Context-dependence of Aimed Arm Movements: A Transitory or A Stable Phenomenon?

Abstract

Previous work documented that grasping movements in a typical laboratory context differ widely from those in a more natural context. We evaluate whether this context-dependence changes with experience.

Data from 48 subjects (24 female; 24.9 ± 2.7 years of age) were (re)analyzed. They had participated in experimental blocks with externally triggered, purposeless and repetitive movements (context L, laboratory-like), and a block with self-initiated, ecologically valid movements embedded in a complex task (context E, everyday-like). Mechanical constraints on grasping were identical in both blocks.

A global metric, representing context-dependence across multiple kinematic parameters, did not change appreciably across the 20 trials of a block. Furthermore, the metric was not affected by prior participation in the other block.

We conclude that context-dependence of grasping is robust, i.e., it shows little influence of prior experience. This opens the avenue for within-subject designs on context-dependence, e.g., for clinical investigations.

Keywords: Motor control, Prehension, Context-dependence, Serial order, Attunement