Working memory load disrupts motor performance but preserves adaptation during dexterous object manipulation

Dexterous everyday actions such as grasping and lifting objects rely on precise sensorimotor control and are often performed under concurrent cognitive demands. This study examined how cognitive load induced through a verbal working memory task affects sensorimotor integration in anticipatory adaptation during object manipulation. Participants adapted to an asymmetrical mass distribution by generating compensatory moments at object lift onset, with the aim of minimising object roll. Sensorimotor adaptation performance and grip force modulation were assessed under both single-task (motor only) and dual-task (motor plus working memory) conditions. Results showed that cognitive load led to longer reaction times and increased grip forces, indicating cognitive-motor interference consistent with previous literature. Crucially, however, the trajectory of the adaptation to the novel object dynamics remained robust even under high cognitive load. This resilience suggests that the core processes of error-driven, trial-by-trial motor adaptation which hinge on salient, task-relevant visual and haptic feedback, are relatively immune to the disruptive effects of concurrent working memory demands.