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Intercepting free falling objects: better use Occam's razor than internalize Newton's law
Robin Baurès1, Nicolas Benguigui, Michel-Ange Amorim
1Université Paris-Sud, UPRES EA 4042, Contrôle Moteur et Perception, 91405, Orsay, France. robin.baures@u-psud.fr
Vision Research
|September 22, 2007
Summary
Human interceptive actions involving free-falling objects may not use a precise internal gravity model. Instead, implicit physics knowledge likely guides timing, with optical information used online.
Area of Science:
- Human motor control
- Perception-action coupling
- Internal models of physics
Background:
- Recent studies suggest humans possess a quantitative internal model of gravity.
- This model purportedly allows accurate prediction of time-to-contact (TTC) for free-falling objects.
- This facilitates precise interceptive actions.
Purpose of the Study:
- To critically review experimental evidence supporting an internal gravity model for interceptive actions.
- To propose an alternative explanation for timing in free-fall interception.
- To identify gaps in current understanding of how physics knowledge and optical information are integrated.
Main Methods:
- Theoretical review and discussion of existing experimental paradigms.
- Analysis of methodological concerns in studies of gravity's role in interception.
- Conceptual framework development for implicit physics knowledge in motor control.
Main Results:
- Significant theoretical and methodological concerns challenge the existence of an accurate, predictive internal model of gravity.
- Evidence suggests that 'qualitative implicit physics knowledge' of gravity's effects is used.
- This knowledge acts as approximate pre-information influencing action timing.
Conclusions:
- The assumption of a precise internal gravity model for intercepting free-falling objects is questionable.
- Implicit physics knowledge, rather than an exact model, likely guides timing.
- Further research is needed to elucidate the integration of implicit knowledge and online optical information for interceptive timing.
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