Reframe Podcast: Episode 5

Exploring the Profound Mysteries of Movement

Bill Berg in classroom

In this episode . . . We explore the mysteries of movement. Since for most of us, movement is such a mundane, everyday activity, it may seem strange to learn that we really don't know all that much about it. But in reality, the ways in which we move actually hide an intricate complexity that is, so far, is actually pretty mind boggling.

Read the transcript

James Loy:

This is Reframe, The podcast from the College of Education, Health and Society on the campus of Miami university. 

In this episode . . . We explore the mysteries of movement. Since for most of us, movement is such a mundane, everyday activity, it may seem strange to learn that we really don’t know all that much about it. But in reality, the ways in which we move actually hide an intricate complexity that is, so far, is actually pretty mind boggling. 

So to learn more we are here Dr. William Berg, professor of Kinesiology. So Dr. Berg, can you start by give us just some quick background on the subject, and maybe explain why it’s so important?

Dr. William Berg:

To me, human movement is actually – other people will disagree – but it is the most important thing we do because it is the only way we have to affect the world. The only way. So memory, perception, cognition, all of that eventually has to serve action. Otherwise it isn’t manifested anywhere. So what I do, what I’ve done in my career, is try to understand how we actually move, and how we learn to do complex and adaptable movements, which is a pretty hard problem. We are not doing a great job on figuring out how that works. It is a hard problem.

James Loy:

And why is that? What makes it such a hard problem to solve? Or, maybe, for someone who looks at this subject very closely, what do you think are some of the biggest challenges facing the field today? 

Dr. William Berg:

For my field, in terms of understanding human movement, the biggest challenges are just understanding the human brain, and how the central nervous system works. We are improving our understanding, but we have a long way to go. So if we could understand what the changes were in the brain when we learn, I think we would have a better idea of what we would need to do to help people learn. But we don’t understand that yet. So I think that is a big challenge.

James Loy:

Do you think . . . is there any way to know how much we don’t know yet? I mean, this kind of makes me think of any number of cosmological problems where as soon as scientists learn the answer to one particular problem, it really just opens the door to so many more questions, so many different things that we didn’t even think to ask in the first place. Is the study of movement like that at all? 

Dr. William Berg:

I can tell you this. In terms of what we know about movement is significantly less than we know about other things. Let me give you an example. So like with cognition – human thought, decision making - we are pretty good at designing, for example, computers that can do the cognition of a human being. There are computers that can beat the chess champions, the chess grand masters. But when it comes to the simple dexterity of picking up a chess piece and moving it to another space on the board, we can’t design a system that can do that very well.

We can design a robot to do that, but that robot then is not adaptable. It can’t decide to move it to a slightly different place. So we are doing a really good at solving the cognition problem, but we are only taking baby steps in understanding how we actually move in a dexterous sort of way. 

So you can . . .  the example by a guy named Daniel Wolpert always suggests is that we have computers that can beat the chess grandmasters, but a five-year-old is far more dexterous and adaptable than any robot that we have created. So relatively speaking, we don’t know very much about this thing we call “action.”

James Loy:

Well, that makes me wonder what makes it such a complicated problem. You know, if you just pulled someone off the street and said, “How do we move?” They would just say, “Well, the brain sends a signal down the central nervous system, or whatever, and tells the arm to “move.”

You know, end of story. You wouldn’t think it would be so complicated. 

Dr. William Berg:

Exactly. You wouldn’t. And that’s because many of the movements we do  . . .  in fact, most of the movements that we do on a daily basis, are unconscious. We just do them unconsciously.

One of the things I study now – I look at how the brain does unconscious sorts of things to help us out posturally. So I study things like anticipatory postural adjustments. 

These are like automatic adjustments your body makes without you knowing it, when it anticipates that something could go wrong. So if I stand up and if I just do this really rapidly . . .

James Loy (Narrating):

At this point in our conversation, Dr. Berg stands to demonstrate one of the specific movements that he studies in great detail. And it is very simple. He just stands straight up, and he has both arms resting at either side, and then he just simply raises both his left and his right arm at the same time until they are extended straight forward.

Dr. William Berg:

. . . of course, these muscles here have to move my arms, but before those muscles will contract, the muscles in my back and in my glutes and my hamstrings contract first. My brain anticipates the consequence of action and plans ahead for it. And it does that all without us having to pay conscious attention to that. And, obviously, it does so very rapidly. So I think . . .  and we don’t understand very well all the predictions that our brain does. So I think that’s one of the reasons it is so complicated. And most of that prediction is done unconsciously.

So it is like the self-driving car. They say we are going to have these things pretty soon. But one of the problems is that we can engineer the human out of the system, and we can engineer at lot of the errors that a human makes out of that system, but what’s the hardest part is the prediction capabilities of the human. That is the hardest thing to manifest in the driverless car – to get the driverless car to predict what’s going to happen. That’s what the human brain is to the equation that is the most challenging part. And we don’t understand that very well.

One thing I’ve heard about with this driverless car is what they need to do is allow the cars to collect information from all the other cars on the road. That will give them, eventually, that prediction capability. But that means they have to be sensitive to all the other things on the road. 

So I think our understanding of how our brains anticipate and predict and estimate what’s going to happen is kind of the cutting edge of understanding human motor behavior. 

James Loy:

So one might think that this would be just akin to a reflex action – but it is not even that, not at all, right? It is all the things that go into even conscious movements, that we are first unconsciously doing. It is all things that the brain did to figure out how to get to that eventual conscious action by using other parts of the body to make that movement even possible in the first place, right?

Dr. William Berg:

Exactly. It is not just the moving of the arm. If it were just that, then we are just robots. And if you look at . . . humanoid robots aren’t very sophisticated. They can walk on two legs. That was only a recent development, and that’s something that toddlers can do – not very well, but they can do it, which shows you how complex just basic locomotion must be. 

Yeah, it is not just the “moving” it is all that has to take place to support that action. And our brain is doing that for us. And most of the time it is doing that for us without our even knowing it.

We didn’t even know we had these things called anticipatory postural adjustments until 1969. Now my students think 1969 was ancient history, but it wasn’t. We didn’t even know we had these things until 40 or 50 years ago. Because the things that we do unconsciously are very difficult to understand. If we don’t know we do them, how do we study them? 

James Loy:

Now assuming that we can study this in greater detail, and continue to learn more. What would that mean? What would unlocking this knowledge make possible? Or what is the potential awaiting us in the future if we suddenly just had these secrets of movement available to us?

Dr. William Berg:

Okay. So, if we could have a better understanding of how human beings move, and especially move adaptably, because that is what robots can’t do. They are not very adaptable. You can get a robot in an auto factory to do the same thing over and over and over again very precisely and very well, but they couldn’t do something different on every try. Like we do.

So I think if we could figure that out it might open up our understanding of how we work, but that might open up new avenues for learning, for rehabilitation that we probably can’t even anticipate at this point.

James Loy:

A little bit earlier you talked about how your current work focuses on studying these anticipatory postural adjustments. So what are some of the things you looked at when regarding these unconscious actions that the brain makes for us, you know, to prepare for the conscious actions that we want to make? 

Dr. William Berg:

So one of the things we spent a number of years trying to understand was how fatigue affected those. And what we found was, and this was pretty interesting. So this muscle turns on, okay. When this muscle turns on, the arm begins to move. But there are a bunch of anticipatory contractions going on at different parts of the body. When those muscles are tired, that is actually earlier. And so there is an earlier onset of that anticipatory postural adjustment when the muscles are fatigued.

And you say, well, why would that be? Well, if they are fatigued, then they probably don’t generate force as fast and so they need more time. And so this is even more amazing. That the body doesn’t just anticipate the consequence of your action, but it also anticipates the ability for it to compensate for that based on the state of the system. So when your muscles are really tired, the brain seems to know that it better turn those glutes on earlier because it is going to take it longer to generate the force necessary to stabilize you before you actually do the movement that you were intending to do. That’s amazing to me. All that is going on without your awareness.

James Loy:

It kind of seems crazy to me to think how all this is going on. I mean, just your simple example of standing and extending both arms straight forward. That’s not even considering all the different movements we make all the time, simultaneously. It’s crazy to think about how deep that rabbit hole of complexity might go.

Dr. William Berg:

Exactly. And so in a reductionist laboratory setting like we use, just to make sure we are isolating what we want to study, it is amazing enough. But then put that in the context of real world action where you have multiple limbs moving at the same time, and perhaps multiple contradictory perturbations, or disruptions, to your posture, then, yes, you are down the rabbit hole to a complexity that we really can’t even imagine. But clearly our brain handles it.

James Loy:

So, yeah, the brain is obviously directly involved in movement . . .  But, I guess, this makes me wonder if this is actually movement research? Or is brain research? Or, I guess, another way to put that would be, could other scientists, maybe those who study neuroscience, for example, be doing this same kind of work?

Dr. William Berg:

Yes. Or you could be in the engineering school and do . . . there are people in engineering who do movement research. So movement is so pervasive. It’s why I like to teach movement. Because it is impossible not to get a student interested in movement. Movement is essentially necessary for life, so it is impossible not to make it relevant.

But you can come at movement from any variety of approaches, and not just the brain. There is a whole theory that suggests that most of what we observe in human adaptable movement is self-organized. Not unlike water boils when you raise the temperature, it is state of action changes in a predictable way. That’s called self-organization and there is fairly compelling evidence that our movements can self-organize as well.

There is one example that I think is cool. So there are things called passive dynamic walkers. If you google that, and you go to YouTube, you’ll find these little things on treadmills and they are just little legs. They look like us from the waist down, but they are just mechanical systems. It is just us in a little mechanical system. There are no motors, no computers. Just hinges and limbs. And when they turn the treadmill on and give it an incline, which gives it energy, these guys will walk along. They walk. But there is no brain. There is no motor. No magic dust that we know of coming down and making them move like us.

So when I show the students these videos I say, “What does this look like?”

And they say, “It looks like us walking.” And I say, “Well, that’s what most people would say. It walks like us.”

But then I say, “Maybe we walk like it does.”

And that is usually too deep. But the point is that this thing is walking like us not because it has our brains. It doesn’t have our brain. It is walking like us because it has the same physical structure and it is being imposed to the same constraints that we are. So maybe we don’t walk like we do precisely because the brain tells us to do that. Maybe we walk like we do because we live in this particular gravitational environment, and we have this particular physical structure.

So we cannot attribute all of our skill and complexity and adaptability to our brain. This gets you even further down the rabbit hole. So what we ultimately also have to understand is not just how sophisticated the brain is at predicting what is going to happen, and telling your body what to do and perceiving what it is doing, but we have to understand how the brain learns to take advantage of the intrinsic properties of the environment. Because that’s one thing that happens with learning too. So how does the brain learn to take advantage of our current gravitational environment? In other words, get stuff for free? And that is even one step removed from the complexity that we have been talking about. 

James Loy:

And that even seems to bring in the notion of evolutionary biology too. Like, for example, maybe if someday we had a population in the far future that is on a different planet, with different physics and there was a newborn with “Earth” physics programmed into its brain but now growing up in this new environment, would the brain of that person still grow up to walk the same way? Or would it somehow reprogram itself or adapt? 

Dr. William Berg:

Yeah, and for example, if you look at astronauts who come back to Earth sometimes when they get off the plane they don’t walk very well because they have de-adapted, if you will, to our gravitational environment. So part of learning is not just the brain prescribing . . . what I try to convey to students is what you see when you watch people move is not the brain precisely telling them exactly. The brain is also just taking advantage. So when I want to put my hand in my pocket. All I have to do is turn this muscle off. You don’t have to imagine that the brain is contracting all of the other muscles – unless I want to do it quickly – so what I am trying to say is that you could also be in physics studying movement. Because that’s kind of the dichotomy in my field, those who ascribe to the idea that the brain prescribes. 

So there are these programs, like computer programs, in our brain telling every part of our body what to do at any particular time. We know that’s how computers work. Maybe we work something like that. And then there are those who say, no, most of what you see is this organic self-organization. What’s true is that it is probably a combination of both.

James Loy:

I have to say that I never considered how deep and profound of a mystery movement actually is before, but you explained it in such a way that made even me easily understand how intriguing it all actually it is . . . and how complex! 

Dr. William Berg:

Well, good, I’m glad.

James Loy:

And thank you again for your time, and for talking to us and for explaining this to us.

Dr. William Berg:

Alright. It was good talking with you.

James Loy:

You too. Thank you.

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