Ms Hedgehog is researching the dynamics of flow in the ronda, comparing with traffic and pondering about the importance of song length.
While song length can probably have some influence, I believe other factors are much more significant. And it is kind of hard to perform real experiments, even though she deserves credit for the attempt.
According to Jorge Dispari, the flow on the dance floors of Buenos Aires used to be much better than today. At Canning, for instance, during the peak hours, the circulation almost stops completely. While it is still possible to dance, it is not as enjoyable as when there is good circulation. And if he is to be believed, there was more people on the floor at that time as well, so floors being more crowded is not the reason.
He explained it by two factors:
Dancers today don’t have the necessary skills
Dancers interpreted the music more in the same fashion earlier
While it is impossible for me to compare earlier times in Buenos Aires today, my experience from milongas all over the world largely supports the main idea that navigation skills and interpreting the music in a similar fashion improves the flow on the dancefloor.
Here is why: I know from teaching and observations on practicas and milongas support that ‘too few’ have the ability to dance a) in a straight line b) on the spot c) change between these when necessary. Dancers also observe the need to keep moving and not moving counter to the line of dance. Which I attribute to a lack of skill. If they know how, but choose not to, I attribute it more to musical interpretation. If dancers cannot keep within their own space, they are likely to cause a congestion or at least interrupt the other dancers.
If dancers are generally in agreement that they need to move at certain speed around the dance floor, congestion is less likely. Anyone stopping while the others keep moving easily clogs the entire floor in less than a minute, which is easy to show by experiment (yes I have done this on several occations). When dancers are generally in agreement of which parts in the music are for moving around/walking, and which are for more stationary repertoire like giros (the final variation for instance), the flow improves.
Hmm – a little more work, and we might have the proof here :-). Assume we have enough dancers to achieve a crowded dance floor. (Too much space, and everybody can move wherever they like, and no significant interaction occurs.) Lack of skills imply congestion. Heterogenous musical interpretation implies congestion. Skills and homogenous musical interpretation are necessary, but not sufficient conditions for good flow of the ronda.
Of course, you could show experimentally that the three minute theory is true, at best you could show that it is a necessary condition given sufficiently crowded floor. I do believe it occurs, but I believe it mainly covers the corner case where both conditions above are satisfied, but the floor is extremely crowded and good dance music with songs significantly longer than three minutes being played.
Say we have all three confirmed by experiment, how do we establish their relative importance? One could do a large survey of milongas, estimating the skills of dancers etc and do a regression, I suppose. For me, it is enough to know that the tree minute song limit is pretty much satisfied for all golden age tango music, so it is hard to imagine when it would be significant. I.e actually affecting the flow of the ronda. (If you play other music with longer songs, I belive other factors than song length destroys the ronda flow.)
As to how to improve the skills and musical interpretation, I don’t have the answer. Not allowing unskilled dancers is not exactly how to achieve a milonga with good attendance these days, I’m afraid.
If only it were possible to create a milonga ouside Bs As where you could feel that the entire dance floor was dancing and breathing together, making the old adage true: You have three dance partners in tango: 1) Your partner 2) The music 3) The dance floor.