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SPEED/ACCURACY TRADEOFFS IN TARGET DIRECTED MOVEMENTS

Plamondon, Rejean and Alimi, Adel M. (1997) SPEED/ACCURACY TRADEOFFS IN TARGET DIRECTED MOVEMENTS.

Short Abstract:

This paper presents a critical survey of the scientific literature dealing with the speed/accuracy tradeoffs of rapid-aimed movements. It highlights the numerous mathematical and theoretical interpretations that have been proposed over recent decades from the different studies that have been conducted on this topic. Although the variety of points of view reflects the richness of the field as well as the high degree of interest that such basic phenomena represent in the understanding of human movements, it questions the validity of many models with respect to their capacity to explain all the basic observations consistently reported in the field. In this perspective, this paper summarizes the kinematic theory of rapid human movements, proposed recently by the first author, and analyzes its predictions in the context of speed/accuracy tradeoffs. Numerous data available from the scientific literature are reanalyzed and reinterpreted in the context of this new theory. It is shown that the various aspects of the speed/accuracy tradeoffs can be taken into account by considering the asymptotic behavior of a large number of coupled linear systems, from which a delta-lognormal law can be derived, to describe the velocity profile of an end-effector driven by a neuromuscular synergy. This law not only describes velocity profiles almost perfectly, but it also predicts the kinematic properties of simple rapid movements and provides a consistent framework for the analysis of different types of rapid movements using a quadratic (or power) law that emerges from the model.

Long Abstract:

This paper presents a critical survey of the scientific literature dealing with the speed/accuracy tradeoffs of rapid-aimed movements. It highlights the numerous mathematical and theoretical interpretations that have been proposed over recent decades from the different studies that have been conducted on this topic. Although the variety of points of view reflects the richness of the field as well as the high degree of interest that such basic phenomena represent in the understanding of human movements, it questions the validity of many models with respect to their capacity to explain all the basic observations consistently reported in the field. In this perspective, this paper summarizes the kinematic theory of rapid human movements, proposed recently by the first author, and analyzes its predictions in the context of speed/accuracy tradeoffs. Numerous data available from the scientific literature are reanalyzed and reinterpreted in the context of this new theory. It is shown that the various aspects of the speed/accuracy tradeoffs can be taken into account by considering the asymptotic behavior of a large number of coupled linear systems, from which a delta-lognormal law can be derived, to describe the velocity profile of an end-effector driven by a neuromuscular synergy. This law not only describes velocity profiles almost perfectly, but it also predicts the kinematic properties of simple rapid movements and provides a consistent framework for the analysis of different types of rapid movements using a quadratic (or power) law that emerges from the model.

Keywords:	Speed/accuracy tradeoffs, Fitts' law, central limit theorem, velocity profile, delta-lognormal law, quadratic law, power law.
Subjects:	Psychology: Applied Cognitive Psychology Psychology: Cognitive Psychology Computer Science: Statistical Models
ID code:	bbs00000498
Deposited by:	Rejean Plamondon on 01 May 2001