Is imagery better than reality? Performance in imagined dart throwing

Abstract

We investigated whether deviations from optimal performance are predicted in motor imagery. In Experiment 1, novices and experts imagined and executed dart throws. In imagination, they reported the final position of the dart. Experts performed better than novices in execution and imagination. Distance to the target and bias were smaller in imagination than in execution. In Experiment 2, we dissociated the roles of feedback from proximal and distal action elements for predictions. Three groups of novices estimated the dart's final position in imagination, in execution without visual feedback, or in execution with delayed visual feedback. Estimates did not differ significantly between groups, indicating that (the lack of) feedback did not influence predictions. Deviations from optimal performance were lower in estimated than in actual performance. In conclusion, although predictive mechanisms may be similar in imagination and execution, the full extent of deviation from optimal performance is not predicted.

Keywords: Action consequences; Darts; Expertise; Feedback; Forward models; Motor imagery.

Fig. 1

Framework of internal models. Intended effects are compared with predicted effects in both, motor execution and motor imagery. Additionally in motor execution, actual effects are observed and compared with intended and predicted effects. Comparisons are depicted as a cross in a circle. The mechanisms in grey do not (or to a lesser degree) take place in motor imagery because activation of the effectors is inhibited (adapted and modified from Blakemore et al., 2002).

Fig. 2

Depiction of the final positions of ten darts throws (thin black crosses), demonstrating distance to the bullseye (8.7 cm, black circle), consistency (6.3 cm, grey circle), and bias (7.2 cm, grey bold cross).

Fig. 3

Means and standard errors of distance to the target before (pretest) and after (posttest) execution (EXE) and imagination (IMA) for experts and novices.

Fig. 4

Means and standard errors of distance, consistency, and bias in execution (EXE) and imagination (IMA) for experts and novices.

Fig. 5

Percentage of the absolute difference (|IMA – EXE|/EXE × 100) between imagination (IMA) and execution (EXE) in distance, consistency, and bias, for experts and novices.

Fig. 6

Means and standard errors of strength of representation in execution (EXE) and imagination (IMA) for experts and novices. Proximal action elements include how it feels to perform the throw, the fingers gripping the dart, the arm movement, and the release of the dart. Distal action elements include the dart’s trajectory and its final position.

Fig. 7

Means and standard errors of distance to the bullseye, consistency, and bias based on actual and estimated dart positions in the execution group with delayed feedback (EXE+FB), the execution group without feedback (EXE-FB), and the imagination group (IMA).

Fig. 8

Means and standard errors of the strength of representation in the execution group with delayed feedback (EXE+FB), the execution group without feedback (EXE-FB), and the imagination group (IMA). Kinesthetic/tactile (kin) and visual (vis) representations of proximal action elements include the finger grip, the arm movement, and the release of the dart. Distal action elements include the dart trajectory and the dart hitting the dartboard.