Why Endurance Matters: The Human Brain is Getting Smaller

     About three years ago, when I finished writing a book on the adventure of running America's largest ultramarathon, I titled the manuscript Running Wild.  Before going to press, the publisher changed the title to The Longest Race: a Lifelong Runner, an Iconic Ultramarathon, and the Case for Human Endurance.  I thought it sounded awfully textbooky, but in the publishing biz the title is usually the publisher's call.  Later, I wished I'd held out for Running Wild.
     The thing is, for 99 percent of our evolution as bipedal hunter-gatherers, we humans were wild.  For all those hundreds of thousands of years, our ancestors had to have enormous endurance and savvy just to survive.  A Paleolithic human was to a modern human what a wildcat is to a house cat, or a wolf to a dog, or an aurochs to a cow.  Now, we've been thoroughly domesticated.  We're cowed!
     The domestication of humans began with the advent of civilization, and with our growing dependence on technology to do what we'd previously depended almost entirely on our bodies and brains to do.  Today, we reflexively associate tech advancement with becoming smarter, and assume that while we may be physically weaker than our nomadic ancestors were, we're mentally far stronger.  But anthropological research says that may not be true.  Here's an excerpt from my forthcoming book, tentatively titled Racing to the End of the World:

   Between the beginning of civilization and today, it seems, the overall size of the human brain has apparently diminished by 15 to 20 percent.  In the last 500 years (the most recent 0.01 percent of our evolution), and especially in the past 50 years (the most recent 0.001 percent), equipped with our computers, Internet, and rockets, we have conquered the earth and are eyeing other planets—and meanwhile have lost a substantial part of the organ that enabled us to achieve that conquest.  Now, the conquerors are being conquered.  The size of the human brain peaked at about 1,500 cubic centimeters during the time of Early Modern Humans, or so-called Cro Magnon man, 20,000 to 40,000 years ago.  Now look what’s happened:

 

                              Cro Magnon Brain

(after 99.6 percent of our evolution:   1,500 cc

 

Modern Human Brain

(after just the subsequent 0.4 percent:  1,300 cc

 

  The most convincing confirmation of this came in 2010, when anthropologist Antoine Balzeau of the French Museum of Natural History examined the skull of a 28,000-year-old Cro Magnon skeleton that had been found in a cave in Dordogne, France.  Using advanced imaging technology, Balzeau made an endocast showing that the brain this skull once contained had been 15 to 20 percent larger than the modern human brain.  Other studies, cited by University of Wisconsin anthropologist John Hawks, indicate that the shrinkage since Cro-Magnon man has been about 10 percent, or 150 cubic centimeters—an amount of brain about the size of a Macintosh apple—the original kind, with a lower-case “a”.

   When I was a kid first learning about evolution, I heard science-fiction-inspired jokes about humans eventually becoming giant heads with tiny vestigial appendages.  But now, instead, the brain getting smaller?  Doesn’t that totally contradict what we know of human progress? And how could I not have heard of this?  It’s not that the evidence of a significant shrink is much questioned.  And I’m not a conspiracy theorist, but I can only infer that for some reason this shrinking of our brains is a thing that the media most of us depend on for news or stimulation have very little incentive to cover.  The U.S. economy—and increasingly the world’s—is heavily invested in consumer technology sales.   It is only lightly invested in serious education, environmental protection, human health, adaptation to the far-reaching ravages of global warming, preparation for the coming destruction of coastal cities, replacement of deteriorating roads, bridges, pipelines, water mains, and other costly infrastructure, and a long list of other urgent needs of the kind it will take hard use of our brains to meet.

      Consumer technology (including all the devices used to deliver passive entertainment, chatter, and distraction) generates the lion’s share of revenue that, through advertising and promotion, pays for and controls the major news media.  Just watch how much of the advertising is for cars, fast food, and drugs, along with a fair amount of “hey, we’re good guys” PR to appease those of us who have gotten too suspicious--like the BP ads in the wake of the Gulf oil rig disaster assuring us that BP is invested in America and is our friend.  As the Romans found, before their collapse, there are benefits to be gained by keeping the populace satisfied with “bread and circus.”  Their formulation was later updated by Marie Antoinette’s “Let them eat cake,” before her brain-severing demise, and more recently by the hugely profitable but debilitating American penchant for quelling anxiety with Twinkies, doughnuts, and fries.  There’s no political or commercial profit in pointing out that people may be getting dumber.

                  

Bodies Before Brains: How We Got So Smart

Running with my 2-year-old grandson, Josh, has been a great revelation.  It has confirmed, for me, how we humans, out of all the millions of species on this planet, came to be the world-dominating animals we are.  And what it has confirmed is the very opposite of what most of us were taught in school—the idea that humans became what we are because of our big brains.

I’ve had a personal tutorial, these last few months, on how our development as the amazing creatures we are began with our bodies. Not that we didn’t have brains—so did apes, whales, and elephants.  But it’s what our unique physical challenges compelled us to do, in order to survive over hundreds of thousands of years before civilization began, that made the brain develop as it did.

 

            [Note to myself: write the next post, after this, on why the human brain is now shrinking, at an alarming rate in evolutionary time: the data, the documentation, etc.]

 

            I knew this, about the body developing first, long before Josh was born.  I became familiar with the work of the evolutionary biologists David Carrier and Dennis Bramble at the University of Utah, and Daniel Lieberman at Harvard, a quarter-century ago when they published their path-breaking article “How Running Made Us Human”—a cover story in the journal Nature.  The gist of their explanation was that prehistoric humans, lacking the physical power, speed, and built-in weapons (claws, sharp teeth, horns) of other big animals, eventually learned to survive by developing endurance rather than speed, to become successful “persistence hunters.” 

Years later, I elaborated on this revolutionary understanding of our origins in my book The Longest Race: A Lifelong Runner, an Iconic Ultramarathon, and the Case for Human Endurance.  But now, knowing this has become personal in a whole new way, because suddenly I’m seeing that the development of an individual person in some striking ways parallels what we now know was the development of our whole species.

I got a first inkling of this when my daughter, Elizabeth would bring Josh into our living room, when he was still in his first year, and he’d start running back-and-forth between the easy chair and the couch—wow, ten feet without a fall!  Soon, he’d run the ten feet and hurl himself onto the couch like a twelve-year-old doing a belly flop into a pool, laughing with glee.  Then, after a few weeks, he was running laps around the living room.  One day he ran 50 laps nonstop before I stopped counting, smiling and clapping and having the time of his life.

            I should clarify that Josh is in no way slow in his development of language.  He loves to talk, and surprises us every day (he’s now 2) with the new words and phrases he’s learned.  But all the joy and delight that we (and he) experience as he develops his linguistic and mental faculties were clearly preceded by the joy and delight of learning to stand up, walk, run, do flying belly flops onto couches, and then go for long runs with “Gampa” (that’s me) on the trails and roads in our neck of the woods.  Significantly Josh did a lot of running before he learned the word “run.”

            It’s also significant that Josh’s running is very different from that of an adult who has taken up running for the first time at age 30 or 40.  It’s not so mechanical or purposeful.  I don’t think he starts out with the thought “Let’s run a mile.”  For one thing, I’m sure he has no idea what a “mile” is.  His running experience is far more varied, complex, and non-goal-oriented than that.  He obviously feels the action in a way a lot of adults don’t quite: for him it’s as much like the pleasure of dancing to the sound of a great song as it is a matter of going somewhere.  He’ll run with little skips, or leaps, sometimes waving his arms over his head like a World Cup player who’s just kicked a goal.  Or he’ll suddenly speed up and yell “Go fast!” but with no suggestion that he’s racing, just that this is fun!

            But here’s the really interesting thing: as he runs, he’s also watching, observing, with an acuity that often amazes me.  One bright clear day, around mid-morning he stopped, pointed at the sky, and said “moon!”  I glanced up, laughed, and said “No, Josh, the moon comes at night, when it’s dark.”  But he insisted, “moon!”  I looked up again, narrowed my eyes, and then yes, there it was—a tiny, faint white sliver in the blue-white sky.  I have good vision (still don’t wear glasses), but found myself wondering, how did he see that?

Now, if he sees the moon, I know better than to question him.  He’ll do the same thing with all kinds of other observations, too.  “Plane! Up dere!”  Or “spider web, get a stick!” (The first time we found a spider web on an outdoor chair, I had shown him how to brush it off with a stick.)  I’d look where he was pointing, look really hard, and then—sure enough—a few feet off the trail in a tangle of brush was a barely visible web.  How did he see that? 

And then it hit me: Josh was instinctively doing what humans before civilization had to do to survive: He was watching, observing, using his eyes and ears with an acuity we modern grownups have largely abandoned. The “persistence hunting” theory wasn’t just about humans learning to outrun antelope or horses over long distances, but about all the tracking and observing they had to do before and during the chase, which might take hours.

It struck me that maybe one of the reasons a lot of modern endurance athletes have moved from the roads to the trails is that trail-running (or hiking, or mountain biking or climbing) both requires and invites more active engagement with the environment—watching the ground for rocks and roots, or pitfalls or cliffs, or adapting to the sun or wind or ice as we go, and getting closer to the miracle of the living world we evolved in,

            If you’re still learning (as we all are, but especially if you’re only 2 years old), your perceptions are exceeded only by your curiosity.  As we run, Josh will often stop to examine something: an exotic beetle I would not have noticed, or an ant lugging a twig five times the size of its body, or a crack in the pavement, or a lizard.  And he’ll turn to me and say “What dat?”  Or he’ll cock his head, gaze in a particular direction, and ask “What dat sound?”  Sometime it will take a few seconds to know what he’s hearing, because I have subconsciously screened it out.  A few days ago, nearing the end of summer, he said “What dat sound?” and it took me a minute to realize: Crickets!  Had I gone the whole summer without consciously hearing (and appreciating) them?

            There are 70 years of life experience separating Josh and me, but running with Josh is teaching me, as nothing else ever has, some important things about how we developed both as individuals and as a species.  That development began (and begins) with our physical experience—what we see and hear on the trail, or what we feel as we trip on a rock and lose balance.  Without that formative experience, there’d be no later on. There’d be no big-brain competence.

Commentators might talk about the virtues of a politician who seeks “balance” in his policies, between forceful action and prudent caution.  But understanding the meaning of balance had to begin with learning not to fall on your face!  Today we extol the concepts of “standing up to terrorists,” “walking the walk,” “running for office,” “tripping up an adversary,” “stumbling in a new business adventure.” We speak of the “pursuit of happiness,” and a “nation that shall endure,” and on and on.  Those are metaphors now, but they began with literal, physical, experience. 

            It’s intriguing to me that although I’m one of the most experienced endurance runners on the planet, I can learn so much and so profoundly from a little guy who’s just starting out—but who clearly delights in what he’s learning.  Josh is reminding me of what it is to be young and fully alive.  He makes my heart leap.

            I’m suddenly reminded of a poem William Wordsworth wrote a couple of centuries ago, which I last read when I was in college, and just now looked up again:

 

                        My heart leaps up when I behold

                        A rainbow in the sky:

                        So was it when my life began;

                        So is it now I am a man . . .

                        The child is father of the Man . . . .

 

What on Earth could that mean?  The past learns from the future?  If that is so, it suggests that we can only survive by having enough imagination and acuity to envision the future—to be alert enough to see what lies ahead on the trail of life.

 

           

No Longer the 'Loneliness of the Long-Distance Runner'

Remember the famous story (and later the movie) of that title—Loneliness of the Long-Distance Runner?  As a kid, I was always able to relate to it.  I was introverted and drawn to solitary pursuits, such as going off into the woods by myself to look for turtles or salamanders.  As an adult, I’d always run alone—alone on wooded residential streets on a winter’s night, passing the warm lights of windows in which I caught glimpses of families eating dinner or watching TV; alone on forest trails hearing only the wind in the trees; alone on a highway shoulder braving the roar of long-haul trucks passing—but rarely with another runner.

            In recent years, distance running has become a much more social activity, and I have the impression that there are now millions of people who have never run alone—and who also have a very amicable life with training partners, club members, and Sunday long-run groups.  But after high-school and college cross country, I never really got into that.  The day I graduated from college, after seven years of running with teams, I remember standing in the amphitheater where our commencement ceremony was about to begin and feeling a sudden, nostalgic sadness that there’d be no cross-country for me that fall, and my running days must be over.

            Running for adults, as we know it now, was still so rare that on that day that I didn’t even know it existed.  I’d heard of the Boston Marathon, but thought of that as an event for Olympians.  Other than that, I assumed running was for people between the ages of 15 and 21.  So, if you had asked me in those days what the average age of a serious runner was, I’d probably have said around 18. 

Today, it would be a different story.  If you said “suppose you see two people running along a bike path or trail together, and they’re an “average” pair, and you add their ages, what would the total be,” my answer now would probably be around 74.  A typical pair might include a 36-year old and a 38-year-oold, or a 34 and a 40, or a 28 and a 46—all very common ages in today’s running population. In fact, there may be more 37s than 18s now, judging by how many kids no longer even go outdoors when there’s an Xbox or ipod to play with instead.

            If 74 would be a reasonable composite age for a pair of typical running companions today, then I guess my new situation is right in step.  I’m 72, and my new running companion—my grandson, Josh—is 2.  Together, we’re 74.

            Josh doesn’t yet know that he’s “only” two, or that running a long distance is in any way unusual.  For me, though, this new partnership has been a huge revelation.  As long as I can recall, I’ve heard of kids that age being called “toddlers,” and have just assumed that when they go anywhere under their own power, they “toddle.”  Not so!

            Josh did indeed toddle for a few weeks when he was one, but even his toddle was a primordial run; he’d wobble across the living room slightly out of control and throw himself into the couch.  Soon, he was running all the way around the perimeter of the room, then tackling the couch like a linebacker.  And before long, running laps around the living room—smiling, laughing, waving his arms in the air like a striker who’s just scored a goal.  His favorite activity was going outside for a walk, and .he didn’t discriminate between a “walk” and a “run”—when he wanted to go outside, he’d just plead “go walk?”  And then, as soon as we got out to the road (a rural road where cars are rarely seen) he’d break into an exuberant run.  His legs were very short (he was only about two-feet six), but the tempo was almost the same as an adult’s—about 180 strides per minute.  He flew!

            Now, at age 2 ½ , Josh still has no knowledge that his grandfather is a runner, or indeed that there’s even any such a category of person as a runner, any more than there’s such a category of person as a “breather.”  By now, he and I have several times run a good distance together, but never with any particular encouragement from me.  If Josh wants to stop suddenly and play in the dirt for a few minutes pretending his hand is a bulldozer (he learned to say “bulldozer” before he learned “run”), that’s cool with me.  I intend never to be a Little League grandfather.  Josh might have the genes to be a good distance runner, but whether he pursues that or not will be entirely up to him.  I’ll be just as happy if he decides to play soccer or violin.

            What I love is that I now have a wonderful running companion, and every time we head out the door it’s an adventure.

A Running Streak for the Ages

Long-distance runners are a dogged breed, probably tracing to our genetic heritage as persistence hunters.  For some, that doggedness is manifested by the gritty way we run races (e.g., pushing through the glycogen-deprivation “wall” of a marathon, or late-hour delirium of an ultra), and for others it’s manifested by the obsessive way we get out for a run every day no matter what.

Among the latter, there’s that small population of runners who call themselves “streakers,” not because they run naked in public (though, who knows, maybe some have done that too), but because they have run every day undaunted by illness, injury, hail, or or anything else, and have counted how many consecutive days they’ve done this so far.  There’s even an organization, the United States Running Streak Association, Inc., which lists the names of runners who have exceptionally long streaks.

The official definition of a running streak, as adopted by the USRSA, is “to run at least one consecutive mile within each calendar day under one’s own power….”  And to be officially listed as a streaker on the USRSA Web site, you have to have kept your streak going for at least a year.  Some people have done it for 10, 20, or even 30 years, which makes my head hurt to even imagine.  Last summer, I read with fascination about a guy who happens to live in the next town from me, Mark Covert, who had just ended his streak at a record 45 years.

What motivates a streaker?  The Web site of USRSA recently published an article by Herb Fred, who had run about 120,000 miles until one day in 1987 he collided with a car that had run a red light, and smashed its windshield with his head.  When he was released from the hospital 11 days later, he decided to resume his running on a treadmill, where neither rain nor hail nor errant automobiles could stop him.  Since then, as of January, 2014, Fred—now 84 years old—had never missed a day. 

I could never do what Fred has done—nor would I even dream of trying.  Fred notes that in his outdoor days, there was more risk of injuries, and that he’d had “just about all of them, from blisters to tendonitis to muscle tears to bloody urine, as well as numerous basal cell and squamous cell carcinomas of the skin.” And, he wrote, “I’ve also suffered from penile frostbite that resulted from a long run against a strong wind in sub-breezing temperature.”

I will consider myself very fortunate if I can still be running (or even alive!) at Herb Fred’s current age (I’m still a youthful 72), but there’s no way I’d give up the pleasures of mountain trails, fresh breezes off the Pacific, or a warm September sun on my bare skin, in order to achieve that.  And as far as streaks go, by the USRSA definition, I could never be listed at all, since I’m sure I have never gone a year without a few days off—whether due to injury, family emergency, travel (although I have done a few runs back and forth through airports, as an alternative to vegetating on a plastic chair), or just plain fatigue. 

I have, however, achieved another sort of streak—instead of running one or more miles every day, competing in one or more long-distance races every year.  In November, 2012, I completed the JFK 50 Mile (America’s largest ultra), bringing my streak of consecutive years of racing to 56.  After a few days off, I began training for #57, but as fate would have it, several circumstances prevented me from entering another race in 2013.  I suppose I could have limped through a 5K, but my streak was never an objective.

And so, after a year of personal travail, perhaps a new streak will now begin.  I’m slower now, but still hoping to run another ultra in the coming year.  The legs and lungs aren’t what they used to be, but the mountains and ocean breezes are still calling—as they have been since my prehistoric ancestors (and yours) began running a thousand centuries ago.  As individuals, we come and go.  But the way our species has continued to run, across the millennia—whether to hunt, carry messages, run races, beat Mark Covert’s record, or just feel the exhilaration of quick feet on a mountain trail—has been truly a streak for the ages.