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Wednesday, April 27, 2016

Why You Move the Way You Do

Written by Simon Worrall

Animals—including humans—evolved to get from place to place.

“Everybody got to move somewhere,” sings Bob Dylan in "Mississippi." But why? Are we constantly in motion due to some fatal flaw in our make-up? A neurotic aversion to standing still? No, says Matt Wilkinson, author of Restless Creatures: The Story of Life in Ten Movements, the reason is bigger than that: Movement is what makes us human and has been the driving force of life on Earth.

Talking from his home in England, the Cambridge evolutionary biologist recalls what pterodactyls taught him about movement, how getting lost is important, and why our feet are, in his words, squidgy.

You say that locomotion has been the driving force of evolution. Explain why.

From the very beginning, right back to the very origin of life, those organisms with the ability to explore their environment had access to resources that others didn’t. Not only that, they were also able to move from place to place. Should any mishap befall them, they were more likely to survive. Locomotion has dominated the evolution of life and continues to do so. I ought to qualify that because plenty of creatures have become static and stay in on place. But you always find that somewhere in their life cycle, there is some motile phase. The benefits of being able to move are just too great.

Darwin is the inventor of the theory of evolution. He doesn’t say much about locomotion, though, does he?

Darwin’s approach was to put together a mechanism by which evolution might work from generation to generation. My approach is slightly different as I’m looking at a broader canvas. I’m not challenging the Darwinian idea, but rather embracing the idea of how important locomotion is. When you look at life as the history of locomotion, everything comes into focus.

As a child, you were fascinated by pterodactyls. Wind back the clock and explain how this childhood obsession got you interested in movement.

I guess all children are interested in dinosaurs but the extinct flying reptiles really captured my imagination. Here we have a group that is completely extinct but managed to do something very few groups have: develop full power of flight. It gave me a great opportunity to try and understand how these things worked. I became very interested in evolution in general, and in the rules of biomechanics: how living things work as machines, how they move, how they operate. It opened my eyes to how dominant this idea of locomotion is: how fully and thoroughly animals are shaped by the need to move effectively from place to place.

The received theory is that homo sapiens got his upright gait in the transition to a savannah environment, where it paid to stand tall. We got it wrong, though, didn’t we?

[Laughs] I think so. Though the idea isn’t mine alone. I agree with experts in this field, who suggest that the real transition to being an upright biped happened in the trees. The savannah stage was when we refined it. We never really became specialized in suspending from branches overhead like the apes. It meant our anatomy, our bodies, were still capable of becoming terrestrial bipeds.

To adapt the Nancy Sinatra song, these bones are made for walking, aren’t they? Talk about the everyday miracle of feet.

[Laughs] We take it so much for granted, but our feet are absolutely amazing marvels of bioengineering because they have to adopt different functions throughout every step. When we put one foot down, the foot needs to be quite squidgy, because it needs to provide a nice, stable base for the weight of the arches overhead and also to mold to the ground. When we lift the foot up, we want it to change into a more rigid lever, to give us a nice, efficient push-off. We have this nifty mechanism called the windlass mechanism, after the windlass crank-like system. As the toes get bent back on the ground, the heel gets pulled forward, twisted a little, and then that locks the foot into a rigid configuration. It’s a fantastically Gothic structure that enables us to walk efficiently. By contrast, the apes have emphasized the moldability of the foot much more than we have because they use the foot to grasp in a way that we don’t anymore.

One of the key fossils found in East Africa was that of a 4.4 million-year old-female. What did Ardi tell us about our early history?

Ardipithecus was about 4.5 million years old, putting her close to the divergence point of chimps and humans 6-7 million years ago. The prevailing opinion had been that our last common ancestors were chimp-like and walked on their knuckles. But Ardi didn’t have any knuckle-walking adaptations, especially in the wrist. Ardi also seemed able to walk bipedally much better than a chimp. This threw a spanner in the works as far as the theory of human locomotion was concerned.

Of course, if we didn’t have some kind of guidance system we would just crash about bumping into things. Talk about the GPS system we all have in our brains.

It has been argued that the brain is for locomotion, first and foremost. All the other stuff —the thinking, emotions, and consciousness—is essentially a bonus: a more refined way of gathering inputs and then generating an appropriate output, which in many cases, is just knowing which way to go.

It all goes back to the earlier stages of the animal kingdom. Once we start to get to jellyfish and sea anemones, we begin to see the use of the nervous system to steer the animal around. Sea squirts also give us a very useful illustration of the vertebrates’ closest invertebrate relatives. As larvae, they swim around and have something clearly related to the precursor of our vertebral column and central nervous system. But when they turn into adults and stop moving around, the central nervous system becomes a useless extravagance, so they just digest it.

You hint at an interesting connection between our love of storytelling and the way our brains have been designed for locomotion. Unpack that idea for us.

This is me speculating, but it refers to how our psychology has been adapted for locomotion. Just as our bodies have been clearly adapted for locomotion, so, too, have our minds. One aspect of this is the ability to draw navigational meaning from a sequence of vistas or images. It means we are then able to reconstruct a path from the landmarks that we encounter as we go along. It’s a very useful skill to be able to have because humans were traditionally hunter-gatherer societies so our navigational abilities are extraordinarily good.

Story telling is the same thing. What we’re doing there is taking a series of events that when knitted together into one narrative arc enables us to extract meaning from it. Our ability to draw meaning out of stories could well be using some of the same logical skills we use to draw navigational meaning out of a sequence of images.

You stress the importance to human civilization of what you call “wayfaring.” Explain what you mean.

Wayfaring is exploring locomotion. It’s not just moving as a means of getting from A to B. It’s trying to find out more about your environment through movement. Not just the environment but also about yourself and the world around you. Ultimately, it means getting lost—not needing to know exactly where you are going. Anything that causes you to employ your senses in a more thorough way as you’re moving from place to place is what I mean by wayfaring.

A good example of this is the Batek people of Malaysia, who have been studied quite extensively by Lye Tuck-Po. She found that the exploration of their forest is an immensely important activity for them. It’s not just how they get from place to place. It’s how they discover who they are, and how they find out about their world, connect to their ancestors, and maintain their cultural identity.

The Aboriginal Dreamtime in Australia is another wonderful example. This is a point that Michelle Sugiyama, of the University of Oregon, has made. Some of the stories these people tell are essentially navigational aids. It’s all about the act of exploratory locomotion.

You write at the end of the book that our species is threatened by “our filthy, deadly locomotive technologies.” Explain why you hate the automobile so much—and why a world of “self-generated propulsion” would be a much better place for our children?

There are lots of reasons for my hatred of motorcars [Laughs] Take the vast amount of deaths that they’re responsible for. The World Health Organisation has estimated 1.25 million people are killed in traffic accidents every year. And that doesn’t account for deaths due to pollution or inactivity leading to obesity. It’s also how they impact the psychological side of locomotion by making sure we can’t wayfare. Settlements end up being designed with the motorcar in mind, so more and more of us are living more and more distant from each other. We live and work in very different places. Family and friends are far away. All this makes us isolated.

Cars also break our link with our biological heritage. The idea of connecting to our ancestral past requires us to locomote as we are evolved to do, using our senses and making sure the mind and body are in union. Otherwise, it’s like our minds are passengers in our bodies. Travel time becomes wasted time.

I take it you don’t own a car?

[Laughs] No, I don’t. I’m very lucky living in Cambridge where I don’t have to. At least with a bicycle we are still engaging our muscles. Cycling also offers more options to go off on a tangent, which is what wayfaring locomotion is all about.

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