Individual subject response. The referent coordinate, R, (Panel A), apparent
stiffness, C, decreases (Panel B), and the finger force drop (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