SELF | Deep Dives
Exploring how to develop our SELF through health, wealth, and connection.
SELF | Deep Dives
Nikolai Bernstein's Levels of Motor Control: Understanding How We Move | Ep. 05
Nikolai Bernstein's essay on dexterity reveals how our movement develops through four evolutionary levels, from basic balance to complex actions requiring multiple brain systems working together.
• Level A (tone/statokinetic): The ancient foundation controlling balance, muscle tone, and trunk/neck stability
• Level B (muscular-articular links): Controls rhythmic movements and synergies like walking, facial expressions, and background adjustments
• Level C (space): Manages precise spatial movements like pointing, reaching, grabbing with a focus on external targets
• Level D (actions): Orchestrates complex chains of meaningful movements unique to humans
• Dexterity requires at least two levels working together - a leader determining goals and background systems providing support
• Human development follows these levels - starting with basic control and gradually mastering complex skills throughout childhood
• Our everyday movements use multiple systems simultaneously, with ancient fish-like balance mechanisms supporting uniquely human actions
What new insights do you have about your own dexterity? We encourage you to explore which specific levels or skills you're most curious about developing further.
All right. So you know that feeling like when you're watching someone about to jump out of a plane.
Speaker 2:Oh yeah, that like heart in your throat moment.
Speaker 1:Totally and then they just go and it's like calm, controlled, that image right there. That's how this essay we're looking at today starts off. It's Chef 5 Dexterity and its Development by Nikolai Bernstein, and he really zeroes in on that shift, you know from that like clenched fist tension to this almost serene control and free fall. It's such a cool way to show how differently our bodies can handle movement.
Speaker 2:Yeah, it's brilliant, right, Like that gut reaction, the fists versus the incredibly precise movement a skydiver makes. It's a perfect intro to what Bernstein's getting at how we learn to master our movements bit by bit.
Speaker 1:Absolutely. You send us this essay and we were blown away by how he breaks down something we never even think about, you know like all the stuff going on behind even simple movements. So that's what this deep dive is all about really pulling out the core ideas from Bernstein's levels of construction of movements and how they lead to dexterity kind of like seeing the hidden blueprints of how you move.
Speaker 2:And the big thing here is that Bernstein's proposing like a system, a hierarchy. It starts with the most basic ways our muscles work and goes all the way up to the most complex, purposeful actions. We'll be tracing that whole path today.
Speaker 1:Awesome, let's start at the very beginning. Then Level A, the level of tone, which Bernstein also calls the statokinetic level.
Speaker 2:Right. So this is, as he puts it, the basement of all backgrounds for movement. It's working like constantly, but mostly we don't even realize it Like the foundation of a building. You don't see it, but it's crucial. This level is mostly dealing with the muscles in our trunk and neck, keeping us balanced. That's the statokinetic, kinetic part. So even before you decide to move, your body's already working hard at this level just to keep you upright and this is where it gets super cool.
Speaker 1:I think bernstein links this all the way back to like our fishy ancestors, you know. Yeah, that prey mother fish idea makes sense right in water balances everything. An early movement would focus on the trunk and neck before limbs even fully developed.
Speaker 2:It's a brilliant connection right. Level A all about stabilizing the trunk and neck, just like those early vertebrates. And think about those moments when you're briefly in free fall, like the very start of a parachute jump or leaping off a diving board or a ski jump. That's level A kicking in making sure you're balanced before everything else takes over.
Speaker 1:Whoa, yeah, it's like for a second. We're back to that primal need for balance, and Bernstein contrasts those smooth, longer movements of the trunk and neck from level A with the sharper, stronger movements of our limbs which are controlled by these younger levels, as he calls them.
Speaker 2:And the way level A actually works, even on a physiological level. Hence and its ancient origins. Bernstein points out that it mostly uses chemical signaling, kind of like the smooth muscles that control our organs, way slower than the electrical signals in the newer levels.
Speaker 1:So it's not like zap instant signal, it's more like a slow burn. And this is how Level A creates what he calls tonic contractions in our muscles, those skeletal muscles we use to move Smooth, slow contractions that give us our baseline muscle tone.
Speaker 2:And that muscle tone is crucial. It's like level A is. Setting the sensitivity level right Makes our muscle fibers more or less ready to fire, so we can control our strength much more finely.
Speaker 1:Like the stage is being set before the actors come on. Right, right Setting the mood. And level A also has this crucial job of coordinating opposing muscles at a joint like your bicep and tricep in your arm. Bernstein compares it to the valves in a steam engine, smoothly switching between the flexor and extensor muscles.
Speaker 2:Exactly that balance between activating and inhibiting muscles is what makes our movement smooth and controlled, and if Level A is not working right, you get like either stiffness and trouble starting to move or the opposite being too loose and weak.
Speaker 1:So when it comes to dexterity, then where does level A fit in?
Speaker 2:Well, it's not directly controlling our fancy hand movements, but Bernstein's argument is that without level A working properly, without that base level of muscle tone and stability, dexterity can't really exist. He makes this great analogy like you need rain for wheat to grow, to make flour to bake bread. Level A provides the necessary environment for dexterity to even happen.
Speaker 1:Love that analogy. It's like this invisible support system, always running in the background, and it's mostly involuntary, right, like our autonomic nervous system that controls our breathing and stuff. We don't think about our muscle tone, but it's mostly involuntary, right, like our autonomic nervous system that controls our breathing and stuff. We don't think about our muscle tone, but it's always there making our movements possible.
Speaker 2:Exactly Now, ready to move up to level B.
Speaker 1:Hit me with it. What's level B all about?
Speaker 2:So level B is the level of muscular articular links, or what Bernstein also calls the level of synergies. It's the level that evolved for like moving around on land and in the air. He calls it a contemporary and partner of the extremities. He even uses this awesome image, you know, describing a sprinter like they're an alien traveler with powerful segmented rods or legs. It makes you appreciate the insane amount of coordination going on, even when we're just running.
Speaker 1:It really does right, like all that's happening without us even thinking about it, and level B has its own evolutionary story. Yeah.
Speaker 2:Oh, yeah, for sure. Like it goes way back from those early nerve clusters and arthropods to the midbrain invertebrates and then, as our brains got bigger, encephalization level B took on more of a background role.
Speaker 1:So it's like the experienced veteran of our nervous system, and it was the first level to use those rapid fire nerve impulses to create what's it called Titani, those strong, sustained contractions like when you hold on to something really tight.
Speaker 2:Exactly that sustained grip. That's level B doing its thing.
Speaker 1:Yeah.
Speaker 2:And this is also where those sensory corrections really come into play. We've got those motor control centers like the palatums and sensory relay stations like the thalamus all working together.
Speaker 1:The thalamus is key here. Right Bernstein describes it as the center of all the body receptor mechanisms. It's getting info from everywhere touch, pressure, pain, temperature and, importantly, proprioception knowing where your body is in space. Even though its old name visual prominence focuses on sight, it's actually dealing with all those senses, so it's like the central hub for all that sensory data.
Speaker 2:Exactly. It takes all that raw data and uses it to create these huge coordinated movement synergies like running, jumping, swimming, even complex stuff like wrestling or gymnastics.
Speaker 1:Wow, that's a lot of information to process. So then, with encephalization, when those pathways for our distant senses, like sight and hearing, moved up to the cortex, did level B kind of lose some of its control?
Speaker 2:In a way, yeah, it couldn't really control things independently as much anymore, but this also really solidified its role as this super important background level. Bernstein does note that it's kind of weak-sided, though, when it comes to those distant senses.
Speaker 1:Makes sense. So for us humans now, what are the main things? Level B is in charge of.
Speaker 2:It's still the boss of those big muscle groups making sure our movements are smooth and flow together. It controls the rhythm of things like how our flexor and extensor muscles alternate when we walk, and Bernstein talks about this uh, minted identity of level b movements, like how similar each step is when you walk normally. This consistency is like the basis for how we learn and automate basic skills.
Speaker 1:So it's keeping those rhythmic actions going smoothly. But we talked about how it's not so good with vision and hearing. So it's great at the internal stuff but not so much when it comes to adapting to, like, sudden changes in the environment, Like if you're walking and the ground gets uneven.
Speaker 2:Yeah, great point. That's where Bernstein's analogy of the airplane mechanic versus the pilot is so helpful. Level B is like the mechanic, making sure all the plane systems are working perfectly, but the higher levels, especially level C, are like the pilot, navigating based on what's happening outside.
Speaker 1:I love that. So level B is working behind the scenes, but can we like consciously influence it at all?
Speaker 2:A bit more than level A, yeah.
Speaker 1:Yeah.
Speaker 2:And it's also constantly learning from our movements, building up this like library of background adjustments, the automatisms that help the higher levels do their more complex stuff.
Speaker 1:So a well-developed level B with lots of these adjustments stored up means you're better at moving and learning new skills, which is like a big part of dexterity, right.
Speaker 2:Absolutely. But it's important to remember that level B itself isn't dexterity. It's more like the groundwork, the foundation, what Bernstein calls body dexterity.
Speaker 1:Right, the potential for dexterity. So what kind of movements does level B actually control on its own then?
Speaker 2:It's a pretty short list but interesting Things like facial expressions, pantomime, those expressive movements we do, and things like stretching, yawning, even little habits like scratching your head or fidgeting. He even compares them to a dog wagging its tail.
Speaker 1:Haha, love that. It's not a ton of actions, but it's doing so much work in the background that we never even notice.
Speaker 2:For sure. All right, ready for level C. This is where things get really interesting, I think.
Speaker 1:Bring it on Level C, the level of space. It sounds like this is where we start seeing those more deliberate, purposeful movements that we think of as dexterity.
Speaker 2:Yeah, you got it. This is the first level, with a lot of independent movement control, not just background adjustments. Bernstein emphasizes how crucial it is for, like athletic movements, anything involving moving through and interacting with the space around us. But it's also a super complex level because evolutionarily it's in this weird in-between state. It's going through what we call encephalization, shifting control from older brain structures, the striatum, to the newer cortical motor system. Bernstein even says it's sitting on two chairs.
Speaker 1:So it's caught between those older automatic systems and the newer, more conscious control from the cortex.
Speaker 2:Exactly, and understanding that really helps to explain why some movements feel both kind of natural but also like they take effort, and even animals that haven't fully made this transition, like eagles or falcons, they're amazing at controlling space right Like super precise.
Speaker 1:They are. So. Even without level C being completely modernized, they can still be masters of movement.
Speaker 2:That's because the origins of level C are all about moving onto land and into the air. First it was about locomotion, just getting around, but then it expanded to using limbs and those distant senses like vision and hearing, those telereceptors to really manipulate the external world.
Speaker 1:I see, and because it's got this like dual heritage, it draws on both the extrapyramidal and pyramidal motor systems. So it's got access to all these different types of sensory information, a huge sensory library, as Bernstein called it. He even talks about the visual areas in the occipital lobe, the auditory areas in the temporal lobe and the tactile and proprioceptive areas near the motor cortex.
Speaker 2:And this is where that space field idea comes in. This is like our brain's internal objective map of the world around us.
Speaker 1:Yeah.
Speaker 2:It's built from all the senses, but also our past experiences and memories. Even when the raw sensory data is messed up like visual, perspective makes things look bigger or smaller, our brain creates a stable, unified space.
Speaker 1:It's like our brain is constantly making adjustments to give us a reliable map right. So level C movements are happening within this mental map of space and Bernstein describes them as often being really efficient. Short, he even says chamber music of the muscles, ha ha. Purposeful, focused actions like pointing, reaching, grabbing, throwing, each with a specific goal in mind, very different from those more automatic movements of level B.
Speaker 2:Yeah, totally Like level B's. Movements are often less about achieving a specific outcome in the world. Level C is all about accuracy and precision. Think about balancing on a beam or hitting a tennis ball perfectly, and Bernstein has this interesting observation about how the end of a level C movement is super accurate, even if the path your hand takes to get there is different every time. Like reaching for a matchbox, it doesn't matter how you get there, as long as you grab. It Shows how level C is focused on the spatial target.
Speaker 1:I never thought about it like that, so it's about reaching that specific point in space In all our experience at level C. It lets us do the same thing in different ways. It's adaptable.
Speaker 2:Exactly, and this focus on the external world is why some level C movements might look a little awkward or less smooth at first. It's not about internal efficiency, like level B, it's about getting things done out there.
Speaker 1:And that adaptability also means you can switch strategies right, like use different limbs to reach the same thing, change how you're moving a musician playing different instruments.
Speaker 2:Yeah, and think about athletes like a skier using different techniques on different slopes. This flexibility is a big part of what makes us dexterous.
Speaker 1:And the sheer variety of movements Level C controls is insane Walking, running, swimming, crawling, climbing, jumping, all kinds of locomotion. Then you've got whole body movements that aren't about moving around, like gymnastics, acrobatics, ballet, and then those super precise movements of our arms and hands Fingers ran along keys, Bernstein says which is just such a cool image Pointing, reaching, grabbing, throwing which is just such a cool image Pointing, reaching, grabbing, throwing, even forceful movements like lifting weights or swinging and throwing motions, both for power, like a hammer blow or throwing a shot put, and for accuracy, like a dart throw or pitching a baseball.
Speaker 2:And even those seemingly simple actions can have different levels involved. Like Bernstein talks about how girls and boys tend to throw differently, showing the difference between level C's spatial focus and level B's more whole-body coordination, and then he brings up mimicking how a monkey, even at its highest level of control, which would be Level C, can't perfectly copy those complex, purposeful human actions.
Speaker 1:Which brings us to Level D right, the level of actions. This is where we really get into the human level of movement.
Speaker 2:This is the big one. Yeah, level D is a huge step up. You might see hints of it in some mammals and more in apes, but it's in humans that it really explodes. Bernstein defines actions as like chains of movements linked together to solve a problem, and the key is each movement in the chain is connected by the meaning of what you're trying to do. Miss a step or do them in the wrong order, you fail.
Speaker 1:He uses this great example of lighting a cigarette. Sounds simple, but it's actually something like 20 separate movements, all in the right order, and you have to adapt them depending on the situation. He also gives examples like getting dressed, washing up, cooking, even more specialized stuff like operating machinery, or those complex moves and sports.
Speaker 2:That chain-like structure is important because you know, we often need multiple steps to get something done. Even with our fancy hands we can't do everything in one motion. And the human hand, which has evolved so much through using tools, it becomes like this super versatile instrument you can do all these different actions linked together. Specialized systems can be super fast at one thing, but the hand's power is its adaptability to do these chains of actions.
Speaker 1:And unlike level C, where using an object is often just moving it around, level D actions are about changing the object right Lighting the cigarette, cooking the egg, shaping clay, even scoring points in a game. It's not just about where the object is, it's about what you're doing to it.
Speaker 2:Exactly. There's this deeper meaning behind the movement, and this is where level D gets super interesting. Bernstein points out that sometimes you have to do things that seem like backwards to achieve the goal, like tightening your belt to unbuckle it, or putting your fingernail under a suction cup to get it off, or even stepping back from a chair to reach something.
Speaker 1:It's counterintuitive. Right Like why move away from what you're trying to get?
Speaker 2:Yeah.
Speaker 1:And he contrasts this with how animals or little kids act, more like level C, just going directly for the goal A chicken pecking at food or a toddler trying to pull a toy apart, directly versus an older kid who figures out. You have to twist it.
Speaker 2:Yeah, those seemingly illogical steps. That's a real sign of level D understanding the whole action, not just the immediate spatial relationships. And he even includes speech as a type of chain action, all those precise movements of your tongue, lips, vocal cords, creating meaning together. And he even mentions angles. Who connected labor, speech and brain development? And guess what? Our speech centers are in level D brain areas.
Speaker 1:So it really is the human level and it's totally tied to the cortex, unlike level C which still has those older connections.
Speaker 2:Right. Level D develops alongside the evolution of new areas in the cortex and it's closely linked to our hands, our main tools for doing all this complex stuff. It's like they evolved together Better hands led to a more advanced level D, which led to even more sophisticated hand use.
Speaker 1:It's a beautiful cycle and this is also where we see that asymmetry in our hands right. Usually the right hand is more dexterous.
Speaker 2:Exactly. That's connected to the left side of our brain being dominant for a lot of things, including speech, and, interestingly, this asymmetry is really specific to level D actions. Those lower levels are more symmetrical, like animals without a fully developed level D and even baby humans before level D kicks in, their brains are more symmetrical.
Speaker 1:Wow. So our right hand, being better at those complex actions, actually makes it better overall, even at those lower levels.
Speaker 2:Wow, right. And when we talk about corrections and automatisms at level D, the main corrections are driven by the overall plan, the big picture. The details get passed down to those lower levels and this is how we get what Bernstein calls higher automatisms. These are specialized sequences of movements that level B and C learn to do really well because level D keeps asking them to. It's like they become experts at their specific tasks. And these are the basis of all our skills, and they mostly run on autopilot, only needing conscious input when something goes wrong or changes unexpectedly.
Speaker 1:So it's like you practice something enough and it becomes second nature, right? Those higher automatisms become part of the movement itself, and they can be pretty complex, themselves made up of lots of smaller movements from those lower levels.
Speaker 2:Now, having gone through all these levels, we can look at how Bernstein classifies different types of dexterity. His main point is that you need at least two levels working together for true dexterity One level, the leader, that's figuring out the problem, and one or more background levels providing support and precision, like a rider on a well-trained horse. And he says level B, since it doesn't control that many independent movements, it can't really create dexterity on its own.
Speaker 1:So Bernstein says humans have two main types of dexterity body dexterity and hand or object dexterity right.
Speaker 2:Exactly, body dexterity is mostly level C, the space level, with level B providing the background support. So CB, think of like a sailor climbing the rigging, someone grabbing a falling apple, a horseback rider, a gymnast doing a jump, an acrobat doing a somersault.
Speaker 1:And then hand or object dexterity is those level D actions with support from the space, sublevels C1 and C2, and sometimes level B2. So DC1, c2, b. More complex, like a soldier unjamming a gun DC. A watchmaker placing a tiny gear DC2. A nurse bandaging a wound DC1. A skier doing slalom DC2. Even more complex stuff like a rider picking up a dropped weapon with their teeth or a bullfighter making a precise strike DC2B.
Speaker 2:And Bernstein even uses that image from the book Prince Sir Brunny, with Meliuda doing this crazy fighting move combining a punch, a kick and a jump. That's, using all those lower levels to support a level D action, dc-1. He also mentioned other examples like fencers, boxers, surgeons, leather workers all needing that high level of coordination.
Speaker 1:So cool, he even breaks down level D actions into different types, depending on which lower level is mainly controlling those leading movements, those higher automatisms.
Speaker 2:Yeah, he has five groups. The first group is like actions without those well-developed automatisms yet. Think of a little kid exploring a new toy, or someone just starting to learn a skill not really dexterous yet.
Speaker 1:The second group is all about the upper sub-level of space C2. It's all about accuracy and precision, like threading a needle, carefully pouring medicine, sharpening a pencil, fixing a watch, engraving, doing precise assembly work, using those delicate tools. It's controlled, visually guided, very fine movements. Also includes those games that need steady hands, like balancing things.
Speaker 2:Then group three shifts the focus to the lower sublevel of space C1. This is more about smooth, adaptable, sensitive dexterity. Often involves moving around or handling objects close to you, like tying your shoes, ironing clothes, rolling dough, shaving, brushing hair, even lighting a cigarette. It's more complex than you think Coupling train cards, driving, filing or polishing something, doing laundry, climbing, cycling, rowing, balancing stuff on your body. Often uses level B for support too.
Speaker 1:So it's less about pinpoint accuracy and more about like feeling your way through the movement Exactly.
Speaker 2:It's adaptable, it's smooth, it's about coordinating with your immediate surroundings.
Speaker 1:I like that. So what about group four?
Speaker 2:Group four is where level B, those background synergies, really take the lead in guiding the movement. Things like tying knots, knitting, winding yarn, braiding hair, washing dishes, getting dressed, hammering, digging, tying things together using a winch or windlass, and then even things like French wrestling and judo, where it's all about leverage and whole body movement and sleight of hand.
Speaker 1:So it's less about precise hand movements and more about coordinating your whole body right, Exactly.
Speaker 2:And then we have group five, the most complex one. This is where both sub-levels of space C1 and C2, work together with level B, super coordinated, and Bernstein splits this group further. First, c1 plus B actions like sewing by hand, sawing, winding a watch, peeling things, mowing the lawn using a sewing machine, tailoring, loading paper, bandaging, wrapping, tying, skiing, slalom, acrobatics, fencing, defense. Then C2 plus B actions like embroidery, darning lace, making fancy metalwork, giving injections using those old fashioned cupping glasses, fencing and boxing attacks, archery, billiards, throwing tricky stuff like boomerangs or lassos, and those examples we talked about the rider picking up a weapon and the bullfighter.
Speaker 1:Wow, that's a lot. So many different combinations.
Speaker 2:And then the most complex subgroup with all the lower levels C1 plus C2 plus B. This includes things like speaking and writing. He says these need amazing harmony and are often found in those really skilled jobs like working with molten metal, firefighting, sailing in rough seas, diving Even in that ballad Schiller wrote the Cup. It also covers those really intense sports or combat situations like bayonet fighting, fencing and boxing as a whole, mountain climbing, hunting, dangerous animals, polar exploration, tricky parachute landings and then those sports that need both body and hand dexterity, like tennis, gerard Key and Lapta. Bernstein even mentions Pavlov was interested in these.
Speaker 1:So even those things we do every day, like talking and writing, are using all these different levels working together. It's mind blowing.
Speaker 2:It really is, and Bernstein also talks about how all this develops in kids from like age two to 14 or 15.
Speaker 1:Oh yeah, that's the second childhood phase he mentions, right After those initial brain changes around age two.
Speaker 2:Yeah, exactly. He says it's not like development just marches forward smoothly. There are pauses, jumps forward even times when kids get clumsier, especially before puberty.
Speaker 1:So what are some of the big changes that happen during those years?
Speaker 2:OK. So between two and three years old there's this huge burst in level D actions. Kids start doing things. Even smart apes can't like taking care of themselves, playing with toys in more complex ways, starting to draw. You usually see which hand they favor by then and they start speaking more clearly. Then, from three to seven, it's more about strengthening and refining all the levels. But they mostly use those easier levels, the basic synergies, level B and that lower space, level C1. That's why they're good at running around doing gymnastics, things like that. They're agile, energetic, good at copying movements, but they get tired more easily with those C2 and D tasks that boundless energy might be, because they can't really do those more focused activities that need those higher levels yet and because level B is so dominant, they move in this really fluid, graceful way.
Speaker 1:They do. It's like they're just naturally coordinated.
Speaker 2:Right, and then from 7 to 10, that upper space level C2, starts getting better. Their movements get stronger and more accurate. This is a good time to teach them practical skills because their brains are ready for it. They can do those smaller, more precise movements like handwriting and drawing, and they get better at throwing and hitting things. Bernstein says it's the perfect time to start musical instruments because they have the basic control, to learn those hand-eye coordination skills.
Speaker 1:That makes sense. And then the teenage years, from 10 or 11 to 14 or 15, big changes again.
Speaker 2:Big time Puberty is happening. Everything's changing. All the levels keep developing but importantly, level D starts getting those higher automatisms, the basis for real skill. This is when teaching them handcrafts and encouraging them to build and create things is really good. Keep training those coordination skills unless there is a medical reason not to.
Speaker 1:So, as we wrap up this deep dive into Bernstein's work, it's just amazing to see how dexterity is this layered system, from basic muscle tone all the way up to those complex actions. It's not just one part of the brain or body, it's all these levels working together constantly.
Speaker 2:And understanding these levels gives you a whole new appreciation for how far we've come, both as a species and as individuals, in terms of movement control. And those like aha moments, realizing how ancient level A is, how level C is still evolving, those weird movements in level D, actions that seem illogical it makes you think about movement totally differently.
Speaker 1:You were curious about dexterity, and what we've seen from Bernstein is that it's this incredible testament to how complex and adaptable our nervous system is. It's built up over millions of years and keeps developing throughout our lives.
Speaker 2:So now think about all the movements you do every day, from just adjusting your posture to those complex actions. You've got a new framework for understanding them. What new insights do you have about your own dexterity, and where do you see these levels of play in the skills you're working on or want to learn?
Speaker 1:This deep dive is just the beginning. Really, there's so much more to learn about motor control and skill development. What parts of our discussion were most interesting to you? We encourage you to dig deeper into those specific levels or the development of skills that you're curious about. Thanks so much for sharing this awesome essay with us and for joining us on this deep dive. It's been a blast.