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Body scale and the development of prehension
K M Newell1, D M Scully, F Tenenbaum
1Department of Kinesiology, University of Illinois, Urbana Champaign 61801.
Developmental Psychobiology
|January 1, 1989
Summary
Body scale significantly impacts grip coordination development in children and adults. When object size is scaled to hand size, common dimensionless ratios emerge, revealing predictable grasping patterns and limb orientations.
Area of Science:
- Developmental Psychology
- Motor Control
- Biomechanics
Background:
- Grip coordination is crucial for object manipulation.
- Understanding developmental changes in prehension is essential.
- The role of body scale in motor development requires further investigation.
Purpose of the Study:
- To determine if dimensionless ratios define critical points in grip coordination shifts.
- To examine the influence of object size and hand size scaling on grasping patterns.
- To identify common grip configurations across different age groups.
Main Methods:
- Preschoolers and adults performed a displacement grasping task with varying object sizes.
- Analysis focused on grip coordination patterns and limb orientations.
- Dimensionless ratios were calculated based on object and hand size.
Main Results:
- An interaction between task and organismic constraints influenced grasping patterns.
- Scaled object-to-hand size revealed common dimensionless ratios for grip and limb orientation.
- Five grip configurations explained most of the grip variance in both age groups.
Conclusions:
- Body scale plays a significant role in the development of motor coordination.
- Prehension development appears to be constrained by physical action limitations.
- Dimensionless ratios offer a framework for understanding age-invariant grasping principles.