Pamela Villavicencio¹, Jonathan S. Tsay², Cristina de la Malla¹; ¹Universitat de Barcelona, ²Carnegie Mellon University

Motor adaptation relies on both explicit and implicit learning processes. However, how these processes are impacted by the training context is not well understood. To address this, we compared two groups of participants (N=40) that adapted to a visuomotor gain perturbation (0.7) in a centre-out reaching task with different training target configurations. The Angular Group trained with targets of equal amplitude but in different directions, while the Extent Group trained with targets of different amplitudes in a single direction. Both groups shared a common training target. After training with continuous perturbed feedback, we assessed generalization by interleaving no feedback probe trials in which participants reached either to novel targets or to the shared target. In the final phase, we measured aftereffects by removing visual feedback entirely and having participants reach to the same target positions tested during the generalization phase. During the training and generalization phase, motor performance reflected both implicit and explicit learning processes. In the aftereffects phase, participants were instructed to forgo any explicit strategies, ensuring that performance indexed only implicit adaptation. Our primary dependent variable was the change in movement amplitude across these phases. We found that both groups learned to compensate for the visuomotor perturbation rapidly and fully, showing no measurable differences. However, the groups differed strikingly in how they learned: At the common training target, the Extent Group showed smaller aftereffects than the Angular Group, indicating a stronger reliance on explicit strategies. At a novel amplitude in the trained direction, the Extent group outperformed the Angular group through the use of a successful explicit strategy. At novel angular targets, the Angular group outperformed the Extent group, relying on greater implicit adaptation. Together, these findings underscore the role of training context in shaping how we learn.

Acknowledgements: CM was supported by PID2023-150883NB-I00, CNS2022-135808, MCIN/AEI/10.13039/501100011033 and the European Union NextGeneration EU/PRTR . PV by grant PRE2021-097890, MICIU/AEI/10.13039/501100011033 and FSE+. JST by Carnegie Mellon University Department of Psychology Seed Funding.