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Is object texture a constraint on human prehension?: kinematic evidence.
P L Weir1, C L MacKenzie, R G Marteniuk
1Department of Kinesiology, University of Waterloo.
Journal of Motor Behavior
|September 1, 1991
Summary
Object texture significantly impacts human prehension timing, particularly the grasp phase. Slippery surfaces increase movement time, unlike object weight which does not affect the initial movement.
Area of Science:
- Biomechanics
- Human Motor Control
- Robotics
Background:
- Understanding how intrinsic object properties influence human prehension is crucial for fields like robotics and ergonomics.
- Previous research established that object weight does not affect the free-motion phase of prehension.
Purpose of the Study:
- To investigate the effect of object surface texture on the transport and grasp components of human prehension.
- To determine if texture influences kinematic measures during object manipulation.
Main Methods:
- Infrared markers recorded finger, thumb, and wrist kinematics using a WATSMART system.
- Participants interacted with cylindrical dowels of varying textures: plain metal, Vaseline-coated (slippery), and sandpaper-covered (rough).
Main Results:
- Object texture significantly affected temporal kinematic measures, including movement time and time to lift the object.
- Slippery dowels resulted in significantly greater movement times compared to normal and rough dowels.
- Increased time for slippery objects was primarily due to a longer interval between initial contact and object lift.
Conclusions:
- Object texture, like weight, primarily influences the finger-object interaction phase of prehension, not the initial transport phase.
- Future research should differentiate between inertial and surface friction effects during object contact.