Steps: The biggest myth in dancing

Sometimes when I'm somewhere where there's music and people are moving to it, I'll ask a friend who I know/suspect might have never had any dance lessons whether she'd like to dance (not *because* she's untrained; because it's fun to dance with a friend!). Understandably perhaps, friends who know that I've been dancing for some years are hesitant because they feel pressure to perform. Even if I reassure them that there's no need for any of that, that it's ok to just move to the music however feels natural and just have fun, I am still sometimes refused because she 'doesn't know any steps' (or at least that's why I'm *told* I'm being refused :->). People often identify dancing with 'dance steps'. Whether or not it's intended, this association places the focus of a dance on what the feet and legs are doing. To 'get the dance right', one only needs to put one's feet in the right places in the right sequence. Whatever the rest of the body is doing is a mere detail. Some readers may have seen the old printed dance instructions where footsteps are drawn on a page, connected with dashed lines and numbered to indicate the order in which one should put one's feet in different places in order to do the dance. This post will discuss this kind of 'step-centric' approach to dancing and propose that a more functional view might be quite the opposite; to put movement first and steps second.

It is common to teach 'moves' in Lindy, Bal, etc, using language that focuses on steps. "Ok, leaders, start with a rock-step, triple-step as you lead the follower towards you. Then, step behind with your right foot as you catch her and send her back in the other direction...." I believe that this kind of language serves to 'discretise' (break up into chunks) peoples thinking about how they move through a 'move'. The process becomes a sequence of small, intermediate goals, which need only be achieved one after another in order to get through the move successfully. So, a dancer learning a move might think, "Ok, step here on 1, then step there on 2, lead over here then step down on 3, hold 4, ......" Combined with this thinking might be a sequence of shapes, which the dancer aims to make as (s)he progresses through the step sequence. So, there might be a notion of the general shape that one should make with one's body when taking a particular step in the sequence. Overall, this way of thinking about a dance seems analogous to the way that a movie is made up of a fast-switching sequence of still images. Dancers are taught all the still images and then are largely left to figure out how best to dynamically connect them. This kind of thinking (and the kind of teaching that encourages it) is very effective at making long sequences of complex movements amenable to memory. It is less effective, I believe, at helping people to progress from 'doing moves' to actually dancing, since good dancing consists primarily in particular ways of generally moving and less in the fine details of the location, orientation and timing of a particular step. I'm not saying those things aren't important; I'm saying they are of secondary importance. Steps are only important in so far as they carry movement (with the exception of deliberately showy footwork - 'steps for steps' sake' - but this too is less important to solid, co-creative partnered dancing than is good movement).

By focusing on the steps to be taken on various beats, a dancer's attention is drawn to only a small fraction of the time for which they are actually moving. An 8-beat move inhabits the full time interval between 8 and 8 and there is a lot of time between the moments we identify as beats. Many good teachers speak of the importance of dancing in the 'spaces' between the beats. I agree with this philosophy. I think that a good way to promote it is to place less emphasis on the beats themselves in the first place. I'm not encouraging arhthymic dancing; I'm encouraging an emphasis on movement, rather than steps. Or, rather, I'm proposing that steps be thought of differently, as tools for the control of movement, instead of as an end in themselves. 'Stepping behind on 4' is not a goal that encourages good dancing. 'Moving your body in such-and-such a way between 3 and 5, and supporting the movement but putting your foot down behind you on 4' is.

Ok, so, it's all very well for me to complain about the the focus on steps, but what are the details of what I'm proposing instead? How, exactly, do steps 'carry movement'? Is there a 'best' way to step? If it's not about position and timing, what *is* it about? Recall the theme of the last post: good communication between partners is facilitated when each partner controls his/her movement in such a way as to minimise the *jerk* of the movement of his/her centre of mass (COM). The remainder of this post will attempt to explain the mechanical details of jerk minimisation through well controlled stepping.

Good dance movement would in many ways be easier if people had somehow evolved to have wheels instead of legs. If we could roll around the floor smoothly instead of having to take steps, it might be easier to deal with the requirement for minimum jerk. But we don't have wheels; we have two fancy, multi-jointed support-sticks that we call legs and we have to learn how to use them in certain ways for good dancing. I think that a useful way to summarise good step control is to say that one needs to learn how to use steps to move one's COM around the floor as if it were on wheels, gliding smoothly through space. This ignores the issue of the rhythmic pulse that shows up in all swing dances but we'll get back to that later. For now, I'd like to ask you to let yourself believe that the basic tools of good dance movement can be learned entirely without rhythm (as indeed, I promise you they can!). We will demonstrate that this is the case by taking a conceptual tour through the detailed process of what we mean by 'taking a 'step'.

Imagine that you're standing on one foot (or actually do it, if you can still read this at the same time). There is a position for your body, with your COM directly over your foot, which feels most balanced and comfortable. But this is not the only position available to you while supporting your weight on this foot. Your foot is not a sharp point, it is more like a flat plate, extending across the floor far enough to give you the ability to stay standing, even if your COM deviates from its central position over your foot. It is fun and useful (and a great workout for your stabiliser muscles!) to explore your range of balance while standing on one foot. Begin in the balanced, central position and then deliberately lean slightly in different directions, paying attention to the way that your weight shifts from the centre of your foot to one side and then the other, as you change your direction of lean. Notice also that it doesn't take much leaning to get your leg muscles working overtime just to keep you vertical. This 'weight shift' corresponds to the changing position of your COM, which is moving as you lean. Imagine your COM as a small marble floating in space, in your tummy, behind your belly button. As you lean in all the different directions, your marble is 'colouring in' a kind of oval shape in space, which contains all of the possible positions your COM can be in while you're standing balance, at this height, on this foot. If you then also allow yourself to bend your knee and play with your balance at different heights, the oval will be extended into the third dimension, becoming a kind of spherical (ok, so 'roughly ellipsoidal' would be more accurate but we can think of it as a sphere) cloud in space. We will call this the 'control cloud' that corresponds to the step you're standing on. To clarify the definition: the control cloud for a step is the region of space in which your COM can exist while having its motion controlled by the muscles in the the weighted foot.

As you move around from one step to another, whether you are walking or dancing, your COM is floating between the control clouds of different steps. The most important thing for us to realise is that the degree of control available to you is *not the same* everywhere in the cloud. Control is much better when your COM is close to the centre of the cloud and tapers off as it moves ever further away. Accordingly, it becomes more difficult to make sure that you are moving with minimised jerk if, on every step, you allow your centre to stray too far from the centre of the cloud. Of course, eventually control disappears altogether and you will fall over if you lean sufficiently far without taking another step. The art of controlled stepping for good dance movement, which facilitates good communication between partners, requires a dancer to learn how to step in such a way that his/her COM never strays from the region of good control for each step. Two things help with this: The first is simply extending one's region of control through experience and training. There are exercises which one can do to learn how to better control the motion of one's centre through a larger range of movement per step. Simple muscle development also helps. The second thing to learn is step spacing. No matter how controlled you can be with each step, if you want to move across the floor, you will eventually need to replace one step with another. It is common amongst beginner dancers that steps are irratically spaced; sometimes unnecessarily close together, sometimes too far apart. By contrast, experienced dancers know how to space their steps so that they are able to maintain a high level of control over the movement of their COMs. The guiding principle in 'planning' (it is usually done subconsciously by experienced dancers) the right step spacing is to always take as few steps as possible in order to achieve well-controlled movement.

As a simple exercise to demonstrate all of this to yourself, try this: Stand on one foot and keep your other leg underneath you, slightly bent, so that your foot is just off the floor. Now, play with your balance for a moment; move your centre around within the control cloud of the step you're on, noticing that fine control feels ever more difficult, the further you move your COM from the point directly above the centre of your foot. Now, to experience a finely controlled step, try the following: Slowly move your COM in the direction of the leg you're not standing on (ie. if you're standing on your right foot, use your right leg to slowly push your COM towards the left). Keep the unweighted foot *directly under you*, just hanging there, moving with you as you control your motion with your weighted foot. As your COM approaches the limit of the well-controlled region of the current step's control cloud, reach out slightly with your unweighted foot in the direction of your motion, lower it to the floor and transition some weight onto it (but just a little bit! Aim for a 90/10 split between the old step and the new step). [Side note: It is sometimes taught that a dancer should not reach out with a foot to take a new step. This is not true; if the dancer is aiming to move across the floor, there is always some reaching. It's also true, however, that reaching *too far* hinders well-controlled movement. The important quantity to focus on getting right is step spacing.] What you have done by putting the new step on the floor is established a new control cloud for that step, which *overlaps* with the control cloud for the old step. Your COM is now still within the reasonably-well-controlled region of the old step *and also* at the far reaches of the not-very well-controlled region of the new step (hence the 90/10 split between the old and the new). Now, keep your COM smoothly moving towards the well-controlled region of the new step's control cloud. Notice the weight split gradually shift between your two feet as your COM moves: 80/20, 70/30, 60/40. *If you have spaced your steps optimally*, by the time you get to 50/50, your COM will be right at the edge of the well-controlled regions of both steps at the same time, passing from the old and into the new. You can test this by lifting either one of your feet of the floor. You should feel like you're going to fall over but 'only just'. If you have spaced your feet too widely, you will feel like you'll definitely and quickly fall if you lift either of your feet off the floor. If you have spaced your feet too closely (arguably, this is not as problematic as spacing them too far apart, because closely-spaced steps can be easily controlled. Still, they are not without problems, as we shall see), you will feel as though you could lift either foot off the floor and still stay standing by only making a tiny adjustment to the position of your COM (and, you won't have moved very far with your step!) Keep moving your COM gradually until your weight is 100% on the new step (ie. your COM is now directly over the centre of the newly weighted foot). The overall effect of this stepping process has been to provide an unbroken passage of good control between the maximally balanced positions of the two steps, meaning that stepping in this way ensures that the motion of your COM is always well controlled, as required for good dancing.

Before rounding up this post I would like to discuss a stepping habit with which many good dancers sabotage their ability to work well with their partners: Taking too many steps. It is natural, especially for an inexperienced dancer, to want to spend as much time as possible within the safely balanced, well-controlled region of each step. One can manage to do more of this while moving around the floor, simply by taking more steps and spacing them more closely. The same speeds and trajectories can be achieved in many cases, but the dancer feels more controlled. The trouble with this strategy is that it removes options for communication between partners. Every step is a commitment to a position on the floor. It can be a lot of fun to flirt with a step without actually committing to it; to move in one direction only to stop before stepping and go back the other way. It is also fun to add rotations/swivels into steps to make trajectories more interesting. Stepping earlier than required can cut off both of these options, which can be very frustrating to a partner who is trying to 'enjoy the spaces between the steps'. Again, the guiding principle should always be to take as few steps as are necessary in order to maintain well-controlled movement that facilitates good leading and following. I like to teach the mantra, "Never hesitate to move. Always hesitate to step."

For several posts now, we have discussed the art of partner dance movement. In the next post, we shall progress to the next chapter: connection.

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Movement 2: Communication through predictability, fun through unpredictability

I remember feeling that my understanding of 'dance mechanics' made a leap when I realised that the physics of each partner's body is a slave to the need for communication with the other partner. The partnership comes first; individual freedom within it, second. Understanding the communication then, is essential to understanding the physics obeyed by each partner in order to make that communication possible. When two people dance as a partnership, they are constantly sending and receiving information between them through vision, hearing and touch. Each partner (in most cases) can see, hear and feel what the other is doing and on the basis of all that information, can predict the trajectory of the partner's dance into the near future (on the order of a fraction of a second to a few seconds, depending on parameters like tempo) and make plans about how to cooperate with it. This post will begin with a simple introduction to the ways in which the human nervous system deals with sensory signals - how it notices things, uses what it notices to make predictions about what new things might come next, and ultimately 'gets bored' when those predictions are consistently easy to make. I must stress up front that this introduction will be pseudoscientific, making specualtions based on a few basic facts taken from real perceptual science. (I will pitch things at this level because to attempt a rigorous account would require vastly more research on my part and also because I don't think that going into all that detail is useful for our practically-focused purposes. Nonetheless, if you know that something I've written is at odds with the established science, please let me know so that I can correct it.) After their introduction, these ideas will be applied to a discussion of dance movement. The emphasis at this stage will be only on visual communciation between partners; tactile communication ('connection') will be covered later. Three physical principles of good dance movement will be presented, one which applies when following, one which applies when leading and one which applies in both cases, ie. all the time. Ultimately, it will be argued that good dancing maintains a tension between predictability at one level, and unpredictability at another, though it is the need for predictability on short time scales that governs what has come be taught as good dance movement.

The human nervous system is sensitive to change, not constants. Have you ever had the following experience?

You're about to go out for the day and you slip the usual things, like keys and wallet, into your pockets. It's been too long since you cleaned out your wallet and when you sit down on it - to drive somewhere, say - it's a downright uncomfortable, bulky lump. But within a couple of minutes your attention is elsewhere, you've stopped noticing the lump and can sit comfortably. Then, as you approach your destination and have long since forgotten about absent-mindedly grabbing your stuff on the way out the door, or the discomfort of the lump in your pocket when you sat down, you are suddenly hit by a worry that you might have forgotten to bring your wallet with you. In an attempt to check, you bring your attention to the delicate meats of your hind quarters to see if you can feel a wallet between them and the seat below. Nope, nothing. 'But I thought I grabbed my wallet on the way out!' You then reach down with your hand to double check and voila, there's your wallet!

Or how about other experiences like these: You walk into a restaurant and are struck by the smells of a menu-full of dishes all around you but after a couple of minutes, you don't notice them anymore. You have no trouble sleeping in the same room as an appliance with constantly-lit light on it but a flashing light of similar brightness makes it harder to get to sleep. You are able to concentrate on your work with a loud fan or air conditioner humming away in the background but the unpredictable (and not particularly loud) banging of a distant hammer by your renovating neighbours distracts you persistently.

All of these experiences are consistent with the finding that almost any persistent, unchanging stimulus (ie. signal from one or more of your senses) will gradually become less and less noticable. The gradual decrease in perception of a constant stimulus is known as habituation. Stimuli that change over time - like a flashing light - resist habituation for longer than constant ones, which is why we notice them for longer (the next time you're walking down a street with lots of neon signs, notice that some flash and some don't. The flashing ones are better at grabbing and holding attention.)

The details of the way in which a stimulus varies affect how long it takes a perceiver to habituate. For example, you will stop noticing the regular ticking of a wall clock long before you stop noticing the irregular hammer-banging of rennovating neighbours. This means that your brain, in processing information from your senses, is sensitive not just to changes in that information but changes in the changes. ie. A constant hum does not change. A ticking clock changes, varying from sound to silence at a constant interval with each tick, but this pattern of change is constant (the ticking interval does not change). Random hammering changes from sound to silence with each bang and this change is changing randomly; sometimes the hammering will be frequent, sometimes there will be long silences. In this latter case, because the signal (the sound from the hammer) is assumed to be (perfectly) random, it is impossible to predict, by definition. When you hear one bang, you cannot know when the next one will be heard; it may come soon, maybe not. By contrast, if we assume that the clock's batteries will never run out, then the clock's signal is perfectly predictable because its ticking is constant (the changes in the sound are not changing). You can predict when the next tick will happen based on when the last tick - and all the other ticks before that - happened. The random signal of the hammering is subjectively more interesting than the constant hum and the ticking clock because one can never know what's coming next, sound or silence. It 'keeps us guessing'. There is, however, a sense in which even this unpredictability is predictable; once the signal is established as random, it is also established that one will never be able to predict it, so the act of trying to predict it gets boring too. Eventually, one will habituate even to a random stimulus. If your rennovating neighbours keep at their random hammering for long enough, you will stop noticing.

Let us now consider cases in which a person wants not only to pay attention to a signal, but to somehow cooperate with it. For example, imagine you decide to tap your finger on the desk every time you hear a sound, and further, you'd like to make your tap happen as closely in-time with the sound as possible. In the case of the constant hum, the task is so simple and uninteresting that it hardly makes sense; you only tap your finger once when the sound is first perceived and since it never goes away, no more taps are required. One sound, one tap, game over. With the ticking clock, the task is only slightly harder and only slightly more entertaining. After a few ticks in which the rhythm is established, you find yourself able to keep good time with the ticks and the task becomes monotonous. Game over, almost as soon. With the random hammering, the game is impossibly difficult. It is interesting for a while as you struggle to find a predictable pattern so you'll know when to tap. Eventually, however, you will find no pattern and, if sane, will give up.

Although I have no hard evidence to back up my conviction, I think it can be concluded from these simple examples that the most entertaining tasks in which a person attempts to cooperate with some sensory signal are those in which the signal has some predictable components and other unpredictable components. The predictability makes the task achievable while the unpredictability makes it challenging.

Consider a group of jamming jazz musicians (to any accomplished musician readers, I apologise for whatever musical ignorance I may demonstrate in the following). As the musicians play, they each emit an auditory signal (their own music) and each receive the signals of all the other musicians in the group. Their task is to make their own signal combine with all the signals from everyone else in such a way that their combined total signal (the group's music) is pleasant to listen to. For each musician, certain elements of the task are predictable from the outset; the key and the tempo, for example. These provide 'home base' - a place to start from and come back to - for all the musicians; this helps to make the task achievable. What makes it interesting is the unpredictability in the indivdual musicians' choices about rhythms within the beat, melodies within the key, and all the other interesting variations in other musical parameters the can exist within the frame provided by tempo and key.

Now, let us consider the process of making a change in a property of the music, the predictability of which all the musicians are relying on in order to stay together. For example, let's say the drummer decides to double the tempo by the end of the phrase. Importantly, we have stated both a planned end point (a doubled tempo) and a time interval in which to get there. Strictly speaking, there are an infinite number of ways to make the transition. He/she could simply double the tempo within a single beat, at some randomly chosen point within the phrase. Such a sudden transition would be completely unpredictable and so would be impossible to work with for all the other musicians. How can the transition be made as achievable as possible for the whole group? Anyone who has ever watched a band do this together will know that it must happen gradually (unless there is a pre-made agreement between the musicians that it will be made is such-and-such a quick, fancy way). Over the course of the phrase, the tempo is gradually pushed higher and higher in such a way that all the musicians are able to keep track of each other's tempo. In general, the easist way to make such a transition is to make it as gradual as possible. Indeed, it is not uncommon for a whole band to change its tempo unintentionally over the course of a song because the change happens so gradually as to be imperceptible from moment-to-moment. Another way to describe this kind of change is to say that the rate of change is minimised. This allows for mutual predictability between the musicians in such a way that they are able to work together while still being able to play interesting parts (which have some degree of unpredictability) as individuals.

What can we infer about dancing from all this? There are implications for both movement and connection. We will discuss movement now and connection later. In light of the material presented in the last post, we will simplify things by focusing on the motion of each dancer's centre. Just imagine a tiny marble floating in space, located near each dancer's bellybutton. We will consider the motion of that marble to represent the motion of the dancer.

We will now introduce some basic physical concepts of motion. No matter who you are, you will already be familiar with these through experience, even if you've never really thought about them in this way before. The first concept is simply the position of an object. In order to be meaningful, position must always be stated as a distance from some other object (eg. Q: 'Where do you work?' A: 'Three blocks north, up the street from where I live.'); for our purposes, we can think of a change in an object's position and a change in the distance the object has travelled as the same thing. Now, the rate at which position or distance is changing with time is called speed or velocity. Finally, the rate at which speed is changing is called acceleration. That is, acceleration is the change in the change in position as time passes.

Let's apply these ideas to a simple 'thought experiment' with two dancers dancing a Lindy 'swing out'. Using our simple model (as per the last post), we imagine the little marbles at the dancers' centres of mass. The following description refers to the dynamics of those marbles. At the beginning of the swing out, the dancers are momentarily not moving. That is, their speeds are zero. Their positions are located two semi-outstretched armslengths away from each other. Even though their speeds are zero at this point, their accelerations are nonzero because there is energy being passed from the leader to the follower (the leader is leading). Acceleration is the rate of change of speed, so this means that the dancers are speeding up. The following is an important point; try to remember it because we will refer back to it later:

Whenever a dancer is speeding up, slowing down or changing the direction of his or her movement, he/she is accelerating.

After the acceleration period at the beginning of the swingout, there is a brief 'coasting' period for the follower, in which her/his speed remains constant (actually, we will see later that the best dancers minimise this coasting period, usually removing it altogether by linking the speed-up directly to the slow-down). As the first half of the swingout ends, the leader will lead the follower to accelerate again (it's natural to think of this as deceleration because the follower is slowing down but in strict physical terms, it's an acceleration because it meets the criteria of the above definition) until she again comes to a momentary stop. The second half of the swingout is essentially the same process in the opposite direction. This simple little example was intended to illustrate how dance movement can be thought of in terms of the simple dynamic quantities of position, speed and acceleration, all of which change as the dance proceeds.

We are now finally in a position to introduce the three rules of good dance movement that were mentioned at the beginning of this post. These are rules for movement and mention nothing about connection at this point. They may seem counter-intuitive until considered in conjuction with the rules of connection to be discussed a little down the track. We will simply state the rules first and they will then be discussed in the context of predictability.

1) When following, do not accelerate yourself. Rather, maintain the same speed and direction of movement you have 'left over' from the last lead until this is changed for you with another lead. This applies to both straight line movement (the physical term for a straight line movement is a 'translation') and turning ('rotation').

2) When leading, accelerate yourself (NOT your partner). That is, change the speed and/or direction of your own movement.

3) When following and when leading, minimise the jerk of your movement.

Ok, let's start with 3) as you're probably wondering how jerking got into all this. Believe it or not, 'jerk' is a formal physical term, which refers to the rate of change of acceleration. That is, jerk is the next in the chain that goes

position --(rate of change)--> speed --(rate of change)--> acceleration --(rate of change) --> jerk

The name, 'jerk' has stuck because it has intuitive meaning. Imagine picking up a heavy suitcase. However this is done, the suitcase must be accelerated off the ground. However, if it is done in a 'snappy, jerky' way, the rate of change of the acceleration (the jerk, in the physical sense) is high. If the suitcase is picked up in a 'smooth, flowing' way, the rate of change of acceleration is low. It is well known in biomechanics that people will naturally perform many different motor taks in such a way as to minimise the jerk of the masses being moved. One example is picking up a cup of coffee while taking care not to spill anything.

Note that we encountered the principle of jerk minimisation (in a metaphorical sense) in the above description of how a band can work together while changing tempo. If the drummer were to double the tempo within a single beat, the transition would be far too 'jerky' for the rest of the band to keep up. However, if the drummer has decided on a time frame for the transition, he/she can make sure that it happens as gradually as possible (with minimum jerk) over that time interval. This makes it as easy as possible for everyone to work together during the transition.

Stepping back from the musical metaphor and into the physical world of dancing, let's see how 1), 2) and 3) work together in the process of one dancer giving a lead to another.

Step 1: The leading dancer will decide on a desired consequence for the motion of the partnership and the time frame in which this consequence is to be achieved. For (simple) example, a reversal of direction for both dancers. The leader will begin the process by accelerating him/herself with minimum jerk and with enough energy that in addition to his/her own direction being changed, enough energy will also be available to flow through the connection to the follower. During this time, the follower is thinking only about continuing her movement and is not herself changing that movement in any way, even though she sees and feels the leader move his own body, and feels the energy that he is giving begin to alter her motion. The key point here is that she is neither deliberately resisting the lead nor adding to it. Her motion begins to be altered almost instantaneously (the time delay is due only to the speed of sound through their connection, which is pretty damn fast - Yes, literally the speed of sound, like the speed that jet fighters fly at. This will be explained more later, when we talk about connection) but the alteration takes time to build; it arrives gradually, over the period during which the lead is giving energy (ie. leading).

Step 2: After the leader's self-acceleration has begun, it takes some time for the energy to flow through the connection to the follower. The energy does not all arrive at once but gradually, over an interval of time. During this time, the follower allows the energy to gradually accelerate her. She does not add any extra energy to her motion, above what she is receiving from the leader. She controls her reception of the energy in such a way as to keep her movement 'smooth' (minimise the jerk).

Step 3: With the energy transmission complete, both partners now 'move as followers', conserving their state of movement without adding extra energy. When one partner does choose to add energy, doing so will function as the next lead and the energy will again be passed through the connection so that it is shared between both partners and their motion will be changed again.

In this process, we see both the elements of predictability and unpredictability that make for dancing which is both achievable and entertaining. The dancers control their movement so as to be mutually predictable on the time scale in which leading and following happens (less than a second to a few seconds). This allows them to work together through transitions in their shared movement. However, choices about who will lead what and when are largely unpredictable, keeping the dance interesting.

Before ending this post, a special condition should be mentioned. The above rules apply only when both partners are dancing on balance. Counterbalance - where both dancers are off balance in opposite directions in such a way that their imbalances cancel each other and the partnership as a whole remains balanced - is a different story. This will be discussed properly, much further down the track. First, however, it is time to discuss the practical details of jerk minimisation by focusing on the biggest myth in dancing: the step.

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Movement 1: Hairless crash test dummies, simple models of the human body and the magic of its 'centre'

Before proeeding into a nuts-and-bolts explanation of how and why maximum mutual predictability gives rise to good dancing, it is necessary to discuss what is meant by a dancer's 'centre', and why it is important. The goal of this post is to introduce the idea that a complicated physical system, like a pair of people dancing, can be effectively represented by a simple model. This simple model is useful because it is easier to understand than the real system and can be used to gain insight into what makes the complex, real system tick. I will argue that in the case of a dancer partnership, the motion of each partner can be adequately represented by the motion of his/her 'centre', or centre of mass.

In later posts, we will gradually put together a simple model, which I believe effectively represents good partner dancing. If we just launched straight into the model now, it might not be clear where that model came from or why it works, and that might be annoying. So, at this point, it will be useful to first describe the general process of creating an effective simple model for a complicated physical system - like a connected pair of dancing human bodies. We will take a brief step away from dancing and just talk simple physics for a moment to get a feel for the big picture of how we will look at dancing afterwards. Doing this now will help things to make sense as we proceed further down the track. Please don't worry if you've never studied, or even liked, physics. I will do my best to make this as painless as possible. I promise there won't be any equations, at least not yet ;-)

Physics is mostly about describing fundamental relationships in the natural world. The practical process of how this is done usually proceeds something like the following. We will consider a practical example throughout, to help it all make sense. This example - that of using crash test dummies to understand how human bodies move during traffic accidents - might seem a bit gruesome but I have chosen it because it deals essentially with the same question we are facing in trying to model good dancing: How simple can I afford to pretend that a human body is so that I can study its behaviour more easily? Do I need to study a perfectly lifelike model, with all the detailed features of the human body, like hair length, eye colour, etc, or can I get away with studying a simpler model like a 'stick figure', which lacks all these details but still has all the important bits? The process by which we usually answer this question in physics goes like this:

Step 1) Observe something interesting in the world and wonder about how it works - how all the parts relate to each other.

Let's begin our example in an historical context. In the early days of automotive transport, cars were engineered to transport people and stuff, without a lot of consideration for keeping all that stuff safe in the event of an accident. Over time, as more and more people got hurt in car accidents, patterns were identified in the kinds of injuries that resulted. This posed a question - why do these kinds of injuries happen in car accidents, and how can cars be better engineered to prevent them from happening in future?

2) Based on your experience of how things have worked in other parts of nature you're familiar with, identify the essential features of this new system and, for simplicity, temporarily forget about all the stuff you think is probably non-essential.

What are the features of a person's body, which most strongly determine his/her injury risks in a car accident? Based on past experience, you might assume that body mass, size and approximate shape, for example, are more important than hair colour or length of fingernails.

3) Put together a simplified model (often called a 'toy model') in which the system of interest is composed only of the features you have decided are likely to be essential. This is usually done first in one's head and then in diagrams.

I am not familiar with the actual historical process of how car manufacturers went about modelling car accidents and how that progressed over time, but I know that it eventually resulted in sophisticated experimental tests using the iconic (and hairless) crash test dummies that have become familiar to the public. Presumably, things started much simpler than that. The very first crash tests might have just had human-weight bags of sand on the seats, for example. Early theoretical models might have been very simple, just representing a person's body with a simple shape - maybe a sphere or a square-edged box - with the same mass and roughly the same size (so, the same density) as the average human body. It's always easier to start with a very simple model and add in complexity in small steps from once the simple model is understood.

4) Using fundamental laws of nature and mathematics, derive equations that describe the dynamics of your toy model.

If we assume, as speculated above, that a simple model of a human body might be a spherical blob with the same mass as the average human body, then for this step of the process, we would use the laws of Newtonian mechanics (originally formulated by Sir Isaac Newton in the 17th century and still used today for describing how physical objects behave on the everyday size and time scales familiar to humans; ie. not very small like atoms or very big like galaxies, but in between like people in cars) to write down equations describing the behaviour a spherical person in a car accident. These equations are usually then used to generate graphs or computer simulations, which allow for the visualisation of how the toy model is behaving.

5) Compare the behaviour of your toy model to the behaviour of the real system you are trying to describe and note how different they are.

Our spherical person model would probably do a good job of describing the behaviour of a person's body overall but would tell us nothing about the detailed movements of limbs.

6) Revise the toy model, adding in some complexity.

We might add some sticks to our sphere so that the toy model now looks roughly like a body with simplified arms and legs.

7) Repeat 4-6 until the model's dynamics are deemed to be sufficiently like the dynamics of the real system.

We can speculate that over time, this gradual iterative process resulted in the crash test dummies that we have today, which are clearly a lot more like real people than is a spherical blob. However, importantly, these dummies still don't have hair, eyes, individual fingers or toes, or other such details, presumably because it has been decided along the way that including these details complicate things without helping to answer any imporant questions about car safety. Eventually, a point of diminishing returns is always reached at which adding more details to the model makes the science a lot harder without significantly adding to the descriptive power of the model.

Ok, strict physics talk over for now. Phew! Let's get back to talking about dancing! The question I'd like to address in this blog is, 'Is it possible to come up with a simple model, which describes the essential features of good, musical, improvisational partnered dancing, and can the nuts and bolts of that model be used to develop practical tools for improving people's dancing?' I think the answer is yes and I will attempt to show how and why.

In our crash test dummy example above, the very simple model we started out with for a person's body was a spherical blob that weighed as much as the average person. It turns out that we could have started with an even simpler model. Before representing the person with a 3D spherical blob, we could started with a 1D blob, called a 'point mass'. We would prented that all the person's mass were concentrated at a point in space and we would locate that point at the real person's centre of mass (COM). So, we would be replacing the person with a microscopic (actually, infinitely small) marble, hovering in space at the centre of where the real person used to be. Despite being tiny, this marble would weigh the same as the person. This is arguably the simplest possible way to represent a 3D object. I will argue that for modelling dancing, this very simplest of models is adequate for practical purposes. We won't even have to make things as 'complicated' as to pretend that a person is a spherical blob. Instead, we will be able to imagine that a person is simply a single point in space, like a tiny marble that weighs as much as the person it represents.

In my experience, most people have some concept of what their COM is but we need to make sure we're clear here, so let's talk for a moment about what, exactly, we mean by COM. Your COM is the average position of all the mass in your body. Your COM changes as you make different shapes with your body, and it can even be outside of your body. For example, if you're standing up and you bend over to touch your toes, your body (seen from the side) is making a kind of triangle shape and your COM will be somewhere inside that triangle. Since your torso is probably heavier than your arms and legs, your COM will be closer to your torso than your feet. Nonetheless, it is probably outside of your torso, hovering in space just below your ribcage somewhere. When you stand back up again, as your body comes to form a vertical line, your COM will sneak back inside your torso, probably just behind your bellybutton. It is important to understand here that your COM is not a physical object, it is just a number calculated from the positions and masses of all the real parts of your body.

Even though the average position of all the mass in your body is just a number, not a real object, it is very useful because it is the fairest way to answer the question, "Where is my body?" with just a single point in space. If someone wanted to know where you are located in a dark room, giving them the coordinates of your little toe does not very fairly represent the position of your body, because most of your body is located to one side of that point. But reporting the position of your belly button gives a much more useful piece of information because (assuming you are standing straight), it is close to the average position of all of the mass in your body; your mass is located all around it so anyone aiming for that point is likely to find you even if they miss in any direction.

I'd now like to demonstrate the usefulness of the COM in tracking a dancer's movement. Imagine that you are given three videos of a dancer dancing in a dark room. In the first video, the dancer wears a glow-in-the-dark dot on one of her hands and all you are able to see in the video is the motion of the dot, which darts all over the place. In the second video, a similar dot has been attached over the dancer's belly button. This dot moves more smoothly and covers less distance than did the dot in the first video. The last video was shot with a 'night vision' camera, so you are able to see the dancer's whole body. You notice that the overall quality of the dance, when the whole body is considered together, is more like the motion of the belly button dot than the hand dot. This is because the dancer's COM will never be far from her belly button and the dynamics of her COM are the best single-point representation of her whole body's dynamics. Her hand, by comparison, will spend most of its time far away from the dancer's COM and so moves in a way that is unrepresentative of her whole body's motion.

Swing dancers are often taught to 'move through your centre' and leaders are taught to 'lead with your centre'. The reason for this, I believe, is that a dancer's centre (COM) is, speaking in strict physical terms, the heart of their 'identity' as a physical object. When I am dancing and connecting with my partner, the best way for her to know what I am doing is for me to communicate to her what my centre is doing. The rest is details and those details are easy to lose when the very task of sharing control over the dance partnership is so difficult from the start. The business of movement and connection then, is about doing so in ways that clearly communicate to your partner what your centre is doing. As we will see in more detail in the next post, making your centre's movement predictable for your partner will make it easier for him/her to cooperate with you in co-creating the dance.

One final note should be added to this post. Modeling a dancer as his/her COM is the simplest possible model one can construct and in some circumstances, a slightly more detailed model is useful to consider. One can construct an arbitrarily complex model by combining COM models for components of a dancer's body. The next step up from the basic COM model is a model in which the dancer's body is considered in two halves - upper (from the waist up) and lower (from the waist down). Each of these halves has its own centre of mass; we might call these the 'upper centre' and 'lower centre'. As we will see later, breaking things into two parts like this is particularly useful when considering the connection required to lead and follow turns. From this point, we might take the next step up in complexity and explanatory power by breaking the body into six or seven pieces: the torso (in the six piece model; in the seven-piece, the torso would be split into upper and lower torsos), the four limbs and the head. Note, a three-piece model could also be constructed, and would be the next logical step from a mathematical perspective, but the six-piece model makes more sense from an anatomical perspective. This process can be carried as far as we like, with pieces being broken into ever smaller pieces which are modelled as their centres of mass, until a model is created, which is sufficiently accurate to answer whatever question one might be considering. For most practical questions however - the kinds of questions which might help teachers teach and students learn practically - a basic COM model is adequate.

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Moving and connecting as nature never intended

Most readers will be familiar with Windows Media Player's (WMP) music visualisation programs, which splash weird, eye-catching images across the screen, changing in real time to reflect musical dynamics. These might look pretty but they do a lousy job of representing music. If you watched one with the sound muted, how much could you infer about the music? My guess is, maybe some rhythms at best. Dynamic visual representation of music is not easy.

You can dance better than this.

Now consider this: WMP makes its visualisations using just a single computer. The flow of information is simple:

Music --> Interpretation by a single computer --> Visual ouput, one frame at a time.

This is not all that different from what a solo dancer needs do to be musical. The dancer's visual canvas - his body - is controlled by a single brain. Music is heard and interpreted, musical movements are planned and executed. Obviously this is a simplification of the complex physiology at work but the point is, dancing within one body doesn't ask for anything outside the range of normal human behaviour. Millions of years of evolution and a lifetime of experience have trained your brain to hear music and move your body in all kinds of amazing, finely controllable ways, which are readily adaptable to environmental demands like swingin' tunes.

Why is well-connected, flowing partner dancing so difficult? There are lots of reasons of course, but many of them stem from one fact: a single dynamical system (two human bodies trying to dance together as one) is being controlled by two brains, each with its own ways of interpreting music, and has direct sensory and motor connection to only one half of the system. That is, your brain, via your nerves and muscles, can only directly control the half of the dance partnership that is your own body. And yet somehow, the two parts are supposed to closely cooperate to artistically express, adaptively in real time, some compromise between your two different interpretations of the music. It seems impossible! And yet the best dancers can do it well. How can this be?

Over the years, dancers have evolved - culturally, not biologically - systems of movement and connection, that afford them a high level of shared body control. These systems work by constraining the movement options of each individual partner so as to give the whole partnership more options. Not unlike in most relationships between life partners, each dance partner agrees to not do certain things so that the partnership might be able to do more. Later posts will deal with the mechanical details of these self/shared control systems. The rest of this post will describe the guiding principles behind them.




The first principle is that these systems are primarily functional. They are not the way they are because some authority figure in the past said that people must move and connect in certain ways. Rather, these systems evolved for the same reason that all complex things have evolved: they succeeded where others failed. Many dancers, dancing many dances, for many years, through trial and error have developed efficient systems of movement and connection. These allow for a high level of fun and creativity with the least effort on the social dance floor. Interestingly, it has not been necessary to deeply understand why these systems work; for practical purposes, knowing and teaching the how is enough.

So, on to practical matters! As far as I can tell, the main guiding principle behind effective movement and connection is mutual predictability. Each partner needs to move and connect in ways which make it as easy as possible for the other partner to have the experience, "Ahh, I see and feel what you're doing and where you're going with that. I can work with that!" Of course, too much of anything is a bad thing; if you move too predictably (eg. doing the same 'move' over and over), your partner will get bored. A balance must be struck; it's all about time scale: predictability over a few seconds is good, a few minutes, not so good. Perhaps a better word than 'predictability' is 'trackability'; your partner must be able to track what you're doing. But, for the sake of continuity, let's stick with 'predictability'.

Before moving on though, one other point must be made about this word. Reading the word 'predictability' might be setting off alarm bells for you because teachers often stress, to followers in particular, that prediction/anticipation of leads is a no-no. I agree with this. This is different from the kind of prediction I'm talking about. This kind, the kind to be avoided, is less about prediction your partner's movement and more about assuming that you're capable of reading his/her mind. This is sure to lead to dysfunctional dancing because often, not even the leader knows what he/she is thinking; advanced leaders frequently just let the dance unfold and 'go with the flow', often without strict plans for what will come next. Good followers learn how to keep track of their leader's 'flow' (trajectory) without making any assumptions about what that means for the follower. There is no 'supposed to do' in pure following; there is only letting the dance be done to you. If it is not done to you - if your motion is not physically changed for you by energy provided by your leader, with zero extra energy input from yourself (which is a functional definition of pure following) - then whether or not it was intended doesn't matter. Of course, good followers have a huge amount of input into how they are dancing, but they accept that input as their responsibility; it is not an attempt to guess what the leader might be thinking. In summary then, what I am advocating is promoting each partner's ability to track what their partner is doing within their own body, identify a pattern and see where it is likely to lead, without inferring that some particular response is required (that is the kind of 'anticipation' that should be avoided.) If one can avoid feeling obliged to lead oneself in response to something that one's partner has done with his/her body, then prediction is a useful thing because it provides a reference point for one's own self-directed dancing within the bounds of the partnership.

If you can see that your partner is moving is such and such a way and predict where that will take him/her over the next few seconds then you can plan around that in a way that allows you dance with enough independence to have your own fun while always being ready to pass energy back and forth (lead/follow) with your partner. A simple example of this is a good old footwork variation. A good leader will move and connect in a way that usually allows his/her follower to know when has been given enough 'space' to add in a variation without interupting the flow of the partnership. An inexperienced lead, by contrast, will be harder to track and prone to giving the follower the impression that she/he can never quite know what's coming next so it might be unwise to do anything but strictly follow. Of course, predictions can always be wrong, even between the best dancers. What I am arguing is that in general if partner (A) moves and connects in such a way that partner (B) can be reasonably successful is predicting (A)'s dancing into the near future, then (B) will be in a better position to cooperate with (A). (B) should also try to allow the same kind of predictability for (A). A useful analogy here is a squadron of jets flying together. If the squadron is to stay together without constant radio communication ("Ok guys, we're all about to slowly peel left. You ready?"), then each jet must fly in a way that is predictable to the others. There are certain simple, physical rules (like 'no sudden moves', for example) which allow this to be achieved. We will look at these rules in detail in future posts.

I'd like to finish this post with a brief discussion of lead and follow. Splitting a partnership into lead and follow is, of course, the one big pre-agreement that has to be made between the two brains controlling the two bodies in the dance partnership if anything at all is going to be achieved cooperatively. The agreement is simply this: When one partner is passing energy to the other ('leading'), the second partner will allow that energy to flow naturally into their body and be conserved in the process, meaning that it will usually change the way that they are moving. Note that no mention is made here of one person being the leader and the other, the follower. The best dancers will tell you that both partners are both leading and following throughout most dances. A good dance is a conversation, with two speakers and two listeners, not a monologue with one of each. The only restriction is that, just as in a good conversation, the two partners do not try to talk over the top of each other. When one speaks (leads/gives energy), the other listens (follows/accepts energy). Strictly speaking, I believe it is physically possible to both lead and follow at the same time; it's just extremely difficult and not really necessary for the creation of fun dancing.

I suppose that special mention should be made here of historical exceptions. Blues is probably the most conversational of the usual swing-associated styles. I'd say Lindy hop comes in at second place. Balboa, on the other hand, is more traditional and many people feel strongly that is should be role-based as far as lead and follow are concerned. That is, one person leads for the whole dance, the other person follows. End of story. This is a cultural contraint, however, not a functional one. Speaking in strictly physical terms, lead and follow can be shared back and forth in any partner dance. Doing so will make some things possible, which are not possible if the lead is uni-directional. At the same time, it will make other things harder. Presumably, the Balboa community has decided that the latter is too great a cost to justify the former. For whatever reason, Blues and Lindy have evolved into dances, which allow for lead-sharing whereas Bal, in general, has not. I am not trying to argue that one is better than the other, only that they are different. Cultural constraints aside, the same general physical processes are at work during leading and following in all of these dances. In future posts, I will attempt to explain in detail, the mechanics of pure leading, pure following and lead-sharing.

In this post I have tried to demonstrate that musical, co-creative partner dancing presents a challenging shared control problem. I have argued that systems of movement and connection have evolved, which allow for efficient shared control within a dance partnership, and that this is achieved through mutual predictability between partners. Finally, I have argued that control can be shared in different ways through different systems of leading and following.

In coming posts, I will further explain the notion predictability in movement and give it a clear physical definition. I will then attempt the explain the system of individual movement, which I believe good dancers use to make their motion predictable to their partners, to facilitate good connection.

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Painting jazz

Let's carry on with the definition of musicality from the last post:

Musicality is achieved when a dance looks and/or feels like the music sounds.

As discussed, humans may have evolved an in-built system for associating sounds, shapes and movements. This system is shared across the population so people usually agree on what is musical dancing and what isn't.

I think there's something else to add here: The correspondence between sounds and dance shapes/movements is not one-to-one.

I don't believe that for any given sound, there is one and only one dance movement, which corresponds to the sound better than all other possible movements. There is always some fuzziness, an array of options, all of which will fulfill the inbuilt human assesment criteria for musicality. At least, I have no idea how one could quantify one-to-one correspondences if they did exist. It may even be impossible, if, say, the neural mechanism for these associations makes them based only on coarse properties of the motion and is incapable of selecting between finer details. For example, maybe a quick blast on a trumpet corresponds to a quick movement in some part of a dancer's body, but exactly which part moves might not matter; so long as it's fast, any movement might look equally musical.

Consensus and individuality

I think this is good news because it leaves room for individuality in musical interpretation. Everybody - and every body - is different, each with it's own particular physical constants and predispositions. Similarly, each person's experience with music throughout their lives will have shaped how they hear and interpret music. I believe that the first step for each dancer in finding her own style is to focus on her own natural process for hearing music, extracting its various features and translating them into body movements, which feel natural and musical. In my classes I teach exercises to facilitate this. My experience in these workshops is that ten different dancers will come up with ten different ways to dance one sound but they will usually all look musical. My favourite part of teaching this material is looking around the room and seeing the joy that people get from appreciating the diversity in each other's musical interpretation while also feeling connected through broad agreement. I sometimes get the impression that people feel like they've just discovered that they can speak to each other in a language they never knew existed. For reasons outlined in the previous post, this may in a sense be literally true.

With this is mind, I would like to discuss something. I think there's a mismatch between how most dance teaching is done and the goal that most dancers are aiming for (consciously or unconsciously). I've taken hundreds of dance classes over the years, maybe more than a thousand. And from all those, I think I have enough fingers to count the classes that weren't based on routines of moves. Moves themselves are really just small routines of movements, and moves are linked together to make larger routines. So, from here on, by 'routine' or 'move' I will refer generally to pre-defined patterns - programs - of movement. Of course, good teachers also emphasise the importance of technique and musicality. So it is natural to ask, does learning routines help to develop a dancer's technique and musicality? Are we doing the best job we can do as teachers by focusing on moves?

Shapes and tools

I would like to make a visual analogy here. Every move is like a pre-made, cut-out image. It hangs together in and of itself but it has no background, no context. Imagine now, that like a happy little kid, you are sat down at a table with a long strip of blank paper, a few dozen pre-cut images and some glue. An inspiring piece of jazz music is played to you and you are asked to visually represent your experience of the music by gluing the shapes onto the paper strip in sequence. Your options are only as many as the various permutations of the shapes at your disposal. Rearranging moves in never going to fully represent the beautiful complexity of a person's musical experience.

The dancer would be more empowered if, instead of being given ever more precut images in each class, she were taught how to paint. That is, given a few simple tools - the most basic elements of movement - and then taught the mechanical rules for using those tools to create his/her own original images, extended, flowing and continuous, without breaks or joins, created from moment to moment, directly inspired by the music.

Of course, in the early stages of learning, precut images are useful and are perhaps the best that the learning artist can hope to achieve with the paintbrush while mastering its flow (this is analogous to dancing through a pre-defined move using genuine lead/follow connection and efficient movement). But the goal is to leave all this behind once painting is comfortable. Painting jazz well can only be done spontaneously, improvisationally, from moment to moment, without knowing exactly what the next moment will bring.

In coming posts, I will attempt a course in jazz painting. It will begin with an introduction to the physical principles of good dance moment and proceed to the principles of functional connection between dancer partners. That is, mechanical principles that allow for flowing co-creation of musical dancing. For anyone who's ever struggled with the essence of what the best dancers do when they move and connect, things are, I hope, about to get interesting.

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What is musicality?

Let's try this on as a simple, working definition: A dance is musical when it looks and feels like the music sounds. But how can a look or a feeling be like a sound? I don't have a complete answer to this and, as far as I know, no one else does yet either. But let's discuss some clues.

Sights are sounds: Synesthesia

There is a fascinating phenomenon called synesthesia, which is well studied in perceptual psychology. Synesthesia is a cross-over between senses (sight, hearing, taste...), in which particular experiences from one sense are accompanied by experiences from another sense. For example, a synesthete (a person with synesthesia) may see the colour red when hearing a middle C. An E might be green, a D blue, and so on. Synthesesia comes in all shapes and sizes and sometimes produces strange effects within a single sense; a synesthete friend of mine once told me that she always sees particular letters and numbers in particular colours, regardless of the colour of the text she's looking at (though she's also able to see that colour too; she's conscious of both at once). So, the number 1, for example, is always experienced as yellow, even if the font colour is black. A famous example is an incident in which an accomplished composer/musician visited a tailor and ordered 'a suit in the key of C major'.

Last I read about the subject -- some years ago now -- the prevailing brain science explanation for synesthesia was that neurons in the parts of the brain that deal with different senses would establish connections with each other, which don't exist in most people's brains. These connections would allow the neurons to 'talk' to each other, producing effects that most people don't experience. As it happens, all these regions are located nearby to each other (the whole cluster is called the sensory cortex) in an area at the top of your head, about half way along, called the parietal lobe. This proximity means it's easy for connections to form between visual and auditory neurons, for example. When particular visual neurons fire they might cause connected auditory neurons to fire, and this causes an auditory experience to accompany the visual experience.

Synesthesia is a clear demonstration of natural overlaps between experiences in different senses but it doesn't happen to everyone; it is a 'disorder' affecting a small minority. On the other hand, musicality in dancing seems to be recognisable to everyone. How can we account for this?

Musicality as a quirk of language evolution

Language is among the most intensely studied fields in psychology. It has been argued that humans, uniquely among animals, have an innate capacity for complex language with properties like grammar (Read Stephen Pinker or Noam Chomsky if you want to look into this). It is thought that there are universal laws underlying the grammatical structures in different languages (that is, universal rules about how the specific rules arise). By this theory, the most basic laws of language are hereditary, and these are applied as a child learns particular languages provided by his/her environment.

There are various ideas about how this 'language instinct' evolved in humans. Some authors, like Pinker, argue that language was itself an adaptive trait (it helped our ancient ancestors to survive and reproduce by improving their ability to communicate and work together) and evolved through natural selection. Others, like Chomsky, argue that language appeared as a byproduct of other adaptations. Both of these positions -- the former in particular -- are faced with the challenge of explaining the process of language evolution. What primitive communication strategies came before the complex
languages that eventually evolved? As far as I know, there are a number of competing theories about these early communication systems but I'd like to focus one popular one: that gesture -- visual and tactile language -- was one such early strategy, and verbal/auditory language was gradually added to systems of gestural communication before evolving to dominate them. This resulted in the verbal language systems we have today, where talking/listening is primary and gesture plays a lesser but important part.

By now you might be wondering, what does all this have to do with musicality in dance? Current theories in the psychology of music (see for example, Daniel Levitin's book, 'This is your brain on music') hold that humans' unique capacity for music production and appreciation are a by-product of our unique, evolved capacity for language. Music and language share many fundamental features. Both exploit tone, rhythm, pitch, pause, etc. It can even be shown that the structures in music obey grammatical laws, partly innate and partly culturally defined, just like in language (see Levitin's book).

Echoes of early language evolution can still be seen in the way that people communicate today. Gesture is still a natural part of verbal communication. It might be tempting to write this off as coincidence but there is compelling evidence for a deep, innate capacity for association between visual shapes and sounds. In 1929, the German-American psychologist, Wolfgang Koehler did an experiment in which participants were shown the following two shapes,


and asked which assignment of the two names 'Bouba' and 'Kiki' seemed most natural to them, based only on the sounds of the names and the appearance of the shapes. There was 98% agreement that the shape on the left is the Kiki and the one on the right, the Bouba. 98%! The explanation for this result remains controversial but prevailing theories are based on the above-explained connection between shape and sound, that evolved for communication purposes.

Given that current theories about music psychology trace the roots of music to language evolution, it seems reasonable that the echoes of early language evolution should also be seen in how people interpret and communicate music. We might expect that there should be natural, innate associations between musical sounds and gestures, the latter being made up of shapes and movements. And, importantly, those associations should be shared throughout the population. It is not hard to see how a natural theory of dance musicality emerges from these ideas. Anyone who has ever been to a dance contest and listened to the cheering will know that the crowd tends to agree when the competitors do something particularly musical! This recognition applies not just to momentary shapes but also to whole trajectories of dance. A sequence of tone-matching shapes, strung together through movements that match the musical dynamics and end in a visual full-stop coinciding with a 'break' in the music seem to exemplify innate associations between sounds, shapes, motions, and overall grammatical structure.

This is musicality; a delicious remnant of our evolutionary past.

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Stating the problem: What the heck is 'swing dancing' anyway?

A favourite quotation of mine comes from the jazz critic, Garry Giddins who features in Ken Burns' 'Jazz' documentary series:

"[Jazz] is the ultimate in rugged individualism. It's going out there on that stage and saying, 'It doesn't matter how anybody else did it. This is the way that I'm going to do it.'"

And another, from the great Duke Ellington:

"Put it this way. Jazz is a good barometer of freedom... In its beginnings, the United States of America spawned certain ideals of freedom and independence through which, eventually, jazz was evolved, and the music is so free that many people say it is the only unhampered, unhindered expression of complete freedom yet produced in the country."

The great irony of jazz is that its central tradition is innovation. The greatest jazz musicians and dancers, past and present, rose to fame not by doing what had been done before but by doing something new, their own way, stretching the frame provided by history. I'm not claiming that any old thing qualifies as jazz, provided it's different. I'm claiming that good jazz - both music and dance - is about putting a few new brushstrokes on the giant fresco, which has grown at the hands of many before you, rather than just going over the same old strokes again. I am no jazz connoisseur but I think there might be something in this idea as a guiding principle for getting to the heart of good jazz dancing. In my experience the most common definitions that people seem to have for 'swing dancing' are something like the following three:

1) History: 'Swing dancing' is an umbrella term for the various vernacular jazz dances of the original jazz era. The exact dates and dances included tend to be controversial but the general idea is understood. It follows that the highest goal of any modern would-be swing dancer should be to recreate the dancing that was done 'back in the day', tiny snippets of which can be watched in old videos.

2) Moves: This is an extension of 1). Swing dancing consists of a large list of predefined moves and routines, which have either been handed down from the original swing era or have been created since, 'in the spirit' of that era. According to this definition, a dancer's goal should be to learn and remember these patterns, as well as how to mix and connect them in ways which feel natural, look impressive and reflect whatever music is being danced to.

3) Rockstars: Good dancing is whatever is done by the people who win the most competitions and/or get the most teaching gigs. An aspiring dancer's goal should be to emulate the dancing done by those people.

Predictably perhaps, I think these definitions all miss the point because they focus on doing what someone else has already done; they forget the innovation. I think that all three of the above are kind of 'grades in swing school', phases that dancers progress through as they improve. But in order to graduate, a dancer has to move beyond these and find his/her own style.

But what does that mean?

Good dancers do what they do for all kinds of reasons. Sometimes it's about fancy moves or aerials, which are athletically difficult. Sometimes it's about dancing to the level of a partner, deliberately going easy so that a dance can be fun for someone of a lower skill level. Sometimes it's about being silly and not taking things too seriously, or it could be about taking things very seriously and trying to win competitions. The list goes on. But in my experience there's one universal across all these situations: No matter what the circumstances or goals, good dancing will be improved if it's also musical.

So, what is musicality? It seems to be something that is generally understood - everyone knows musical dancing when they see it - but difficult to break down and explain. So then, if this blog is to focus on picking apart in a scientific way the fundamentals of jazz dancing, this seems like a good place to start...

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