Abstract
An old debate in motor control pertains to the relevance of sensory feedback as a function of practice. Motor planning theories (e.g., Schmidt, 1975; Wolpert, 2007) purport that motor representations are refined with practice, therefore reducing the need for sensory feedback. In contrast, specificity of practice concepts (e.g., Tremblay & Proteau, 1998; Mackrous & Proteau, 2007) purport that sensory feedback remains critical to movement control throughout practice. Such importance of sensory feedback could be mediated by the fact that humans can re-weigh sensory signals to optimize their perceptual judgments (e.g., Ernst & Bülthoff, 2004). The purpose of the current study was to determine if providing accurate visual cues (i.e., with a laser: see Tremblay & Proteau, 1998) in alternation with no-vision trials could alleviate the dependence on visual cues during the performance of an arm flexion movement. Three groups of participants completed 100 acquisition trials towards a single target (i.e., bring the forearm to horizontal) either without vision, with the laser, or alternating between conditions every 10 trials (i.e., mixed). Afterwards, all groups performed 10 transfer trials, without vision. During the acquisition phase, the presence of the laser did yield better endpoint precision than not having vision. Moreover, withdrawing the laser between acquisition and transfer test yielded decreases in endpoint precision. However, no significant differences were found between groups within the transfer test. Although another dataset is currently being collected with three targets instead of one, the results lend further support for the formation of sensory-specific movement representations (cf. motor representations).
