Whiting, H. T. A. (John), Stefan Vogt, and Beatrix Vereijken. 1992. "Human Skill and Motor Control: Some Aspects of the Motor Control-Motor Learning Relation," in Approaches to the Study of Motor Control and Learning, edited by J. J. Summers, 81-111. Amsterdam, The Netherlands: Elsevier Science Publishers.

Authors review research on motor control and learning, two related but distinct areas of inquiry that have largely ignored each other. Each of these two research areas is in turn analyzed according to another opposition, that between computational and ecological psychology models (aka "prescriptive" vs. "emergent" theories" (105) or, in the terminology of Tooby & Cosmides 1992, between general-purpose and content-specific mechanisms). They cite one source (Pew & Rosenbaum 1988) as taking the middleground, as Narmour does in music, by insisting that top-down and bottom-up theories are complementary rather than competing. Some terminology: "coordination" denotes the creation of reference frame in which degrees of freedom of movement are reduced to the minimum necessary; "control" refers to the manipulation of these remaining degrees of freedom; and "skill" is the ability to achieve optimal values for these remaining parameters. Motor control is understood as the problem of understanding human movement in "the here and now," in solving "an immediate motor problem posed by the environment" (84). Motor control studies have usually investigated "overlearned stabilised motor performance," expert performance in highly controlled environments, while more average performance and longitudinal studies of motor development have been neglected. The computational/ecological split in the motor control literature boils down to problem specifications in mechanical engineering terms (including motor "programs," "schemas," probably also "grammars") vs. analyses of the physics of the environment and of the organism that evolved to cope with it. Authors tilt toward the latter, as centralized motor program models do not describe well varying behavior, nor are they compatible with evidence for the distributed nature of motor control. Motor learning models must deal with two related phenomenon, learning an action and learning to achieve results (my example: visualizing the golf swing vs. visualizing the golf shot). Computational models have mostly looked at how people learn to fine-tune their skills while ignoring the frame problem, i.e. how did a given motor program originate. As an answer to this problem, they hold out some hope for the notion of "templates" or "internal models" that are formed "prior to overt performance." Ecological models include both "action theory" and "natural physics" approaches. In this Gibsonian view, perception and action are taken to be integral to each other. Ecological studies that address learning specifically are few; the focus has been on understanding the dynamics of certain skills, on the assumption that such understanding will furnish an appropriate reference frame for looking at learning. Some have suggested that a person's "exploratory behaviour is highly structured and effective, rather than being random or trial and error" (94) and is informed by perception of the physical dynamics of the problem. The implication for learning, then, is to look at how individuals or teachers structure motor learning problems in order to converge quickly on solutions; authors note a lack of willingness on the part of researchers to profit from the experience of educationists on this point. Two examples of experimental studies from authors' own work show how studies of motor control can be informed by motor learning and vice versa. The first mentions in passing the lack of evidence for a "Fourier coding analogy," in which "a movement trajectory is internally represented interms of sine wave components" (95). Does this have relevance to Vaughn's time series analysis of lament (1990)?

This review of the literature gives a valuable backdrop against which to place studies of "biogrammars" of musical performance—the assumptions that such a model makes, the problems left to be resolved, perhaps the lack of acknowledgement of emergent properties of human motor behavior. It traces a similar dichotomy that Tooby & Cosmides do between general computational models and content-specific mechanisms produced through evolutionary means. It acknowledges a lack of theorizing of the relationship between observable behavior of the moment (motor control) and the acquisition of these skills over time (motor learning). Authors maintain that motor learning cannot be deduced by comparing the motor control behavior of experts vs. novices, but only begin to address the reverse: how motor control mechanisms may be described by studying motor learning. Where are those longitudinal studies of skill acquisition in individuals? Do studies like Baily's and Blacking's hold some answers? Authors' surprise ending connects motor control studies to "the physical" and motor learning to "the cultural" aspects of "human skill." Is thus revealed a simple nature/nurture assumption underlying their discussion? This seems unnecessary. If anything, it occurred to me while reading this that it is important to be clear about which oppositions are equivalent, which ones are orthogonal, and which ones partially covary. For example, Narmour tends to equate bottom-up processes with nature and top-down with nurture, but this does not admit of the possibility that some bottom-up capabilities must be "learned" (or, perhaps more precisely, developed) and that some "top-down" computational mechanisms may have been adaptations.
Mark DeWitt

These authors explicitly oppose an approach such as the one laid out by Harvey (1985). Schema based approaches, they argue, do not sufficiently explain the process by which an individual gains coordination and control in a task. And, unlike Harvey (1985), Whiting et al provide experimental evidence in an attempt to show how an ecologically based approach can better account for how an individual learns both a simple pattern reproduction task and slalom ski-movements. Additionaly, this paper takes pains to explicate important terms, which I will summarize here. First, they distinguish between three terms relating to stages of skill actuision: coordination, the process of constraining degrees of freedom into a coordinative structure; control, which involves mainpulating the parameters in this structure; and skill, which is assigning values to these parameters. Additionally, the authors distinguish between different approaches to motor control. First, the motor program approach which involves preparation for movement based on an abstract model of performance. This is distinguished from a second computational approach, which involves the use of an internal model which is refined by practice. Harvey's approach essentially combines these two approaches. The third approach, which the authors favor, is termed ecological and involves actively incorporating perception into performance during skill acquisition. Evidence for this final approach stems from exploratory use of the limbs that reflects growing comprehension of the task at hand. The authors describe two experimental studies as support for the ecological approach to skill acquisition. The first investigates transfer of learning in a simple pattern reproduction task. The pattern to be reproduced was a complex signal consisting of two frequencies. The authors varied frequency and phase across patterns. This study found that in this task, transfer of training was not dictated by frequency or phase per se, but on incorporating a pattern of relative timing and amplitude that emerges from the combination of these factors. The second experimental study looked at slalom-ski maneuvers. The strongest evidence for the ecological approach here was adaptation of relative phase betweeen the performer's center of gravity (at the body's midline) and where the performer's feet were located. The pattern of results shows that perforers pass through different stages of performance when acquiring this skill. While the experiments cited here do show that learing coordinative structures may involve active exploration of the task, the degree to which perceptual feedback is necessary during the exercise of these tasks is not established. To be fair, this would be difficult to establish. Additionally, the distinction made between motor programs and computational theories of control does not appear in other work to be as strong a distinction as the authors imply it is here.
Peter Q. Pfordresher

This article points out the distinction between theories of motor control and motor learning. Generally, motor control theories have focused on performance of a learned skill, and separate motor learning theories have focused on the learning of the skill; however there have been exceptions (ex: Schmidt's (1975) motor learning theory). The article also reviews motor programming (Adams, Schmidt) and dynamical system (Kelso, Turvey) explanations of the degrees-of-freedom problem (unfortunately, neither model is described well). Whereas motor programming theories encounter problems when trying to explain how we limit the possible movements to move in an efficient and coordinated manner (df problem), dynamical systems theories are based upon movement constraints that are created by body dynamics. The article also presents experiments in an attempt to show how research on motor learning can provide insight into motor control, and vice versa. The article provides food-for-thought for cognitive ethnomusicologists. Motor learning and motor control are not the same, but can research be done that contributes to both domains. Has the same dichotomy appeared in ethnomusicological work (studying performance vs. acquisition)? Also, hypotheses generated by either the dynamical systems or motor programming theories may be tested by using music (Desain and Honing, 1994; Repp, 1994; Meyer, Palmer, Meyer, 1996).
Rosalee Meyer.