Current Search: Foo, Patrick Stephen (x)
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Title
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Functional stabilization of unstable systems.
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Creator
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Foo, Patrick Stephen, Florida Atlantic University, Kelso, J. A. Scott
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Abstract/Description
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Humans are often faced with tasks that require stabilizing inherently unstable situations. We performed four experiments to explore the nature of functional stabilization. In Experiment 1 participants balanced a pole until a time criterion was reached. The geometry, mass, and characteristic "fall time" of the pole were manipulated. Distributions of timing between pole and hand velocities showed strong action-perception coupling. When actions demonstrated a potential for failure, the period of...
Show moreHumans are often faced with tasks that require stabilizing inherently unstable situations. We performed four experiments to explore the nature of functional stabilization. In Experiment 1 participants balanced a pole until a time criterion was reached. The geometry, mass, and characteristic "fall time" of the pole were manipulated. Distributions of timing between pole and hand velocities showed strong action-perception coupling. When actions demonstrated a potential for failure, the period of hand oscillation correlated significantly with the "time to balance" (t bal=theta/theta.), where q is pole angle re: the vertical balance point, but not other quantities such as theta and theta. alone. This suggested that participants were attending to available t bal information during critical situations. In a model analysis and simulation, we demonstrated how discrete t bal information may be used to adjust the parameters of a controller to perform this task. In Experiment 2 participants balanced a virtual inverted pendulum under manipulations designed: (1) to decouple the mechanics of the system from its visual image; (2) to alter the mapping of perception and action; and (3) to perturb successful balancing. A replication of the correlation analysis of Experiment 1 revealed that across all conditions, significant relationships existed between visually specified t -variables and hand oscillation during critical motions of the pole. These results suggested that participants use the same t bal information to successfully stabilize both virtual and physical unstable systems, despite quite dramatic visual and mechanical transformations. In Experiments 3 and 4 we investigated how parts of the body, or individuals in a social dyad cooperate to perform a functional stabilization task. Participants balanced a pole either intermanually (using 2 separate hands) or interpersonally (2 persons each using their preferred right hand) until a time criterion was reached. Although the magnitudes of the forces exerted by each hand were different, an analysis of the timing of the forces revealed that intermanual (interpersonal) participants developed a consistent antiphase (inphase) coordination pattern. These different coordination patterns allowed for the recruitment of previously unavailable efferent and afferent connections to produce the net forces that served to stabilize the pole via theta. (see Experiment 1).
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Date Issued
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2000
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PURL
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http://purl.flvc.org/fcla/dt/12656
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Subject Headings
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Psychology, Experimental, Human mechanics
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Format
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Document (PDF)
