On the Relative Salience of Euclidean, Affine, and Topological Structure for 3-D Form Discrimination

Perception ◽  
1998 ◽  
Vol 27 (3) ◽  
pp. 273-282 ◽  
Author(s):  
James T Todd ◽  
Lin Chen ◽  
J Farley Norman
Keyword(s):  
Topological Structure ◽  
Three Dimensional ◽  
Reaction Times ◽  
Error Rates ◽  
Form Discrimination ◽  
Line Segments ◽  
Match To Sample ◽  
Perceptual Salience ◽  
Object Properties ◽  
Relative Salience

A match-to-sample task was performed, in which observers compared configurations of line segments presented stereoscopically in different three-dimensional orientations. Several different structural properties of these configurations were manipulated, including the relative orientations of line segments (a Euclidean property), their coplanarity (an affine property), and their patterns of cointersection (a topological property). Although the differences in these properties to be detected were all metrically equivalent, they varied dramatically in their relative perceptual salience, such that the error rates and reaction times in the three conditions varied by as much as 400%. Performance was highest in the topological condition, intermediate in the affine condition, and lowest in the Euclidean condition. These findings suggest that the relative perceptual salience of object properties may be systematically related to their structural stability under change, in a manner that is similar to the Klein hierarchy of geometries.

scholarly journals The Proficiency for Distinguishing Faces is Independent of the Proficiency for Remembering Them

2019 ◽  
Author(s):  
Catrina Hacker ◽  
Irving Biederman
Keyword(s):  
Face Recognition ◽  
Face Perception ◽  
Reaction Times ◽  
Quantitative Measure ◽  
Error Rates ◽  
Perceptual Discrimination ◽  
Face Memory ◽  
Match To Sample ◽  
Perceptual Difficulty ◽  
Face Similarity

Tests of face recognition implicitly assume it to be an undifferentiated ability. However, several possible independent components could comprise face recognition proficiency, such as those for the perceptual discrimination of faces, face memory, and the ability to generalize across viewpoints. We assessed two possible components of face recognition ability: the proficiency for the perceptual discrimination of faces using a quantitative measure of face similarity and the proficiency for remembering those faces using a minimal delayed match-to-sample task. We document a strong cost of delay on error rates and mean correct reaction times in face matching. We further demonstrate that the slope of performance over increased perceptual difficulty is parallel for each of three levels of delay. These results provide evidence, by additive factors logic, that face memory and face perception are independent processes within subjects. Finally, we document an independence of the proficiencies for face memory and face perception across subjects.

Traffic Signal Color Recognition Is a Problem for Both Protan and Deutan Color-Vision Deficients

2003 ◽  
Vol 45 (3) ◽  
pp. 495-503 ◽  
Author(s):  
David A. Atchison ◽  
Carol A. Pedersen ◽  
Stephen J. Dain ◽  
Joanne M. Wood
Keyword(s):  
Color Vision ◽  
Response Times ◽  
Reaction Times ◽  
Error Rates ◽  
Traffic Signal ◽  
White Background ◽  
Signal Design ◽  
Traffic Light ◽  
Light Signals ◽  
Signal Color

We investigated the effect of color-vision deficiency on reaction times and accuracy of identification of traffic light signals. Participants were 20 color-normal and 49 color-deficient males, the latter divided into subgroups of different severity and type. Participants performed a tracking task. At random intervals, stimuli simulating standard traffic light signals were presented against a white background at 5° to right or left. Participants identified stimulus color (red/yellow/green) by pressing an appropriate response button. Mean response times for color normals were 525, 410, and 450 ms for red, yellow, and green lights, respectively. For color deficients, response times to red lights increased with increase in severity of color deficiency, with deutans performing worse than protans of similar severity: response times of deuteranopes and protanopes were 53% and 35% longer than those of color normals. A similar pattern occurred for yellow lights, with deuteranopes and protanopes having increased response times of 85% and 53%, respectively. For green lights, response times of all groups were similar. Error rates showed patterns similar to those of response times. Contrary to previous studies, deutans performed much worse than protans of similar severity. Actual or potential applications of this research include traffic signal design and driver licensing.

scholarly journals The effects of gamelike features and test location on cognitive test performance and participant enjoyment

PeerJ ◽  
2016 ◽  
Vol 4 ◽  
pp. e2184 ◽  
Author(s):  
Jim Lumsden ◽  
Andy Skinner ◽  
Andy T. Woods ◽  
Natalia S. Lawrence ◽  
Marcus Munafò
Keyword(s):  
Test Performance ◽  
Cognitive Task ◽  
Reaction Times ◽  
Error Rates ◽  
Cognitive Testing ◽  
Quality Data ◽  
Cognitive Test ◽  
Test Location ◽  
Gamelike Features ◽  
Time Accuracy

Computerised cognitive assessments are a vital tool in the behavioural sciences, but participants often view them as effortful and unengaging. One potential solution is to add gamelike elements to these tasks in order to make them more intrinsically enjoyable, and some researchers have posited that a more engaging task might produce higher quality data. This assumption, however, remains largely untested. We investigated the effects of gamelike features and test location on the data and enjoyment ratings from a simple cognitive task. We tested three gamified variants of the Go-No-Go task, delivered both in the laboratory and online. In the first version of the task participants were rewarded with points for performing optimally. The second version of the task was framed as a cowboy shootout. The third version was a standard Go-No-Go task, used as a control condition. We compared reaction time, accuracy and subjective measures of enjoyment and engagement between task variants and study location. We found points to be a highly suitable game mechanic for gamified cognitive testing because they did not disrupt the validity of the data collected but increased participant enjoyment. However, we found no evidence that gamelike features could increase engagement to the point where participant performance improved. We also found that while participants enjoyed the cowboy themed task, the difficulty of categorising the gamelike stimuli adversely affected participant performance, increasing No-Go error rates by 28% compared to the non-game control. Responses collected online vs. in the laboratory had slightly longer reaction times but were otherwise very similar, supporting other findings that online crowdsourcing is an acceptable method of data collection for this type of research.

scholarly journals Another Warning about Median Reaction Time --- Version of 11 Feb 2020

2020 ◽  
Author(s):  
Jeff Miller
Keyword(s):  
Type I Error ◽  
Reaction Times ◽  
Error Rates ◽  
Type I ◽  
Experimental Conditions ◽  
Type I Error Rates ◽  
Correction Technique ◽  
Inflated Type ◽  
The Mean ◽  
Rt Distributions

Contrary to the warning of Miller (1988), Rousselet and Wilcox (2020) argued that it is better to summarize each participant’s single-trial reaction times (RTs) in a given condition with the median than with the mean when comparing the central tendencies of RT distributions across experimental conditions. They acknowledged that median RTs can produce inflated Type I error rates when conditions differ in the number of trials tested, consistent with Miller’s warning, but they showed that the bias responsible for this error rate inflation could be eliminated with a bootstrap bias correction technique. The present simulations extend their analysis by examining the power of bias-corrected medians to detect true experimental effects and by comparing this power with the power of analyses using means and regular medians. Unfortunately, although bias-corrected medians solve the problem of inflated Type I error rates, their power is lower than that of means or regular medians in many realistic situations. In addition, even when conditions do not differ in the number of trials tested, the power of tests (e.g., t-tests) is generally lower using medians rather than means as the summary measures. Thus, the present simulations demonstrate that summary means will often provide the most powerful test for differences between conditions, and they show what aspects of the RT distributions determine the size of the power advantage for means.

scholarly journals BLOCK SLOPE IS THE MAIN DETERMINANT OF BLOCK PHASE PERFORMANCE IN SWIMMING

2021 ◽  
Vol 27 (1) ◽  
pp. 30-35
Author(s):  
Uğur ÖDEK ◽  
Feza KORKUSUZ ◽  
Sadettin KİRAZCI
Keyword(s):  
Three Dimensional ◽  
Reaction Times ◽  
Level Of Evidence ◽  
Kinematic Data ◽  
Main Determinant ◽  
Results Of Treatment ◽  
Block Height ◽  
Dependent Variables ◽  
Competitive Swimmers ◽  
Main Factor

ABSTRACT Introduction Swimming starts are an important component for decreasing the total race time, especially in short events. In this phase of swimming, the aim is to increase performance using many different techniques and starting platforms. Objectives The effects of height and slope of the starting block on kick-start performance were assessed in this study. Methods Six male competitive swimmers performed 24 kick-starts using four block settings: 65 cm & 75 cm flat and 65 cm & 75 cm sloped. Two-dimensional kinetic and three-dimensional kinematic data were analyzed, including average and maximum horizontal/vertical forces and impulses; reaction times; movement and block times; and take-off vertical/horizontal velocities. Two-way within-subject design ANOVAs were implemented to test the effects of block height and slope on the kinetic and kinematic variables. Results Block slope was the main factor affecting most of the dependent variables. Shorter block and movement times, greater average and maximum vertical forces, vertical impulse, and maximum horizontal force were found for the sloped settings. An inverse relationship was found between block height and 0-5 m times. Conclusion Based on the results, blocks with height of 75 cm and slope of 10° provided better results in swimmers’ performance in the block phase. Level of evidence II, Therapeutic Studies -Investigating the Results of Treatment

Computational Support for Interactive Cable Harness Routing and Design

1993 ◽  
Author(s):  
Andrew B. Conru ◽  
Mark R. Cutkosky
Keyword(s):  
Cost Function ◽  
Topological Structure ◽  
Three Dimensional ◽  
Initial Guess ◽  
Local Minima ◽  
Cable Harness ◽  
Physical Constraints ◽  
Computational Support ◽  
Bending Radius

Abstract We describe a system for routing cable harnesses in complex, three-dimensional environments. The approach taken is to automate the basic routing process as much as possible, while allowing designers to guide the system and modify the numerically generated results at any stage. The system begins by quickly generating a coarse routing based on an initial guess of the cable harness configuration (topological structure). Paths are then successively refined to minimize a cost function, while satisfying physical constraints such as minimum bending radius. Human input is useful both for guiding the system away from local minima and for responding to case-specific constraints not encoded in the router.

scholarly journals The Sustained Attention to Response Task Shows Lower Cingulo-Opercular and Frontoparietal Activity in People with Narcolepsy Type 1: An fMRI Study on the Neural Regulation of Attention

2020 ◽  
Vol 10 (7) ◽  
pp. 419
Author(s):  
Jari K. Gool ◽  
Ysbrand D. van der Werf ◽  
Gert Jan Lammers ◽  
Rolf Fronczek
Keyword(s):  
Sustained Attention ◽  
Group Performance ◽  
Brain Activity ◽  
Reaction Times ◽  
Vigilance Task ◽  
Error Rates ◽  
Time On Task ◽  
Related Activity ◽  
Response Task

Vigilance complaints often occur in people with narcolepsy type 1 and severely impair effective daytime functioning. We tested the feasibility of a three-level sustained attention to response task (SART) paradigm within a magnetic resonance imaging (MRI) environment to understand brain architecture underlying vigilance regulation in individuals with narcolepsy type 1. Twelve medication-free people with narcolepsy type 1 and 11 matched controls were included. The SART included four repetitions of a baseline block and two difficulty levels requiring moderate and high vigilance. Outcome measures were between and within-group performance indices on error rates and reaction times, and functional MRI (fMRI) parameters: mean activity during the task and between-group activity differences across the three conditions and related to changes in activation over time (time-on-task) and error-related activity. Patients—but not controls—made significantly more mistakes with increasing difficulty. The modified SART is a feasible MRI vigilance task showing similar task-positive brain activity in both groups within the cingulo-opercular, frontoparietal, arousal, motor, and visual networks. During blocks of higher vigilance demand, patients had significantly lower activation in these regions than controls. Patients had lower error-related activity in the left pre- and postcentral gyrus. The time-on-task activity differences between groups suggest that those with narcolepsy are insufficiently capable of activating attention- and arousal-related regions when transitioning from attention initiation to stable attention, specifically when vigilance demand is high. They also show lower inhibitory motor activity in relation to errors, suggesting impaired executive functioning.

The effect of overall stimulus velocity on motion parallax

2008 ◽  
Vol 25 (1) ◽  
pp. 3-15 ◽  
Author(s):  
YING ZHANG ◽  
PETER H. SCHILLER
Keyword(s):  
Motion Parallax ◽  
Three Dimensional ◽  
Reaction Times ◽  
Visual Display ◽  
Stimulus Movement ◽  
Stimulus Velocity ◽  
Target Region ◽  
Performance Accuracy ◽  
Dimensional Object

This study examined the effectiveness with which motion parallax information can be utilized by rhesus monkeys for depth perception. A visual display comprised of random-dots that mimicked a rigid, three-dimensional object rocking back and forth was used. Differential depth was produced by presenting sub-regions of the dots moving at different velocities from the rest of dots in the display. The tasks for the monkeys were to detect or discriminate a target region that was protruding the furthest from the background plane. To understand the role of stimulus movement, we examined the accuracy and the rapidity of the saccadic responses as a function of rocking velocity of the entire three-dimensional object. The results showed that performance accuracy improved and reaction times decreased with increasing rocking velocities. The monkeys can process the motion parallax information with remarkable rapidity such that the average reaction time ranged between 212 and 246 milliseconds. The data collected suggest that the successive activation of just two sets of cones is sufficient to perform the task.

Proprioceptive control of interjoint coordination

1995 ◽  
Vol 73 (2) ◽  
pp. 273-284 ◽  
Author(s):  
Claude Ghez ◽  
Robert Sainburg
Keyword(s):  
Internal Model ◽  
Dynamic Properties ◽  
Three Dimensional ◽  
Specific Response ◽  
Proprioceptive Information ◽  
Dynamic Interactions ◽  
Line Segments ◽  
Interjoint Coordination ◽  
Straight Line ◽  
Interaction Torques

This paper reviews a series of experiments comparing intact controls with functionally deafferented patients to determine the role of proprioception in controlling dynamic interactions between limb segments during movement. We examine the control of hand path in a planar movement-reversal task and in a familiar three-dimensional gesture with similar biomechanical characteristics. In the planar task subjects had to move their hand out and back along a series of straight-line segments in the horizontal plane without visual feedback. The lengths and directions of the target line segments were chosen to require different amounts of shoulder motion while requiring the same elbow excursion. In controls, hand paths were, as required, straight with sharp bends at the outermost point. In patients, however, distinctive errors appeared at movement reversals, consisting of widened hand paths resulting from desynchronization in the reversals of elbow and shoulder motions. These errors reflected an inability to program elbow muscle contractions in accord with interaction torques produced at the elbow by variations in acceleration of the shoulder. The reversal errors were substantially reduced after patients had practiced for a few trials while visually monitoring movements of their arm. The improvement was not limited to the direction where they had practiced with vision, but also extended to other directions in which the elbow torques were different. This suggests that practice with vision of the arm served to improve the general rules that subjects used to plan movement, rather than simply improving the performance of a specific response. Similar to their performance on the planar task, the patients made errors in interjoint coordination during unconstrained three-dimensional gestures with movement reversals. We conclude (i) that both the planning and the learning of movement required an internal model of the dynamic properties of the limb that takes account of interaction torques acting at different joints; (ii) that this internal model is normally established and updated using proprioceptive information; but (iii) that when proprioception is lacking, vision of the limb in motion partially substitutes for proprioception.Key words: proprioception, multijoint coordination, limb movement, multijoint dynamics, deafferentation.

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