Abstract
In this experiment, post-trial knowledge of results (KR) was used to promote explicitly guided, re-adaptation of an implicitly acquired adaptation. There is debate about the independence of implicit and explicit learning processes during adaptation. In a key study, implicit learning based on error in expected sensory consequences was found to guide learning independent of "correct" strategic, explicit processes (Mazzoni & Krakauer, 2006). If these processes are independent later explicit re-adaptation should not influence what has been implicitly acquired (evidenced by unchanged after-effects in a normal environment). Fifteen participants gradually adapted targeted reaching movements to a 30º CW visual rotation (with cursor trajectory (CT) feedback of the first half of each trial). After implicit adaptation and tests of after-effects, participants practiced with correct or incorrect (+/-15º) KR about the accuracy of the CT's endpoint. Both incorrect KR groups showed high variable error relative to the correct group, indicative of strategic adjustments to reduce endpoint error. Only participants in the +15º error group showed re-adaptation based on KR. Importantly, these explicitly-induced changes were manifest as larger after-effects (~7º increase) following exposure to erroneous KR than before. This suggests an interdependency of explicit and implicit processes whereby the internal model for reaching can be updated by explicit processes, resulting in augmented after-effects.Acknowledgments: The final author would like to acknowledge funding from the Natural Sciences and Engineering Research Council of Canada (NSERC).