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A developmental transition in prehension modeled as a cusp catastrophe
R H Wimmers1, G J Savelsbergh, J van der Kamp
1Institute for Fundamental and Clinical Human Movement Sciences, Amsterdam/Nijmegen, The Netherlands.
Developmental Psychobiology
|February 7, 1998
Summary
Infant reaching and grasping transitions exhibit characteristics of a discontinuous phase transition, specifically a catastrophe. Arm weight and circumference significantly influence this developmental control.
Area of Science:
- Developmental psychology
- Motor control
- Dynamical systems theory
Background:
- Early infant motor development involves complex transitions.
- Understanding developmental changes as continuous or discontinuous is crucial.
- Catastrophe theory offers a framework for abrupt behavioral shifts.
Purpose of the Study:
- To model the developmental shift from reaching without grasping to reaching with grasping in infants.
- To determine if this motor milestone exhibits characteristics of a discontinuous phase transition (catastrophe).
Main Methods:
- A cross-sectional study of 58 infants aged 60-408 days.
- Infants reached for balls in a controlled setup, with reaches and grasps video-recorded.
- A cusp catastrophe model was statistically compared against linear and logistic regression models.
Main Results:
- The cusp catastrophe model provided a significantly better fit to the data than linear regression (p < .001).
- Akaike's Information Criterion indicated the cusp model outperformed the logistic model.
- Arm weight and arm circumference were identified as significant control parameters influencing the transition.
Conclusions:
- The developmental change in infant reaching and grasping aligns with a discontinuous phase transition model.
- Arm dimensions, specifically weight and circumference, play a key role in controlling this motor skill acquisition.
- Catastrophe theory provides a valuable lens for analyzing abrupt developmental changes in motor behavior.