The normal force (Fn, panels A and B), tangential force (Ft, panels C and D), and total moment of force (MTOT, panels E and F) exerted on the handle for the narrow (panels A, C, and E) and wide (panels B, D, and F) handle widths. The data averaged across all subjects with standard error bars are shown. White bars indicate forces and moments of force produced by the virtual finger (VF) while grey bars indicate forces and moments of force produced by the opposing effector (OE). The data averaged across all subjects with standard error bars are shown. The abscissa shows finger configurations; T – thumb, I – index finger, Obj – inanimate object, subscripts R and L refer to the right and left hands, subscript E refers to the experimenter.