Reporting bias, not external focus

A robust Bayesian meta-analysis and systematic review of the attentional focus literature

Abstract

Evidence has ostensibly been accumulating over the past two decades suggesting that an external focus on the intended movement effect (e.g., on the golf club during a swing) is superior to an internal focus on body movements (e.g., on your arms during a swing) for skill acquisition. Seven previous meta-studies have all reported evidence of external focus superiority. The most comprehensive of these concluded an external focus enhances motor skill retention, transfer, and performance, leads to reduced eletromyographic activity during performance, and that more distal external foci are superior to proximal external foci for performance. Here, we re-analyzed these data using robust Bayesian meta-analyses that included several plausible models of publication bias. We found moderate to strong evidence of publication bias for all analyses. After correcting for publication bias, estimated mean effects were negligible: g = 0.01 (performance), g = 0.15 (retention), g = 0.09 (transfer), g = 0.06 (electromyography), and g = -0.01 (distance effect). Bayes factors indicated data favored the null for each analysis, ranging from BF₀₁ = 1.3 (retention) to 5.75 (performance). We found clear evidence of heterogeneity in each analysis, suggesting the impact of attentional focus depends on yet unknown contextual factors. Our results contradict the existing consensus that an external focus is always more effective than an internal focus. Instead, focus of attention appears to have a variety of effects that we cannot account for, and on average those effects are small to nil. These results parallel previous metascience suggesting publication bias has obfuscated the motor learning literature.