Conditions for a Linear Speed-Accuracy Trade-Off in Aimed Movements

1983 ◽  
Vol 35 (2) ◽  
pp. 279-296 ◽  
Author(s):  
Charles E. Wright ◽  
David E. Meyer
Keyword(s):  
Standard Deviation ◽  
Movement Time ◽  
Target Point ◽  
Home Position ◽  
Trade Off ◽  
Linear Speed ◽  
Temporal Precision ◽  
Fitts Law ◽  
Per Se ◽  
Speed Accuracy

A linear speed-accuracy trade-off has been found for rapid, precisely timed movements from a home position toward a target point. In this trade-off, We = K1 + K2(D/T), where D is the distance between the home position and the target, T is a pre-specified movement time, and We is the standard deviation of the distances actually moved. This result differs from Fitts' law, the commonly observed logarithmic trade-off in aimed movements. A new experiment with wrist rotations was performed to determine what conditions induce the linear trade-off rather than Fitts' law. Three types of condition are considered: movement brevity, feedback deprivation, and temporal precision. The experiment yielded a linear trade-off for precisely timed movements even when their durations significantly exceeded an amount of time (200 ms) sufficient to process visual feedback. This result suggests that the linearity does not depend on movement brevity and/or feedback deprivation per se. Instead it supports a temporal-precision hypothesis that the linear trade-off occurs when aimed movements must have precisely specified durations.

Can one explanation serve two laws?

1997 ◽  
Vol 20 (2) ◽  
pp. 325-325
Author(s):  
Howard N. Zelaznik ◽  
Robert W. Proctor
Keyword(s):  
Trade Off ◽  
Linear Speed ◽  
Fitts Law ◽  
Single Strategy ◽  
Speed Accuracy

Several issues are raised concerning the notion that a single strategy explains Fitts' law and the linear speed/accuracy trade-off. Two additional concerns are discussed: (1) distance is programmed, (2) the fact that movements produced without the aid of vision obey Fitts' law does not mean that sighted movements must be explained without regard to vision.

Speed and Accuracy of Eye-Gaze Pointing

1997 ◽  
Vol 85 (2) ◽  
pp. 705-718 ◽  
Author(s):  
Chia-Fen Chi ◽  
Chia-Liang Lin
Keyword(s):  
Eye Movement ◽  
Movement Time ◽  
Eye Gaze ◽  
Target Size ◽  
Trade Off ◽  
Starting Position ◽  
Fitts Law ◽  
Saccadic Movement ◽  
Speed Accuracy ◽  
Speed And Accuracy

The current experiment examined the speed-accuracy trade-off of saccadic movement between two targets. Ten subjects looked alternately at two targets as fast and as accurately as possible for 2 min. under different conditions of target size, distance between targets, and direction of eye movement. Saccadic movement of the left eye was tracked and recorded with an infrared eye monitoring device to compute the starting position, ending position, and duration of each saccadic movement. Eye-movement time was significantly related to target size and distance between targets, but the speed-accuracy trade-off was significantly different from that predicted by Fitts' Law. Reaction time was not significantly changed by the direction of eye movement.

scholarly journals Fifty years later: a neurodynamic explanation of Fitts' law

2006 ◽  
Vol 3 (10) ◽  
pp. 649-654 ◽  
Author(s):  
Dan Beamish ◽  
Shabana Ali Bhatti ◽  
I. Scott MacKenzie ◽  
Jianhong Wu
Keyword(s):  
Intrinsic Property ◽  
Motor Behaviour ◽  
Limited Capacity ◽  
Trade Off ◽  
Motor Circuit ◽  
Psychomotor Delay ◽  
Fitts Law ◽  
Human Motor ◽  
Speed Accuracy ◽  
Speed And Accuracy

An intrinsic property of human motor behaviour is a trade-off between speed and accuracy. This is classically described by Fitts' law, a model derived by assuming the human body has a limited capacity to transmit information in organizing motor behaviour. Here, we propose an alternative foundation, based on the neurodynamics of the motor circuit, wherein Fitts' law is an approximation to a more general relationship. In this formulation, widely observed inconsistencies with experimental data are a consequence of psychomotor delay. The methodology developed additionally provides a method to estimate the delay within the motor circuit from the speed-accuracy trade-off alone.

scholarly journals Comparison of speed-accuracy tradeoff between linear and nonlinear filtering algorithms for myocontrol

2018 ◽  
Vol 119 (6) ◽  
pp. 2030-2035 ◽  
Author(s):  
Cassie N. Borish ◽  
Adam Feinman ◽  
Matteo Bertucco ◽  
Natalie G. Ramsy ◽  
Terence D. Sanger
Keyword(s):  
Movement Time ◽  
Control Input ◽  
Bayesian Filtering ◽  
Success Rates ◽  
Bayesian Algorithm ◽  
Signal Processing Algorithm ◽  
Bayesian Filter ◽  
Fitts Law ◽  
Communication Devices ◽  
Speed Accuracy

Nonlinear Bayesian filtering of surface electromyography (EMG) can provide a stable output signal with little delay and the ability to change rapidly, making it a potential control input for prosthetic or communication devices. We hypothesized that myocontrol follows Fitts’ Law, and that Bayesian filtered EMG would improve movement times and success rates when compared with linearly filtered EMG. We tested the two filters using a Fitts’ Law speed-accuracy paradigm in a one-muscle myocontrol task with EMG captured from the dominant first dorsal interosseous muscle. Cursor position in one dimension was proportional to EMG. Six indices of difficulty were tested, varying the target size and distance. We examined two performance measures: movement time (MT) and success rate. The filter had a significant effect on both MT and success. MT followed Fitts’ Law and the speed-accuracy relationship exhibited a significantly higher channel capacity when using the Bayesian filter. Subjects seemed to be less cautious using the Bayesian filter due to its lower error rate and smoother control. These findings suggest that Bayesian filtering may be a useful component for myoelectrically controlled prosthetics or communication devices. NEW & NOTEWORTHY Whereas previous work has focused on assessing the Bayesian algorithm as a signal processing algorithm for EMG, this study assesses the use of the Bayesian algorithm for online EMG control. In other words, the subjects see the output of the filter and can adapt their own behavior to use the filter optimally as a tool. This study compares how subjects adapt EMG behavior using the Bayesian algorithm vs. a linear algorithm.

Movement dynamics in speed/accuracy trade-off

1997 ◽  
Vol 20 (2) ◽  
pp. 319-319 ◽  
Author(s):  
P. Morasso ◽  
V. Sanguineti
Keyword(s):  
Motor Control ◽  
Internal Source ◽  
Dynamic Nature ◽  
Trade Off ◽  
Fitts Law ◽  
Movement Dynamics ◽  
Weak Theories ◽  
Speed Accuracy ◽  
Partial Compensation

Fitts' law and the ΔΛ model are “weak” theories of motor control because they are limited to the kinematic aspects of movement and do not capture its essential dynamic nature. The internal source of “noise” that determines the speed/ accuracy trade-off can be associated with the partial compensation of movement-generated “parasitic” forces.

Effect of Variable Visual-Feedback Delay on Movement Time

2007 ◽  
Vol 51 (19) ◽  
pp. 1373-1377 ◽  
Author(s):  
Julio C. Mateo ◽  
Robert H. Gilkey ◽  
Jeffrey L. Cowgill
Keyword(s):  
Standard Deviation ◽  
Closed Loop ◽  
Movement Time ◽  
Three Dimensional ◽  
Feedback Delay ◽  
Fitts Law ◽  
Mean Delay ◽  
Delay Variability ◽  
The Mean ◽  
3D Virtual Environment

The effects of variable feedback delays on movement time were examined in a three-dimensional (3D) virtual environment. The participants' task was to use a 3D controller to position a cursor in targets as they appeared in a cubic workspace. Both the mean and standard deviation of the delay between the movement of the controller and the displayed position of the cursor were manipulated. In addition, the size of the targets and the distance between targets were varied. The results suggested that movement times are much more strongly affected by mean delay than by delay variability and that the effect of both variables is greatest during the closed-loop component of the movement. The results are discussed in relation to buffering strategies for reducing delay variability, Fitts' law, and other descriptions of aimed movements.

A Curvilinear Effect of Mental Workload on Mental Effort and Behavioral Adaptability: An Approach With the Pre-Ejection Period

2019 ◽  
Vol 62 (6) ◽  
pp. 928-939 ◽  
Author(s):  
Charlotte Mallat ◽  
Julien Cegarra ◽  
Christophe Calmettes ◽  
Rémi L. Capa
Keyword(s):  
Traffic Control ◽  
Task Difficulty ◽  
Mental Workload ◽  
Movement Time ◽  
Intermediate Level ◽  
Behavioral Strategies ◽  
Trade Off ◽  
Linear Effect ◽  
Speed Accuracy ◽  
Curvilinear Effect

Objective We tested Hancock and Szalma’s mental workload model, which has never been experimentally validated at a global level with the measure of the pre-ejection period (PEP), an index of beta-adrenergic sympathetic impact. Background Operators adapt to mental workload. When mental workload level increases, behavioral and physiological adaptability intensifies to reduce the decline in performance. However, if the mental workload exceeds an intermediate level, behavioral and physiological adaptability will decrease to protect individuals from excessive perturbations. This decrease is associated with a change in behavioral strategies and disengagement. Method The experimental task was a modified Fitts’ task used in Hancock and Caird. Five levels of task difficulty were computed. Behavioral and physiological adaptability was indexed by the performance with speed–accuracy trade-off and PEP reactivity. Results A curvilinear effect of task difficulty on PEP reactivity was significant, with high reactivity at the intermediate level but low reactivity at other levels. We observed a linear effect of task difficulty on error rate and a curvilinear effect on movement time. A decline in performance was noted up to the intermediate level, with a speed–accuracy trade-off above this level showing a faster movement time. Conclusion We observed for the first time behavioral and physiological adaptability as a function of mental workload. Application The results have important implications for the modeling of mental workload, particularly in the context of the performance-sensitive domain (car driving and air traffic control). They can help guide the design of human–computer interaction to maximize adaptive behavior, that is, the “comfort zone.”

A Dynamic Speed vs. Accuracy Trade-Off (DSAT) Paradigm for Measuring and Training Grip Force Control for Stroke Population

2009 ◽  
Author(s):  
Nam H. Kim ◽  
Michael Wininger ◽  
Gail Forrest ◽  
Thomas Edwards ◽  
William Craelius
Keyword(s):  
Grip Force ◽  
Motor Behavior ◽  
Movement Time ◽  
Dynamic Performance ◽  
Fundamental Principle ◽  
Difficulty Level ◽  
Trade Off ◽  
Stroke Population ◽  
Speed Accuracy ◽  
And Training

A fundamental principle of human motor behavior states that the accuracy of targeted movements relates reciprocally to their speed. This is quantified by Fitts’ Law, wherein movement time (MT) and index of difficulty (ID), the log2 ratio of target distance (A) to target height (H) has logarithmic linear relationship; MT = a+b·log2(2A/H) = a+b·ID. The slope, b (seconds/bits), measures targeting performance as the time spent at each difficulty level, expressed as bits of information to be processed by the neuromotor system [1, 2]. Fitts’ paradigm is a common measure of the kinematic performance of the upper limb, but has not been applied to its dynamic performance. Herein, we developed a dynamic speed-accuracy trade-off (DSAT) test of grip force modulation, which can be used both for assessment and training.

scholarly journals Consistent Individual Tendencies in Motor Speed-Accuracy Trade-Off

2021 ◽  
Author(s):  
Matheus Pacheco ◽  
Charley W. Lafe ◽  
Che-Hsiu Chen ◽  
Tsung-Yu Hsieh
Keyword(s):  
Motor Control ◽  
Movement Time ◽  
Motor Speed ◽  
Bayesian Analyses ◽  
Trade Off ◽  
Practice Condition ◽  
Speed Accuracy ◽  
Mean Variance ◽  
Interpretation Of Results

The literature of Speed-Accuracy Trade-Off (SAT) in motor control has evidenced individuality in the preference to trade different aspects (mean, variance) of spatial and temporal errors. Nonetheless, to the best of our knowledge, how robust this preference is has not been properly tested. Thirty participants performed nine conditions with different time and spatial criteria over two days (scanning). In-between these scanning conditions, individuals performed a practice condition that required modifications of the individuals’ preferences in SAT. Through Bayesian analyses, we found that, despite individuals demonstrating changes during practice, decreasing movement time, they did not modify how they performed the scanning conditions. This is evidence for a robust SAT individual tendency. We discuss how such individuality could modify how individuals perform within/between SAT criteria, and what this means for interpretation of results.

Dual Goals for Speed and Accuracy on the Same Performance Task

2012 ◽  
Vol 11 (3) ◽  
pp. 118-126 ◽  
Author(s):  
Olive Emil Wetter ◽  
Jürgen Wegge ◽  
Klaus Jonas ◽  
Klaus-Helmut Schmidt
Keyword(s):  
Memory Scanning ◽  
Performance Task ◽  
Performance Tasks ◽  
Trade Off ◽  
Test Experiment ◽  
Trade Offs ◽  
New Finding ◽  
Sternberg Paradigm ◽  
Speed Accuracy ◽  
Speed And Accuracy

In most work contexts, several performance goals coexist, and conflicts between them and trade-offs can occur. Our paper is the first to contrast a dual goal for speed and accuracy with a single goal for speed on the same task. The Sternberg paradigm (Experiment 1, n = 57) and the d2 test (Experiment 2, n = 19) were used as performance tasks. Speed measures and errors revealed in both experiments that dual as well as single goals increase performance by enhancing memory scanning. However, the single speed goal triggered a speed-accuracy trade-off, favoring speed over accuracy, whereas this was not the case with the dual goal. In difficult trials, dual goals slowed down scanning processes again so that errors could be prevented. This new finding is particularly relevant for security domains, where both aspects have to be managed simultaneously.

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