Fatiguing verbal working memory to reduce explicit hypothesis testing during skill acquisition: A new implicit motor learning paradigm?

Abstract

How we learn novel motor skills is crucial for motor performance. Motor skills learned through implicit processes have been shown to have higher neural efficiency, lower likelihood of interference from conscious control during motor output, and more stable performance under pressure, stress, fatigue and multitasking situations (Maxwell, Masters & Eves, 2000; Steenbergen, Van Der Kamp, Verneau, Jongbloed-Pereboom & Masters, 2010; Zhu, Yeung, Poolton, Lee, Leung & Masters, 2015). These performance benefits are sought after in both clinical and sporting domains, and make implicit motor learning a viable alternative to explicit forms of learning. However, current implicit motor learning paradigms have encountered limitations that hinder their practical application (Lam, Maxwell & Masters, 2009; Zhu et al., 2015); therefore, new implicit motor learning paradigms need to be created. This thesis investigated whether cognitive fatigue can be used to encourage novices to perform a novel motor task in an implicit manner. We hypothesized that inducing cognitive fatigue in people would suppress verbal working memory activity, thereby minimising hypothesis testing about the task to be performed and causing implicit motor learning. The research was conducted on thirty-three healthy adults (women=19, men=14; mean age= 23.3±5.5) who reported limited golf experience. All participants were randomly allocated to one of two treatment conditions: control (non-fatigued) or experimental (fatigued). We analysed the differences in verbal working memory performance, motor skill performance and hypothesis testing measures between the two groups. Our results showed that participants in the experimental condition reported a significant increase in subjective feelings of fatigue following the intervention; however, this was not reflected by a decrease in working memory activity. The results also illustrated no significant differences in motor performance or hypothesis testing between the two groups. Overall, the cognitive fatigue task was shown to successfully alter self-reported levels of fatigue (VAS-f), although we speculate that the fatigue levels produced by the intervention were not sufficient to suppress working memory activity during performance of a novel motor task.