Individual subject response. Referent coordinate, R, reduces (Panel A), apparent
stiffness, C, does not change (Panel B), and the finger force drops (Panel C)
with time. The dashed line in Panel A shows the actual location of the
fingertip. Panel D depicts the variability in the {R; C} space. Three hyperbolae
correspond to the average force over three time bins, depicted in Panel C as
dashed lines