Abstract
Building on Elliott et al.'s (2010) Multiple Processes framework, Tremblay et al. (under review) demonstrated that vision provided only when the limb travelled above 0.8 m/s (VHigh) was as effective as full vision (FV) in controlling endpoint precision (i.e., variable error). Also, these FV and VHigh conditions yielded better endpoint precision than no vision (NV) and vision below 0.8 m/s (VLow) conditions, which did not differ. However, one could argue the use of a single target (i.e., one amplitude) did not promote much use of online feedback and explain why participants only used online vision above 0.8 m/s. In this study, ten participants completed aiming movements towards 9 targets (26, 30 and 34 cm amplitudes) under randomly presented vision conditions (FV, VHigh & VLow with a fixed 0.8 m/s cutoff) as well as two sets of blocked no vision (NV) trials. As one could anticipate, increasing movement amplitude yielded longer movement times and higher peak limb velocities. Also, we largely replicated the results of Tremblay et al. as NV and VLow yielded comparable and worse endpoint precision than FV and VHigh. However, there was no interaction between movement amplitude and vision condition (i.e., VHigh yielded better endpoint precision than VLow for all amplitudes despite using a single velocity cutoff). These results indicate that online visual feedback utilization is confined to a finite portion of the trajectory that may be associated with a range of limb velocities.Acknowledgments: Natural Sciences and Engineering Research Council of Canada (NSERC); Canada Foundation for Innovation (CFI); and Ontario Research Fund (ORF)