Jean‐Louis Thonnard

The paper shows that gravity affects the perception of tangential forces during manual tasks, creating a haptic illusion where downward forces are overestimated compared to upward forces.

The paper develops a device to measure fingerpad skin deformations during active object manipulation and shows that grip force influences skin strains and strain rates.

The paper shows humans adapt grip force to friction changes within 370ms by using skin deformation patterns detected by mechanoreceptive afferents.

The paper shows that humans adapt to unexpected force field disturbances during reaching movements, with within-movement feedback corrections improving and inducing after-effects, suggesting a fast time-scale of motor learning.

The paper shows participants adjust grip force based on expected gravity changes, using a combination of anticipation, safety factors, and feedback mechanisms.