William Marshall Land

From action representation to action execution: exploring the links between cognitive and biomechanical levels of motor control

Along with superior performance, research indicates that expertise is associated with a number of mediating cognitive adaptations. To this extent, extensive practice is associated with the development of general and task-specific mental representations, which play an important role in the organization and control of action. Recently, new experimental methods have been developed, which allow for investigating the organization and structure of these representations, along with the functional structure of the movement kinematics. In the current article, we present a new approach for examining the overlap between skill representations and motor output. In doing so, we first present an architecture model, which addresses links between biomechanical and cognitive levels of motor control. Next, we review the state of the art in assessing memory structures underlying complex action. Following we present a new spatio-temporal decomposition method for illuminating the functional structure of movement kinematics, and finally, we apply these methods to investigate the overlap between the structure of motor representations in memory and their corresponding kinematic structures. Our aim is to understand the extent to which the output at a kinematic level is governed by representations at a cognitive level of motor control.

An Outcome- and Process-Oriented Examination of a Golf-Specific Secondary Task Strategy to Prevent Choking Under Pressure

The present study examined a new golf-specific secondary task to prevent choking under pressure during golf putting. The study examined skilled (n = 20) and novice (n = 24) golfers on a putting task under high- and low-pressure, while carrying out either a golf-specific or an irrelevant letter generation secondary task to prevent skill-focused attention. Results revealed that both secondary tasks prevented choking under pressure in skilled golfers, but not in novices. Additionally, skilled participants displayed increased movement variability associated with improved performance during secondary task performance. These findings provide support for the viability of the new secondary task technique.

Perceptual-Cognitive Changes During Motor Learning: The Influence of Mental and Physical Practice on Mental Representation, Gaze Behavior, and Performance of a Complex Action

Despite the wealth of research on differences between experts and novices with respect to their perceptual-cognitive background (e.g., mental representations, gaze behavior), little is known about the change of these perceptual-cognitive components over the course of motor learning. In the present study, changes in one’s mental representation, quiet eye behavior, and outcome performance were examined over the course of skill acquisition as it related to physical and mental practice. Novices (N = 45) were assigned to one of three conditions: physical practice, combined physical plus mental practice, and no practice. Participants in the practice groups trained on a golf putting task over the course of 3 days, either by repeatedly executing the putt, or by both executing and imaging the putt. Findings revealed improvements in putting performance across both practice conditions. Regarding the perceptual-cognitive changes, participants practicing mentally and physically revealed longer quiet eye durations as well as more elaborate representation structures in comparison to the control group, while this was not the case for participants who underwent physical practice only. Thus, in the present study, combined mental and physical practice led to both formation of mental representations in long-term memory and longer quiet eye durations. Interestingly, the length of the quiet eye directly related to the degree of elaborateness of the underlying mental representation, supporting the notion that the quiet eye reflects cognitive processing. This study is the first to show that the quiet eye becomes longer in novices practicing a motor action. Moreover, the findings of the present study suggest that perceptual and cognitive adaptations co-occur over the course of motor learning.

Associative and Dissociative Imagery Effects on Perceived Exertion and Task Duration

The study was designed to examine the effects of associative and dissociative imagery interventions on reported ratings of perceived exertion (RPE) and task-duration across a handgrip-squeezing task. Sixty adults (Mage = 22.19 years) were randomly assigned to three groups: associative imagery, dissociative imagery, and control (non-imagery). Participants were instructed to perform a 30% maximal handgrip-squeezing task until volitional fatigue. During the squeezing task, RPE and attention allocation were measured every 30 seconds. A series of RM MANOVA procedures revealed that (a) RPE increased linearly across all three groups as a function of increased effort output, (b) as compared to control participants, RPE was lower in participants using either associative or dissociative imagery, and (c) as compared to control participants, participants using either imagery remained longer on task. While the effects of imagery use on RPE and task-duration were descriptively evident, not all effects were significant. Future studies must examine imagery applications for tasks that vary in workload intensities. Findings shed light on interventions that can possibly render exercise experience more pleasant and less exertive for the general population.

The Influence of Attentional Focus Instructions and Vision on Jump Height Performance

Purpose: Studies have suggested that the use of visual information may underlie the benefit associated with an external focus of attention. Recent studies exploring this connection have primarily relied on motor tasks that involve manipulation of an object (object projection). The present study examined whether vision influences the effect of attentional focus on the performance of body movements through space (body projection). Method: Participants (N = 24, Mage = 25.0 ± 3.3 years) performed a maximum vertical jump in a room with a 4-m ceiling under full-vision and no-vision conditions. Additionally, participants performed 3 trials under each of 3 attentional conditions, presented in a counterbalanced order: external focus (ExF; “concentrate on the ceiling and try to touch it”), internal focus (InF; “concentrate on your fingers and try to bring them up as high as possible”), and control (Con; no-focus instruction). Results: Results indicated that regardless of visual condition, a statistically significant difference was observed such that participants in the ExF condition (30.93 ± 8.37 cm) jumped significantly higher than participants in both the InF (30.09 ± 8.66 cm, p = .004, d = 0.68) and Con (30.23 ± 8.73 cm, p = .002, d = 0.57) conditions. Furthermore, jump height was overall significantly higher in the full-vision condition compared with the no-vision condition (p = .004, d = 0.47). Importantly, there was no interaction between ExF and vision. Conclusion: The present findings demonstrate the benefit of an ExF on a body projection task and further provide evidence of the independence of ExF and visual information.

Whole-body posture planning in anticipation of a manual prehension task: Prospective and retrospective effects

This study examined the extent to which the anticipation of a manual action task influences whole-body postural planning and orientation. Our participants walked up to a drawer, opened the drawer, then grasped and moved an object in the drawer to another location in the same drawer. The starting placement of the object within the drawer and the final placement of the object in the drawer were varied across trials in either a blocked design (i.e., in trials where the same start and end location were repeated consecutively) or in a mixed fashion. Of primary interest was the posture adopted at the moment of grasping the drawer handle before pulling it out prior to the object manipulation task. Of secondary interest was whether there were sequential effects such that postures adopted in preceding trials influenced postures in subsequent trials. The results indicated that the spatial properties of the forthcoming object manipulation influenced both the postures adopted by the participants and the degree to which the drawer was opened, suggesting a prospective effect. In addition, the adopted postures were more consistent in blocked trials than in mixed trials, suggesting an additional retrospective effect. Overall, our findings suggest that motor planning occurs at the level of the whole body, and reflects both prospective and retrospective influences.

Effects of Physical Practice and Imagery Practice on Bilateral Transfer in Learning a Sequential Tapping Task

Recent research on bilateral transfer suggests that imagery training can facilitate the transfer of motor skill from a trained limb to that of an untrained limb above and beyond that of physical practice. To further explore this effect, the present study examined the influence of practice duration and task difficulty on the extent to which imagery training and physical training influences bilateral transfer of a sequential key pressing task. In experiment 1, participants trained on the key pressing task using their non-dominant arm under one of three conditions (physical practice, imagery practice, and no practice). In a subsequent bilateral transfer test, participants performed the sequential task using their untrained dominant arm in either an original order or mirror-ordered sequence. In experiment 2, the same procedures were followed as in experiment 1 except that participants trained with their dominant arm and performed the bilateral transfer task with their non-dominant arm. Results indicated that with extended practice beyond what has been employed in previous studies, physical practice is more effective at facilitating bilateral transfer compared to training with imagery. Interestingly, significant bilateral transfer was only observed for transfer from the non-dominant to the dominant arm with no differences observed between performing the task in an original or mirror ordered sequence. Overall, these findings suggest that imagery training may benefit bilateral transfer primarily at the initial stages of learning, but with extended training, physical practice leads to larger influences on transfer.

Visual and skill effects on soccer passing performance, kinematics, and outcome estimations

The role of visual information and action representations in executing a motor task was examined from a mental representations approach. High-skill (n = 20) and low-skill (n = 20) soccer players performed a passing task to two targets at distances of 9.14 and 18.29 m, under three visual conditions: normal, occluded, and distorted vision (i.e., +4.0 corrective lenses, a visual acuity of approximately 6/75) without knowledge of results. Following each pass, participants estimated the relative horizontal distance from the target as the ball crossed the target plane. Kinematic data during each pass were also recorded for the shorter distance. Results revealed that performance on the motor task decreased as a function of visual information and task complexity (i.e., distance from target) regardless of skill level. High-skill players performed significantly better than low-skill players on both the actual passing and estimation tasks, at each target distance and visual condition. In addition, kinematic data indicated that high-skill participants were more consistent and had different kinematic movement patterns than low-skill participants. Findings contribute to the understanding of the underlying mechanisms required for successful performance in a self-paced, discrete and closed motor task.

Priming of complex action via movement contingent sensory effects

OBJECTIVES The aim of the present study was to examine whether movement contingent sensory effects could be used to prime and facilitate motor performance on a ball-tossing task. DESIGN The ball-tossing task was performed across two consecutive days, and consisted of an acquisition phase and a test phase. During the acquisition phase, participants (N = 30) practiced an underhanded ball tossing task to a near and far target (N = 360 total, n = 180 each distance). Tosses that landed near the target immediately produced an auditory feedback tone upon landing, with unique tones for both the near and far target. In the test phase, the auditory tones preceded the toss and served as imperative stimuli for the tossing task. METHOD The test phase consisted of three tossing conditions (corresponding, non-corresponding, and control) in which the participants responded to the tones by tossing the ball to either the corresponding or non-corresponding target associated with the tones during learning. RESULTS Findings indicated that both accuracy and consistency of ball tossing improved when the toss was preceded by the corresponding auditory feedback associated with the successful execution of the action during learning. CONCLUSIONS The present study extends previous research by showing that complex actions consisting of multiple degrees of freedom can be primed via movement contingent sensory effects. Furthermore, this study demonstrates that movement-effect priming can impact distal measures of motor performance (e.g., accuracy of tossing), as opposed to the features of movement production (e.g., response selection, initiation, and execution).

Action Effects and Task Knowledge: The Influence of Anticipatory Priming on the Identification of Task-Related Stimuli in Experts.

The purpose of the present study was to examine the extent to which anticipation of an action’s perceptual effect primes identification of task-related stimuli. Specifically, skilled (n = 16) and novice (n = 24) tennis players performed a choice-reaction time (CRT) test in which they identified whether the presented stimulus was a picture of a baseball bat or tennis racket. Following their response, auditory feedback associated with either baseball or tennis was presented. The CRT test was performed in blocks in which participants predictably received the baseball sound or tennis sound irrespective of which stimulus picture was displayed. Results indicated that skilled tennis players responded quicker to tennis stimuli when the response was predictably followed by the tennis auditory effect compared to the baseball auditory effect. These findings imply that, within an individual’s area of expertise, domain-relevant knowledge is primed by anticipation of an action’s perceptual effect, thus allowing the cognitive system to more quickly identify environmental information. This finding provides a more complete picture of the influence that anticipation can have on the cognitive-motor system. No differences existed for novices.