Investigating implicit and explicit contributions to dual visuomotor adaptation


The ability to seamlessly switch between different visuomotor mappings is critical for effective interactions in a dynamic environment. This experiment aimed to establish the implicit (unconscious) and explicit (conscious strategy) contributions to adapting one’s reaches to two small visuomotor mappings simultaneously (DUAL visuomotor adaptation). 59 right-handed participants were divided into two groups: a DUAL adaptation group and a SINGLE adaptation group. The DUAL group trained to reach when cursor feedback was rotated 20° clockwise relative to hand motion when a left target was displayed and 20° counterclockwise relative to hand motion when a right target was displayed. The SINGLE group trained to reach with just one 20° cursor distortion (clockwise or counterclockwise) to both the left and right targets. Results revealed that while both groups adapted their reaches to the distorted cursor feedback, it took the DUAL group significantly more trials for reach adaptation to plateau in comparison to the SINGLE group. Furthermore, the magnitude of final visuomotor adaptation achieved in the DUAL group after 360 training trials was less than the SINGLE group who reached with a clockwise cursor distortion for 180 trials. Similarly, the DUAL group demonstrated significantly less implicit adaptation than the Single group after 180 trials. However, after 360 training trials, both groups demonstrated similar levels of implicit adaptation. There was no evidence of explicit adaptation in either group. Together, these results highlight the role of implicit processes in simultaneously updating two visuomotor mappings to a small cursor distortion.