ABSTRACT Everyday interactions with objects depend on keeping the grasped item in static equilibrium by effectively distributing the contact forces from the fingertips. The mechanical advantage hypothesis (MAH) proposes that the central nervous system (CNS) optimises the distribution of grasping forces by favouring fingers with longer moment arms. While existing research has established that the applicability of MAH is influenced by biomechanical constraints, it remains unclear whether cognitive load, a distinct dimension of task difficulty, can similarly induce this force-sharing strategy. To investigate this, we examined whether increased cognitive demands imposed through a concurrent dual-task paradigm during a multi-finger grasp-lift task at a moderate mechanical load (0.250 kg) would trigger force distribution patterns that utilise mechanical advantage. Our results showed participants completed the task successfully and that task stability manifested through steady virtual finger grip forces and net handle tilt. However, contrary to our hypothesis, increased cognitive load did not result in a disproportionate rise in the normal force exerted by the little finger compared to the ring finger. This finding suggests that the employment of optimisation strategies like mechanical advantage may be predominantly sensitive to biomechanical rather than cognitive constraints.
Dutta et al. (2026) studied this question.