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Estimation of Contact Regions Between Hands and Objects During Human Multi-Digit Grasping
Published on: April 21, 2023
Corrective processes in grasping after perturbations of object size
Constanze Hesse1, Volker H Franz
1Department of Experimental Psychology, Justus-Liebig-Universität, Giessen, Germany. constanze.hesse@psy.lmu.de
Journal of Motor Behavior
|April 16, 2009
Summary
Human grip adaptation to object size changes occurs through smooth adjustments, not by reprogramming motor commands. Corrections are faster with later perturbations, indicating efficient motor control.
Area of Science:
- Motor control
- Human grasping
- Biomechanics
Background:
- Grip adaptation is crucial for interacting with objects.
- Previous theories suggested reprogramming motor programs for new object sizes.
- Understanding corrective mechanisms in grasping is essential.
Purpose of the Study:
- To investigate how humans adapt their grip to changing object sizes.
- To examine the influence of perturbation timing, visual feedback, and size on grip adjustments.
- To test the hypothesis of motor program reprogramming versus continuous adaptation.
Main Methods:
- Utilized a size perturbation paradigm in three experiments.
- Manipulated perturbation timing (early/late), visual feedback availability, and perturbation size (small/large).
- Analyzed grip aperture adjustments over time.
Main Results:
- Grip corrections were executed faster following late perturbations.
- Visual information about hand movement had a minimal impact on corrections.
- Adaptations primarily involved smooth, continuous changes in grip aperture, not superimposed motor programs.
Conclusions:
- Human grip adaptation to object size relies on continuous adjustments rather than complete motor program substitution.
- Feedforward mechanisms appear to play a significant role in corrective grasping.
- The findings challenge existing theories on motor reprogramming during adaptation.
