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Functional stabilization of unstable systems

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Date Issued:
2000
Summary:
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 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).
Title: Functional stabilization of unstable systems.
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Name(s): Foo, Patrick Stephen
Florida Atlantic University, Degree Grantor
Kelso, J. A. Scott, Thesis Advisor
Type of Resource: text
Genre: Electronic Thesis Or Dissertation
Issuance: monographic
Date Issued: 2000
Publisher: Florida Atlantic University
Place of Publication: Boca Raton, Fla.
Physical Form: application/pdf
Extent: 214 p.
Language(s): English
Summary: 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 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).
Identifier: 9780599953130 (isbn), 12656 (digitool), FADT12656 (IID), fau:9538 (fedora)
Note(s): Thesis (Ph.D.)--Florida Atlantic University, 2000.
Subject(s): Psychology, Experimental
Human mechanics
Held by: Florida Atlantic University Libraries
Persistent Link to This Record: http://purl.flvc.org/fcla/dt/12656
Sublocation: Digital Library
Use and Reproduction: Copyright © is held by the author with permission granted to Florida Atlantic University to digitize, archive and distribute this item for non-profit research and educational purposes. Any reuse of this item in excess of fair use or other copyright exemptions requires permission of the copyright holder.
Use and Reproduction: http://rightsstatements.org/vocab/InC/1.0/
Host Institution: FAU
Is Part of Series: Florida Atlantic University Digital Library Collections.