Richard A. Schmidt’s research while affiliated with University of California, Los Angeles and other places

“Unintended-acceleration” automobile accidents typically begin when the driver first enters the car, starts the engine, and intends to press his/her right foot on the brake while shifting from Park to a drive gear (Drive or Reverse). The driver reports an unintended (uncommanded) full-throttle acceleration, coupled with a loss of braking, until the episode ends in a crash. Pedal misapplications – where the right foot contacts the accelerator instead of the brake that was intended – have been linked to these accidents (Schmidt, 1989, 1993) which, in the 1980s, were thought to occur only at the start of a driving cycle (and/or with the car in Park). But, in 1997, we identified over 200 pedal errors as the cause of accidents reported in the North Carolina database; these crashes occurred during the driving cycle (Schmidt et al., 1997), and/or with the vehicle in a gear other than Park. Our present work provides a more thorough analysis of these North Carolina Police Accident Reports from 1979 to 1995. The vast majority of pedal misapplications (over 92%) (a) occurred during the driving cycle, (b) were generally in “unhurried” conditions, and (c) were categorically separate from those events referred to as unintended-acceleration episodes at start-up. These ideas are explanatory for the recent (2009–2010) surge of unintended-acceleration reports, perhaps even suggesting that all of these crashes are caused by pedal errors, and that none of them are based on some vehicle defect(s).

The present study was designed to examine whether applying principles of motor learning to a commonly used treatment approach for acquired apraxia of speech (AOS) would enhance relearning of speech production skills. In particular, we examined one main principle, random practice, and compared it to blocked practice. Of importance is the fact that many speech treatments utilize blocked practice, but the literature on motor learning clearly shows that blocked practice facilitates acquisition of target behaviours, but not retention and transfer. The latter two are considered true indices of learning. In two subjects with severe AOS, results showed that random practice facilitated retention whereas blocked practice did not. The present study provides preliminary evidence that these principles may have a similar effect on learning of skilled speech motor acts as they do on learning of limb movements. The results reported here are encouraging and provide justification and focus for further investigation.

Recent evidence suggests that massive amounts of practice of the basketball free throw (a "set shot") results in the development of a specific memory representation that is unique to this one shot distance and angle, and that is distinct from set shots taken at locations other than the free throw line. We termed this unique capability an especial skill. In this article, we review the evidence and provide new data regarding the existence of especial skills. These findings are discussed in terms of their implications for motor control theory and in terms of the broader context of specificity versus generality in the learning of motor skills.

Two studies examined speech skill learning in persons with apraxia of speech (AOS). Motor-learning research shows that delaying or reducing the frequency of feedback promotes retention and transfer of skills. By contrast, immediate or frequent feedback promotes temporary performance enhancement but interferes with retention and transfer. These principles were tested in the context of a common treatment for AOS. Two studies (N = 4, N = 2) employed single-subject treatment designs to examine acquisition and retention of speech skills in adults with AOS under different feedback conditions. Reduced-frequency or delayed feedback enhanced learning in 3 participants with AOS. Feedback manipulation was not an influential variable in 3 other cases in which stimulus-complexity effects may have masked treatment effects. These findings demonstrate that individuals with AOS can benefit from structured intervention. They provide qualified support for reduction and delay of feedback, although interaction with other factors such as stimulus complexity or task difficulty needs further exploration. This study adds to the growing body of literature investigating the use of principles of motor learning in treating AOS and provides impetus for consideration of pre-treatment variables that affect outcome in treatment studies.

There has been renewed interest on the part of speech-language pathologists to understand how the motor system learns and determine whether principles of motor learning, derived from studies of nonspeech motor skills, apply to treatment of motor speech disorders. The purpose of this tutorial is to introduce principles that enhance motor learning for nonspeech motor skills and to examine the extent to which these principles apply in treatment of motor speech disorders. This tutorial critically reviews various principles in the context of nonspeech motor learning by reviewing selected literature from the major journals in motor learning. The potential application of these principles to speech motor learning is then discussed by reviewing relevant literature on treatment of speech disorders. Specific attention is paid to how these principles may be incorporated into treatment for motor speech disorders. Evidence from nonspeech motor learning suggests that various principles may interact with each other and differentially affect diverse aspects of movements. Whereas few studies have directly examined these principles in speech motor (re)learning, available evidence suggests that these principles hold promise for treatment of motor speech disorders. Further research is necessary to determine which principles apply to speech motor (re)learning in impaired populations.

The timing of glove movements used by baseball pitchers to catch fast approaching balls (i.e., line drives) was examined in two tests to determine the responses and temporal characteristics of glove movements in high school and college baseball pitchers. Balls were projected toward the head of participants at 34.8 m.s-1 (78 mph) on average in an indoor test and at speeds approaching 58.1 m.s-1 (130 mph) in a field test. Pitchers caught over 80% and 15% of the projected balls in the indoor and field tests, respectively. Analyses of glove responses indicated that all pitchers could track the line drives and produce coordinated glove movements, which were initiated 160 ms (+/-47.8), on average, after the ball was launched. College pitchers made initial glove movements sooner than high school pitchers in the field test (p=0.012). In contrast, average glove velocity for pitchers increased from 1.33 (+/-0.61) to 3.45 (+/-0.86) m.s-1 across the tests, but did not differ between experience levels. Glove movement initiation and speed were unrelated, and pitchers utilized visual information throughout the ball's flight to catch balls that approached at speeds exceeding the estimated speeds in competitive situations.

Differing viewpoints concerning the specificity and generality of motor skill representations in memory were compared by contrasting versions of a skill having either extensive or minimal specific practice. In Experiments 1 and 2, skilled basketball players more accurately performed set shots at the foul line than would be predicted on the basis of the performance at the nearby locations, suggesting considerable specificity at this distance. This effect was replicated even when the lines on the court were obscured (in Experiment 2). However, the effect was absent when jump shots were executed in Experiment 3. The authors argue that massive levels of practice at 1 particular member of a class of actions produce specific effects that allow this skill to stand out from the other members of the class, giving it the status of an especial skill. Various theoretical views are proposed to account for the development of these skills.