Tag Archives: 2003

Newell on motor schema theory

Newell, K. M. (2003). Schema theory (1975): Retrospectives and prospectives. Research Quarterly for Exercise and Sport, 74, 383-388.
A brief commentary is provided on the theoretical assumptions, scholarly impact and continuing influence of the schema theory of motor learning (Schmidt, 1975). The traditional contrasts of schema theory to the coordinative structure or dynamical systems framework are reemphasized, and limitations of the variability of practice experiments noted. A central problem for theories of motor learning is change over time, the basis on which learning is typically defined. Most theories including schema have, however, undervalued the importance of the time-dependent nature of change in deference to the almost exclusive study of the amount of some averaged change in behavioral outcome. The persistent and transitory changes in movement and outcome that are observed in action are reflections of multiple time scales of change in a dynamical system.
Newell provides some historical context for the development of motor schema theory, highlighting its outgrowth from the 1970s concepts of motor planning and closed-loop theory. He sets up an argument that motor schema theory is inadequate to the task of explaining novel action, and that the proposed storage-savings offered by schemata are not necessary given moden conceptions of cognition.
Newell gives us a few notes to anticipate likely objections to a dynamical systems approach–1) complexity and coordination do not require a designer or central planner, 2) one can have a cognition based on representations, without requiring a symbolic architecture–and points out that schema theory offers little to account for where schema come from in the first place.

He argues that research supporting schema theory, which often relies on the observation that performance improves with varied practice (where we have a chance to dance around the target a bit), has historically had both internal validity problems (the effect of variability of practice is confounded with similarity effects), and external validity (limiting practice to a few score trials, and thus ignoring relatively permanent change for temporary effects).

Left unstudied by research in the motor schema are the development of new coordination patterns and issues of contextual interference. We need more research on just what it is we learn in motor learning: “what are the fundamental phenomena that reflect persistent and transitory change and need to be handled in a motor learning theory?” (That is, we need to describe the phenomenon before we can explain it.)

My questions
I found this critique vague. It levied a few charges against schema theory, and stated that dynamical systems theory doesn’t suffer from some limitations that others have apparently accused it of, but gives us few details about what dynamical systems has to offer.
Q1) p. 387 “one can accommodate the qualitative types of change in movement and action by a small group of principles from dynamical systems theory” What are these principles?
Q2) p. 387 “schema was and is both metaphorically and in reality more of a static than a dynamic theory of learning.” If motor schema are anything like the Piagetian notion of schema (or, indeed, the Kuhnian paradigms of science the author references), then is “punctuated equilibria” more accurate than “static.”
Q3) p. 385 What are non-symbolic representations like? Just laid-down “recordings” of neural patterns?

Schmidt on motor schema theory

Schmidt, R. A. (2003). Motor schema theory after 27 years: Reflections and implications for a new theory. Research Quality for Exercise and Sport, 74, 366-375.

Abstract: The schema theory for discrete motor skill learning (Schmidt, 1975), originally published in 1975, has generated considerable interest and received strong challenges over its lifetime. In this paper, I focus on the findings generated since 1975 that bear on the theory and highlight those that produce difficulties for it and will be motivators for differing theoretical viewpoints in the future. At the same time, I examine other lines of evidence that seem to bolster the original lines of thinking. Finally, I provide some suggestions for a much needed new generation of motor learning theory, pointing out particular features.from the schema theory that could be included and suggesting gaps and omissions that will need additional data and theorizing in future attempts.

What defines motor schema theory?

Generalized motor programs. Feedback from the periphery is too slow to account for many skilled actions, so central planning is necessary. Hence the generalized motor program. To account for variability, these central programs can be modified to take different rate and force values.

Two compartments of memory. We employ recall memory when we select the type of movement that will meet our goals in a given context. We employ recognition memory when we evaluate the movement we actually employed against our stored representation of that movement to assess of error.

The schema concept. Schemata are the relations between movement parameters and the outcomes of those movements. Motor learning, then, becomes the the development of schemata.

Solutions to storage and novelty problems. Schema allow for efficient storage (in the fact of, ostensibly, a limited cognitive warehouse) and for diversity of action.

What aspects of the theory should we keep for future theories?

Motor programs. When we look at EMG recordings of blocked vs. unblocked movement, much of the muscle action is identical. This sequencing does not seem like it could be explained by a dynamical systems approach–the pattern can’t just come together by muscle action, because the muscles aren’t really acting. A central plan seems more likely.

Generalized motor program. We see dissociations between a general movement pattern and at least one type of parameter (rate), supporting the contention that we learn a general program and can scale it. However, the initial contention that force was a second parameter that could simply be linearly scaled to make GMPs generalizable does not seem to be the case (e.g. walking under a load involves scaling of the extensor muscles’ force, but no such scaling is necessary for the flexor muscles).

Limitations of the theory

The motor schema concept does not easily address the motor equivalence problem nor does it address issues of hierarchical control (e.g. in writing where the wrist’s function is different from, and in response to, the elbow’s activity). The theory has had little to say about where generalized motor programs originate. GMPs may arise in situations (random practice with reduction in feedback), that encourage a reconstruction of action. Learning GMPs and learning parameters are dissociated because the latter is slowed under similar conditions.

My questions

Let’s say I notice a disparity between the movement I actually employ, and the motor plan that I selected from my repertoire for the situation.

Q1) If the movement failed to achieve the goal, do I…

  1. assume that the essence of the plan was correct, but that my execution was sloppy? or
  2. assume that I executed an action that fit within the limits of the plan, but that the plan didn’t allow for success in these circumstances.

With a) I might conclude that some parameters of my action were outside the bounds that demarcate a productive action? If so, we might expect the representation to narrow, to constrain future motor activity to a more restricted set of movement parameters.

With b), though, it might be that failure leads us to believe that the parameters in the original motor plan were, in fact, too narrow, and should be broadened to improve the plan’s productivity in the world. So we’d update the motor plan to be less restrictive than before.

Q2) Assuming these are both reasonable responses, how does the cognitive architecture choose in which way to update the schema? (This would seem to be an assimilation/accomodation question.)

Q3) Should we think of this in Bayesian terms, with the system holding on to motor plans that have a good history of surviving tests (unless there’s a preponderance of evidence to the contrary), and more likely to change motor plans with a shorter/poorer track record (even with relatively paltry evidence to the contrary)?