Chapter 2. Prehension

52 THE PHASES OF PREHENSION
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0 200 400 600 800
DURATION (ms)
Figure 3.2 Wrist velocity and aperture profiles for grasping as a
function of distances and object size. Top row: The subject
reaches out to grasp an object of constant size at three different
distances away. On the left, the velocity profile shows a
systematic increase with distance. On the right, no difference is
seen in the aperture between the thumb and index finger. Lower
row: The subject reaches to grasp two different width objects with
the left and right hands, in a bimanual task to remove a plug from
a bottle. On the left, no difference is seen in the velocity profiles.
On the right, a difference is observed in maximum size of the
apertures (from Jeannerod, 1984; adapted with permission).