Richard W. Pew

The speed-accuracy operating characteristic

Abstract An analysis of the relationship between speed and accuracy of performance under a wide variety of task conditions reveals a linear relationship between log odds in favor of a correct response and reaction time. This result is consistent with the conceptual logic of the statistical decision model of choice reaction time and suggests the definition of a speed-accuracy operating characteristic analagous to the receiver operating characteristic in signal detection.

Levels of analysis in motor control

Abstract The analysis of skilled performance must proceed at many levels. As illustrated in the two experiments presented here, what we observe in human skilled behavior is the rich intermingling of these various levels of control as a function of the task demands, the state of learning of the subject and the constraints imposed on the task and the subject by the environment. While we should be interested in the neurophysiological correlates of such behavior we still have a long way to go even to understand what to expect in terms of the behavior itself. The job of the researcher is different depending on the level of analysis at which he is interested, but a general theory of skill acquisition will only result from consideration of the ramifications of a multi-level process-oriented description of skilled performance.

Toward a process-oriented theory of human skilled performance.

Skilled perceptual-motor performance should be approached from a point of view of the processing operations performed by S in a skilled task. This perspective is emphasized in recent attempts to develop analytic or computer-simulation models of tracking tasks. These models are illustrated, and it is argued that a model that has a discrete correction compensatory path and a continuously programmed pursuit path may form one starting point for a more general representation. This representation needs to incorporate as yet undefined processing and storage units to handle coherence prediction, memorized movement patterns, and compensation for external system dynamics.

The importance of age effects on performance in the assessment of clinical trials

Abstract Forty young adult normal subjects, 10 Parkinsons disease patients and their 10 matched normal subjects, and 10 multiple sclerosis patients and their 10 matched normal subjects were evaluated in the Quantitative Examination of Neurological Function to determine age effects and the importance of selecting closely matched normal control groups for assessing the performance of patients. Where there are significant differences among the three normal subject groups, it is the oldest normal subject group that differs from the two younger subject groups. Significant decreases in performance with increasing age were found for the steadiness tests performed in the supported position, the sensation tests, two or five tests in the Neuro-Psychological Examination and tests requiring fine skilled movements primarily with the dominant hand. It was found that older subjects made fewer errors in coordinated tasks. A normalization technique, expressing performance as a percentage of normal function, was introduced. A method was developed to provide quantitative and meaningful indices of neurological function. The measure is obtained by averaging the percentage of normal function scores over several tests that belong to a primary category of neurological function. Young adult normal subjects do not perform significantly better than normal subjects in the age range of multiple sclerosis patients; however, young adult normal subjects do perform significantly better than normal subjects in the age range of Parkinsons disease patients, especially on tasks requiring fine skilled movements of the dominant hand and coordinated activities of the lower extremities. These results indicate that the performance of multiple sclerosis patients can be expressed as a percentage of the function of either age-matched normal controls or young adult normal controls. However, the performance of Parkinsons disease patients should be expressed only as a percentage of the function of age-matched normal controls.

Quantitative evaluation of neuropharmacological trials.

The clinicians ability to classify a patients neurophysiological deficits into such categories as mild, moderate, and severe does not readily allow the detection of small but significant changes in function over time. Clinical neurologists, for example, are discovering that the standard neurological examination is not sufficient to critically evaluate new drugs and surgical techniques that purport to improve the performance of patients in the activities of daily life.1 As a result, the quantitative evaluation of the functional capacity of patients with