Implicit perceptual learning and the significance of chance comparisons: a response to Jackson

I present a re-analysis of the data from Farrow and Abernethyʹs (2002) study of implicit perceptual training in tennis. I argue that there are several weaknesses and mistakes in the original analysis, which, when rectified, lead to a fundamentally different set of conclusions to those given in the original paper. Specifically, there are significant group differences in anticipatory performance before the intervention that make subsequent between-group comparisons at specific occlusion points problematic. Second, in contrast to what is reported in the original paper, the explicit learning intervention resulted in a significant improvement in performance. In addition, a comparison of the effects of the different interventions indicates that the placebo group demonstrated the largest mean improvement in anticipation for the four occlusion points up to racquet-ball impact. Third, the non-significant change in performance over a 32-day retention period indicates that any improvements in performance were retained, not lost, over this period of time. Following a re-analysis of the original data, I conclude that Farrow and Abernethyʹs study provides no evidence that an implicit perceptual training paradigm improves anticipatory performance more than either an explicit learning paradigm or, indeed, an intervention involving mere observation of tennis matches.