Anticipatory posture control during a complex prehension task


Invited talk

Speaker : Dr. William Land

Event: 48. Kongress der Deutschen Gesellschaft fuer Psychologi

Universitaet Bielefeld
Universitaetsstrasse 25
33615 Bielefeld, Germany
Date: 25/09/2012


Traditionally, object manipulation has been hand- and arm-focused.
However, more recently, the coordination of the entire body is being
considered vital to the understanding of action planning and object
manipulation. To explore this topic, we examined the extent to which
anticipation of a prehension task influenced preceding postural coordination.
Specifically, we investigated a task which required participants to walk up
to a drawer, open the drawer, and then grasp and place an object within the
drawer. The starting placement of the object within the drawer and the final
placement of the object in the drawer were varied across trials in either a
blocked (i.e., trials of the same start and end location were repeated
consecutively) or random fashion. Of primary interest was the posture adopted
at the point of drawer handle grasp prior to prehension. A secondary interest
was whether preceding postures influenced postures in subsequent trials.
Results indicated that participants adopted different postures with respect
to different starting and placement locations of the subsequent prehension
task. Specifically, differences in shoulder angle, position the participants
grasped the drawer handle, distance the participants opened the drawer, and
the position participants stood relative to the drawer were observed with
respect to both the start and end placement of the forthcoming prehension
task. However, the start position was found to have a larger influence on the
adopted posture than the end placement position. In addition, the adopted
postures were more consistent in blocked trials than in mixed trials,
suggesting an additional retrospective effect. Overall, our findings suggest
that whole-body posture planning represents a confluence between prior motor
planning and the anticipation of upcoming task demands.


William Land




Bielefeld, Germany


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