Abstract
RATIONALE: Visuomotor learning is a powerful tool to discover invariant aspects of action initiated events. We study such learning by investigating the generalization of a new relationship between throwing direction and projectile trajectory. QUESTION: Adjustments in throwing on a rotating carousel produce a robust recalibration (a shift of 3.1 ± 1.7 (mean ± SD)) in the direction of underhanded throwing (Bruggeman et al, 2003). We hypothesized that such a recalibration would transfer to overhand throwing (Exp.1) and throwing using the left (non-preferred) arm (Exp.2), but would not transfer to pointing (Exp.3). METHODS: Experiments used a pretest-adjustment procedure-posttest design. In the adjustment procedure, participants sat on one side of a rotating carousel and threw sixty beanbags underhanded at a target on the opposite side. In both the pre- and posttest, participants were on stationary ground and either threw beanbags overhanded (Exp.1), or lefthanded (Exp2.), or pointed (Exp.3) at several stationary targets. For each trial they were instructed to look at the target, lower a blindfold and perform their action. RESULTS: Pretest/posttest comparisons revealed that adjustments in underhanded throwing on a counterclockwise rotating carousel transferred to significant shifts in the direction of throwing overhanded (shift= 3.9 ± 2.3 ) and lefthanded (shift= 3.2 ± 2.3 ). No such transfer was found in the direction of pointing (shift= .7 ± 1.4 ). Results for clockwise rotation were somewhat more complex. CONCLUSION: Adjustments in underhanded throwing on the rotating carousel appear to recalibrate the visual motor coordination of a system of hurling actions. REFERENCE: Bruggeman, H., Eid, C. L., Rieser, J. J., & Pick, H. L. (2003). Alteration of the direction of throwing; multiple levels of adaptation. Journal of Vision, 3(9), 678a.
This research was partially supported by NSF IIS-0121044, ITR/SY: Collaborative/RUI Research on the Perceptual Aspects of Locomotion, and by the Center for Cognitive Sciences, University of Minnesota.