Abstract
Perceptual feedback is fundamental to the control of skilled action, and perceptual feedback includes more than vision. Here we provide evidence that athletes have more precise proprioceptive feedback than non-athletes when throwing to a visual target. This was investigated by having 71 participants (34 were varsity athletes) make 100 blindfolded beanbag tosses to a visual target 4 m distant. Prior to each throw participants viewed the target and then pulled down the blindfold. After each throw, participants made judgments of their proprioceptively-perceived performance on that throw (two forced choice judgments: left vs. right and short vs. long) prior to lifting the blindfold to see the actual outcome. This late visual feedback was to reduce drift in the calibration of throwing. A payment reward scheme emphasized throwing accuracy, and gave additional points for report accuracy – but only when the throw was near the target to avoid intentional misthrowing. In a control experiment (N=18), participants simply threw the beanbag with full vision throughout. Throwing performance was reliably more precise (lower SD) with full visual feedback for both athletes and non-athletes. Throwing performance was also better for athletes than for non-athletes in both sighted and blindfolded conditions, though sighted non-athletes out-performed blindfolded athletes. Most importantly, proprioceptive/kinesthetic JNDs computed for both aim and distance were highly correlated with blindfolded performance in both athletes and in non-athletes. Athletes showed greater perceptual precision than non-athletes overall. This differential proprioceptive/kinesthetic sensitivity is sufficient to account for quantitative differences in skilled performance both when blindfolded and when full visual feedback was present. Rather than speaking of visuo-motor tuning, we may think of skilled throwing performance as involving coordination of kinesthetic feedback (observed discrepancies between intended/predicted and produced action) and visual feedback about the outcome of that action.
Meeting abstract presented at VSS 2013