Individual subject response. Referent coordinate, R, reduces (Panel A), apparent
stiffness, C, increases (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