The role of attention in motor control.

Abstract

Research on the focus of attention (FOA) in motor control has found a consistent advantage for focusing externally (on the effects of one's actions) compared to focusing internally (on one's body mechanics). However, most of this work has concentrated on movement outcomes, leaving open the question of how external attention changes the movement itself. Somewhat paradoxically, recent research has found that external attention also increases trial-by-trial movement variability. To explain these findings, we propose a theory of attention in motor control, grounded in optimal control theory, wherein variability is minimized along attended aspects of the movement. Internal attention thus reduces variability in individual bodily dimensions (positions and velocities of effectors), whereas external attention minimizes variability in the task outcome. Because the goal of a task defines a dimension in the movement space that is generally oblique to bodily dimensions, external attention should increase correlations among bodily dimensions while allowing their individual variances to grow. The current experiment tests these predictions in a dart-throwing task. External FOA led to more accurate performance and increased variability in the motion of the throwing arm, concomitant with stronger correlations among bodily dimensions (shoulder, elbow, and wrist positions and velocities) in a manner consistent with the task kinematics. These findings indicate a shift in the control policy of the motor system, consistent with the proposed theory. These results suggest an important role of attention as a control parameter in the regulation of the motor system, and more broadly illustrate the importance of cognitive mechanisms in motor behavior.

Neuromechanical synergies in single-leg landing reveal changes in movement control

“…Given the outlined descriptions of movement coordination and synergies, PCA can provide interpretations in line with concepts from motor control (Latash, 2010;Li, 2006;Lohse et al, 2013;Scholz & Schoner, 1999), providing a multivariate time series measure of movement variability. Collectively, PCA has been applied to datasets from kinematic, kinetic, and EMG sources, demonstrating utility among a number of tasks (Daffertshofer et al, 2004;Kipp, Redden, Sabick, & Harris, 2012;Kipp et al, 2014;Li, 2006;Richter et al, 2014).…”

“…During movement execution, the available biomechanical degrees of freedom (DOF) exceed those required to successfully perform a task (Bernstein, 1967;Davids, Glazier, Araujo, & Bartlett, 2003). Movement coordination is therefore simplified through dimension reduction (Latash, 2010;Lohse, Jones, Healy, & Sherwood, 2013;Turvey, 1990).…”

Optimizing performance through intrinsic motivation and attention for learning: The OPTIMAL theory of motor learning

“…For example, in skilled dart players it was observed that smaller release angles were compensated by higher velocities of the dart, and vice versa (Loosch, 1995;Wulf & Prinz, 2001). Lohse and colleagues (Lohse, Jones, Healy, & Sherwood, 2014;Lohse, Sherwood, & Healy, 2010) demonstrated that an external focus also leads to greater functional variability than an internal focus.…”

“…Indeed, a recent study by Russell, Porter, and Campbell (2014) showed nicely that an external focus on the primary task (dart throwing) was necessary to enhance performance, whereas an external focus on a simultaneously performed secondary task-which should have directed attention away from the self-was not able to enhance performance (similar to internal foci on either task). The consequence of focusing on the intended effect is a coordination pattern that resembles one that is typically seen at a more advanced skill level-with a more efficient recruitment of motor units, fewer co-contraction of agonists and antagonists (Lohse & Sherwood, 2012), greater force output (Marchant, Greig, & Scott, 2009), a "freeing" of the body's degrees of freedom (Wulf & Dufek, 2009;Wulf, 2013), increased functional variability (Lohse et al, 2014;Wulf & Prinz, 2001), and generally increased movement accuracy. How exactly the motor system accomplishes this is perhaps one of most intriguing questions.…”

Children's learning of tennis skills is facilitated by external focus instructions

“…An external focus facilitates automaticity as evidenced by reduced attentional demands (Kal, van der Kamp, & Houdijk, 2013;Wulf, McNevin, & Shea, 2001), high-frequency movement corrections indicating greater involvement of reflexes (e.g., McNevin, Shea, & Wulf, 2003), increased functional variability (Lohse, Jones, Healy, & Sherwood, 2013), and greater movement fluidity (Kal et al, 2013). As a result, an external focus speeds the learning process relative to an internal focus which tends to interfere with automatic processes (Wulf et al, 2001).…”