Tuesday, 14 September 2010

Learning a Novel Coordination; Things Get Interesting

Other coordination posts are here.

This will be a brief post to follow on from the last, in which I reviewed the early learning studies of Kelso & Zanone that led to the dynamic pattern hypothesis.
These original studies looked comprehensive and compelling. In 1994, Zanone and Kelso published a book chapter summarising the work so far and laying out the dynamic pattern approach. In it, they made a specific prediction:
...learning rate should vary inversely with the stability of the closest intrinsic attractor to the required pattern.
Zanone & Kelso, 1994, pp 482
In other words, learning a novel coordination closer to 0° should be harder than learning one close to 180°, because the stronger attractor at 0° will interfere more with the learning process.

Two papers tested this hypothesis.

Fontaine et al (1997) compared rates of learning and final performance for learning 45° vs. 135° (equal 'distance' in relative phase space from the two attractors). They also looked to see how this learning process affected the intrinsic dynamics; recall Z&K had observed a loss of stability at 180°.

The results were stark: people found 45° easier°, not harder to learn, and there was only a transient loss of stability at 180°.

Wenderoth et al (2002) then tested learning at distances of 36°, 60° and 90° from the two attractors at 0° and 180°. They again found the exact opposite of the predicted result; learning novel coordinations close to 0° is easier, not harder, than those close to 180°.

Wenderoth et al (2002) then referenced a second literature that had, until now, been running parallel to the movement literature; that of the visual perception of relative phase. This work, from the lab of my PhD advisor Geoff Bingham was premised on the fact that the HKB pattern persisted even when the limbs being coordinated belonged to two different people (Schmidt et al, 1990), and that relative phase might therefore be a perceptible property. This work, which I will review in more detail next time, was showing that visual perception data were also showing all the HKB effects - 0° was identified more reliably, than 180° and the region around it was readily discriminated (i.e. participants could distinguish relative phases close to 0°). 90° was, perceptually, judged to be intrinsically variable. Bingham was suggesting a perceptual basis for the movement phenomena, which actually predicts the results seen by Fontaine et al and Wenderoth et al; the latter explicitly make this connection.

Fontaine, R., Lee, T., & Swinnen, S. (1997). Learning a new bimanual coordination pattern: Reciprocal influences of intrinsic and to-be-learned patterns. Canadian Journal of Experimental Psychology/Revue canadienne de psychologie expérimentale, 51 (1), 1-9 DOI: 10.1037/1196-1961.51.1.1

Schmidt, R. C., Carello, C., & Turvey, M. T. (1990). Phase transitions and critical fluctuations in the visual coordination of rhythmic movements between people. Journal of Experimental Psychology: Human Perception and Performance, 16(2),  227-247. Download

Wenderoth N, Bock O, & Krohn R (2002). Learning a new bimanual coordination pattern is influenced by existing attractors. Motor control, 6 (2), 166-82 PMID: 12122225

Zanone, P.G., & Kelso, J.A.S. (1994). The coordination dynamics of learning: Theoretical structure and experimental agenda. In S.P. Swinnen, H. Heuer, J. Massion, & P. Casaer (Eds.), Interlimb coordination: Neural, dynamical, and cognitive constraints (pp. 461-490). San Diego, CA: Academic Press.

1 comment:

  1. Ouch!

    Let me begin by copping to some of the mistakes you point to. First, yes, Amazeen, Sternad and Turvey was the wrong paper to cite. Nia Amazeen has already (politely) yelled at me about this. The backstory is that I wrote this chapter while sitting in on Turvey's seminar in 2003, and many of the papers discussed in the chapters are from Turvey's reading list. Somewhere in the 5 years between writing the chapter and the page proofs, the wrong citation from that list got cemented into my text. I plead guilty; I plead guilty also to not having gone back to check which article I read while writing this section. Second, I'm not sure what I'm supposed to have missed about Schoner and Kelso, but I don't dispute your superior knowledge of this literature. Third, my claims about Stephen, Dixon and Isenhower were based on discussions with Damian Stephen, rather than the published paper. In fact, I wrote the section of the book before having seen the paper. It is better to view the work in the 2009 paper, and the work that has followed, as you suggest: as stemming from the same sources as HKB model (i.e., synergetics and the dynamics of phase transitions) than as stemming from the HKB itself.

    OK, I suck. I wish I could say there weren’t other mistakes in the book, but there are.

    (I also would have written some of this differently had I read your blog posts on coordination dynamics beforehand.)

    There are some things I do stand by, though. For one, Schmidt et al has been understood by most everyone as genuinely social coupling. There is a cottage industry on social coordination dynamics that has grown out of this work, as you know. I think they get it right: interpersonal perceptual coupling just is a variety of social coupling. For another, while I agree that a theory is a better way to have a guide to discovery than a set of flexible models, I think it is a mistake to say, as you seem to be saying, that good science can’t be done without explicit commitment a theory. Look, for example, at the Stephen et al work. As you correctly point out, this work is inspired by the dynamical models of phase transitions. That’s not a psychological theory. The experiments are inspired by the models, as attempts to see if there are more phenomena that they apply to. So, as a matter of empirical fact, lots of successful science is inspired by models, without commitment to any particular theory.

    That said, I do agree that theory is a better guide to discovery than models. It is more flexible, and not only because theories are generally compatible with a wide array of models. This is why the next few chapters are in the book.

    Thanks, again, for spending so much time on the book.