Anticipating the Lateral Direction of Penalty Kicks in Football From PCA-Reduced Point-Light Displays
Résumé
The anticipation of the direction of football penalty kicks was assessed using Point Light Displays (PLDs). To that end, Principal Component Analyses (PCAs) were applied on previously registered penalty kicks. The PCAs provided an accurate description of the kicks: an average of 98.7% of the variance was explained with the first 6 PCA modes. The results of the PCAs were used to create 7 stimulus conditions, showing PLDs of the kicks as seen from the perspective of the goalkeeper. The first condition included all PCA modes and hence used PLDs of the original penalties. The remaining 6 conditions used all PCA modes until Mode 1, 2, 3, 4, 5, or 6, respectively. Participants observed the PLDs until the moment of ball contact and judged the lateral direction of the kicks. The percentages of correct judgments per condition revealed that the information for the anticipation of penalty kicks is contained in relatively few PCA modes. This confirms previous results obtained with tennis ground strokes (Huys, Smeeton, Hodges, Beek, & Williams, 2008), although for tennis ground strokes even fewer PCA modes seemed to be required to achieve accurate anticipation. The relevance of the ecological notion of information for the PCA-motivated body of research is discussed.