Discover: Running's hand in evolution

Last year, PBS presented a fascinating series on The Human Spark.

In this short clip, narrator Alan Alda and Harvard scientist Dan Lieberman explore why our ability to run (specifically, long distances) may have been the catalyst for the evolution of our bigger brains.

Running clinched our predominance as swift and crafty hunters. And it also secured our dominance over large game, which, in turn, supplied our hungry ancestors with a steady stream of brain-boosting protein.

I find all of this fascinating, as it combines two pastimes I love: running, and ruminating over the many ways and whys re: the functioning of the human brain. Lucky for me (and you, if you're into these things, too), Dr. Lieberman has written more on these matters in a just-published book, The Evolution of the Human Head.

In educational interest, article(s) may be quoted from extensively.

From the Jan/Feb 2011 issue of Harvard Magazine (while the entire article is found online, if you'd really like to get a feel for the concepts, please see the article's PDF version):

BENEATH SHELVES OF BOOKS on the biology of bone, a collection of skulls and running shoes lies in a jumble on a countertop. The skulls come in a range of sizes and shapes, from the tiny and sharp-toothed, with large orbits for the eyes, to the hefty and humanoid. The shoes are likewise varied, from brightly colored Nikes, to fluorescent ASICS, to slipper-like Vibram FiveFingers™ with separated toes—like a glove—intended to mimic barefoot running. These collections neatly bracket the research interests of Daniel Lie-berman, human evolutionary biologist: a head-to-toe interest in the human body, its morphology (the science of an organism’s form, including the study of specific structural features), its development, and its evolution.

“I do seem to end up working on the two ends of the body, and not so much in between,” he muses. “I never thought that would happen in my career. It’s bizarre.”

But the apparent dichotomy is bizarre only in the abstract, because Lieberman’s interest in feet—and human endurance running—began with his interest in heads. The two subjects are deeply linked. The theory that humans evolved to become endurance runners so talented that a team of barefoot hunters on a hot African savanna could actually run a large antelope to ground is based in part on skeletal evidence from the head—a subject about which Lieberman has just published a weighty book, 15 years in the making. ...

Lieberman’s interest in running began with his research on the head in conjunction with Dennis Bramble from the University of Utah. Alone among apes, humans have a special ligament at the nape of the neck, attached at the back of the skull, that apparently helps the head to remain stable during running. Humans also have external noses combined with short inner nasal cavities that create turbulence in several ways during breathing, adaptations that may increase the ability to humidify incoming air, or dehumidify exhaled air, in arid climates. “We can also see in the fossil record when human heads develop larger organs of balance [the semicircular canals] that are better able to sense the rapid pitching motions caused by running,” Lieberman says. This was about two million years ago, when humans began eating meat. These changes in the ears, neck, and nose, along with more balanced heads, may all be features that allowed early human endurance hunters to chase prey until it collapsed from heat stroke. ...

Energetic abilities, such as endurance running, are another distinctive human feature: “There are very few animals that will willingly run five to 10 miles, let alone a marathon,” he says. Most humans are good at endurance, but pathetic at speed: “My dog is faster than I am—but my dog could never run a marathon.”

Interested in seeing some of the science behind the theory?

Check out Brains, Brawn, and the Evolution of Human Endurance Running Capabilities [pdf].

Lieberman's research has changed more than minds, it's changed the doctor's running habit, too. Now a proponent of barefoot running, the professor introduces us to this ever trendy-but-traditional style:



In Harvard's Skeletal Biology Lab, Lieberman and colleagues are continuing to amass evidence-based data to support the barefoot running style, focusing on "studying the biomechanics of different foot strikes in endurance running and the applications to human endurance running prior to the modern running shoe."

Last year, a hotly anticipated study on barefoot running was released by the Harvard team; see RunBare's in-depth review for more.