The aim of the present study was to determine
whether and how hand shaping was affected by
the presence of a distractor object adjacent to the tobe-
grasped object. Twenty subjects were requested to
reach towards and grasp a \u2018convex\u2019 or a \u2018concave\u2019 object
in the presence or absence of a distractor object
either of the same or different shape than the target
object. Flexion/extension at the metacarpal-phalangeal
(MCP) and proximal interphalangeal joints of all digits,
and abduction angle between digits were measured
by resistive sensors embedded in a glove. The results
indicate robust interference effects at the level of reach
duration and the extent of fingers\u2019 abduction angles
together with changes at the level of a single joint for
the thumb. No distractor effects on individual fingers\u2019
joints except for the MCP of the middle and little fingers
were found. These findings suggest that the presence
of distractor object affects hand shaping in terms
of fingers\u2019 abduction angles, but not at the level of
\u2018shape dependent\u2019 fingers\u2019 angular excursions. Furthermore,
they support the importance of the thumb
for the guidance of selective reach-to-grasp movements.
We discuss these results in the context of current
theories proposed to explain the object selection
processes underlying the control of hand action
