago and that a humidor actually works well for keeping baseballs in the park at Denver’s high elevation Coors Field. In addition, they discovered that while corked bats may hit the ball more often, they do so with less power. Their research was published earlier this year in the American Journal of Physics.

Speaking of bats, USDA Forest Products partnered with MLB a few years ago to try and reduce the number of broken bats in the game. Engineer (and baseball fan, one would hope) David Kretschmann watched video of every shattered bat, recording the who, when, and how of every breakage. He then tested and analyzed hundreds of bats in his own lab. He found that the splintering was caused by “slope of grain” issues. On Wisconsin explains:

A baseball bat (or any piece of lumber) is strongest when cut with its length parallel to the grain of the wood. If the slope of grain differs from the center line of the bat by as little as 3 degrees, that bat will be 20 percent more likely to shatter.

Thanks to his research and a new manufacturing trick—the number of broken bats has decreased by half since 2008.

Want a bit more baseball physics? In his Wired blog, Rhett Allain demonstrates the physics of a remarkable fielding play by Rick Ankiel. He estimates the ball was thrown 331 feet from right field to third base at the amazing speed of 111 miles per hour! Read the blog to find out how he made that estimation.

And then just sit back, relax, and enjoy the science of the World Series.

Image of Michael Young: Keith Allison/Wikipedia

Published Wednesday in the Proceedings of the Royal Society, an interesting finding—turns out that pigeons like to gamble. The pigeons in the study were given two choices—they could peck at a key that always would give them three food pellets or at a key that would give them ten food pellets 20% of the time and zero the rest of the time.  All pigeons chose the gambling key over the reliable three-pellet key every time.

An article in LiveScience reported that:

The reason could be that pigeons are motivated by a surprising change from their expectations, according to study author Thomas Zentall, a psychologist at the University of Kentucky. The same phenomenon could explain why human gamblers ignore their losses and focus on their rarer, but more surprising, wins.

Similar behaviors have been found in monkeys.

And just in time for the Giant’s play-offs, PLoS ONE published research on the “breaking ball” this week. The authors behind the study say that curveballs can’t break nor can fastballs rise—it’s all an optical illusion. ScienceNow has a great description of the experiment that led the scientists to their findings. Given the pitchers’ duel between Lincecum and Halladay for tomorrow’s opening game, it should be required reading for Giants and Phillies hitters.

Also in baseball science news this week, new UC Berkeley research on birth order and baseball success. It turns out that younger siblings make better ball players. The research will be published next month in Personality and Social Psychology Review.

More Gulf of Mexico oil spill news this week. Nature had an article about how reduced funding means fewer vessels in the gulf to research the effects of the spill. And in Discover, could the oil be killing thousands of fish where the Mississippi meets the gulf in Louisiana? When the image was first published, the oil was the cause, then the blame switched to agriculture run-off. Now it may be the oil after all.  More definitive testing will be done.

Finally, does Gliese 581g even exist? Two weeks ago, it was the exoplanet named most potentially habitable, but this week, Swiss scientists could neither confirm nor deny the existence of the planet. Francesco Pepe of the Swiss Team told New Scientist, “We easily recover the four previously announced planets, ‘b’, ‘c’, ‘d’, and ‘e’. However, we do not see any evidence for a fifth planet in an orbit of 37 days.” But he told Science via email that “we can’t prove there is no fifth planet.” Hmmm…

What science news did you find controversial this week? Share with us!

Creative Commons image by Minesweeper