Hand-Held Object Force Direction Identification Thresholds at Rest and during Movement.

This study measured the minimum amount of force necessary to identify its direction. The force was produced by a robot and transmitted to a small spherical handle held between the thumb and index finger. We also examined whether this threshold changed during movement. We found that the force threshold was lower when it was possible to move the arm (5 g) than when it was immobile (10 g). [ABSTRACT FROM AUTHOR]