Psychophysical Methodology: Comparisons within the Method of Limits

1969 ◽  
Vol 28 (2) ◽  
pp. 503-514 ◽  
Author(s):  
Robert M. Herrick
Keyword(s):  
Stimulus Intensity ◽  
Present Method ◽  
Psychophysical Experiment ◽  
Psychophysical Data ◽  
Threshold Distribution ◽  
The Mean

Assume that, in a “Yes”—“No” psychophysical experiment, the probability of a “Yes” response increases as the stimulus intensity increases. Then, on the basis of probability considerations (a) the mean threshold of the descending method of limits (DML) is greater than the mean threshold of the ascending method of limits (AML) and (b) σ of the DML threshold distribution may be greater than, equal to, or less than σ of the AML threshold distribution. The implications of these and other deductions are considered with respect to analyses of psychophysical data. For example, one deduction indicates that the present method for evaluating errors of habituation and expectation is wrong. Data that support the deductions are included.

scholarly journals A note on detecting statistical outliers in psychophysical data

2016 ◽  
Author(s):  
Pete R. Jones
Keyword(s):  
Monte Carlo ◽  
Monte Carlo Simulations ◽  
Interquartile Range ◽  
Psychophysical Experiment ◽  
Parametric Methods ◽  
Absolute Deviation ◽  
Matlab Code ◽  
Psychophysical Data ◽  
Sampling Distributions ◽  
The Mean

AbstractThis paper considers how best to identify statistical outliers in psychophysical datasets, where the underlying sampling distributions are unknown. Eight methods are described, and each is evaluated using Monte Carlo simulations of a typical psychophysical experiment. The best method is shown to be one based on a measure of absolute-deviation known as Sn. This method is shown to be more accurate than popular heuristics based on standard deviations from the mean, and more robust than non-parametric methods based on interquartile range. Matlab code for computing Sn is included.

Quantitative studies of the reactions to horizontal angular accelerations in axolotls. I. The head-turning reflexes of normal animals

1977 ◽  
Vol 66 (1) ◽  
pp. 1-14
Author(s):  
K. Brandle
Keyword(s):  
Stimulus Intensity ◽  
Time Course ◽  
Maximum Velocity ◽  
Afferent Input ◽  
Head Turning ◽  
Mean Values ◽  
Quantitative Studies ◽  
The Mean ◽  
Negative Exponential ◽  
Total Angle

1. Artifically metamorphosed axolotls were exposed to both brief (impulse) and long-lasting horizontal angular accelerations on a turn-table. The animals responded with a head-turning reaction. 2. The general course of the reaction to impulse acceleration was independent of stimulus intensity. The velocity of the head movement first increased to a maximum exponentially and then decreased in a negative exponential manner. Stimulus intensity had a linear relationship to the mean maximum velocity and mean total angle covered by head-turning. The average velocity-time curves at various stimulus intensities differed only by a velocity factor. 3. During long-lasting constant accelerations the velocity of the head-turning increased to a maximum velocity in a sigmoid time-course and then decreased, first to a constant velocity, and then further. Mean values of the maximum velocity were correlated linearly with the stimulus intensity. 4. It was concluded that the head-turning reflexes in axolotls do not agree with the accepted movements of the vertebrate cupula and therefore are not a simple ‘copy’ of the afferent input. It is also suggested that the reaction threshold differes from that for the labyrinthine input.

Determination of Maleic Hydrazide Residues in Tobacco and Vegetables

1973 ◽  
Vol 56 (5) ◽  
pp. 1164-1172
Author(s):  
Milan Ihnat ◽  
Robert J Westerby ◽  
Israel Hoffman
Keyword(s):  
Standard Deviation ◽  
Present Method ◽  
Maleic Hydrazide ◽  
Collaborative Study ◽  
Official Method ◽  
Sample Weight ◽  
Relative Standard ◽  
The Mean ◽  
Pipe Tobacco

Abstract The distillation-spectrophotometric method of Hoffman for determining maleic hydrazide has been modified to include a double distillation and was applied to the determination of 1–30 ppm maleic hydrazide residues in tobacco and vegetables. Recoveries of 1–23 μg added maleic hydrazide were independent of weight of maleic hydrazide, but did depend on sample and sample weight. The following recoveries were obtained from 0.5 g sample: pipe tobacco, 84%; commercially dehydrated potato, 83%; cigar tobacco, 81%; dried potato, 76%; fluecured tobacco, 73%; dried carrot, 71%. In the absence of sample, the recovery was 82%. When appropriate standard curves were used, maleic hydrazide levels determined in tobacco samples were essentially independent of sample weight in the range 0.1–3 g. The mean relative standard deviation for a variety of field-treated and fortified tobacco samples containing 1–28 ppm maleic hydrazide was 3%. The precision and sensitivity of this procedure seem to be substantial improvements over official method 29.111–29.117. It is recommended that the present method be subjected to a collaborative study.

Discriminable Height Differences of Raised Lines

2020 ◽  
Vol 114 (3) ◽  
pp. 198-211
Author(s):  
Wataru Toyoda ◽  
Ryo Miyamoto ◽  
Susumu Oouchi ◽  
Takenobu Inoue
Keyword(s):  
Older Persons ◽  
Visual Impairments ◽  
Active Touch ◽  
Psychophysical Experiment ◽  
Paired Stimuli ◽  
Main Effect ◽  
Participant Group ◽  
The Mean ◽  
Height Data

Introduction: The purpose of this study was to determine the discriminable height differences of raised lines printed on paper, as assessed by people who are blind, with or without years of tactile experience. Methods: Ten younger and 10 older tactile readers with blindness and with rich tactile experience; and 10 blindfolded, older, sighted participants with little tactile experience discriminated paired raised-line stimuli of different heights using the fingers of their preferred hand by active touch in a psychophysical experiment. Results: There was a significant main effect of the height of the stimulus, F(2, 54) = 56.446, MS = .060, p < .001, [Formula: see text] = .676, [Formula: see text] = .341, and participant group, F(2, 27) = 13.717, MS = .064, p < .001, [Formula: see text] = .504, [Formula: see text] = .357; however, there was no significant main effect of the width of the lines, or any interactions. The younger and older tactile readers had virtually similar thresholds and Weber fractions, and they could discriminate paired stimuli more accurately and efficiently than the older, sighted participants. We provided the discriminable height data of the raised lines based on the mean and 95th percentile values of the Weber fractions. Discussion: The results indicate the importance of tactile experiences for height discrimination in active touch. For older persons with recently developed blindness, raised lines with larger height differences should be used. Information for practitioners: These data will be helpful for developing new braille embossers that can print raised-line graphics for people with visual impairments, with or without years of tactile experience.

Circumferential variation in the relative density of lodgepole pine

1989 ◽  
Vol 19 (2) ◽  
pp. 276-279
Author(s):  
Josefina S. Gonzalez
Keyword(s):  
Relative Density ◽  
Present Method ◽  
Lodgepole Pine ◽  
Breast Height ◽  
Two Samples ◽  
The Mean

The circumferential variation in the wood relative density of lodgepole pine (Pinuscontorta var. latifolia Engelm.) was examined in eight discs taken at breast height. The purpose was to determine if the present method of analyzing two opposite radial strips from pith to bark was sufficient for estimating the mean density of the disc. Results showed that two samples taken opposite each other would give comparable or better approximation of the mean density of the disc than would three or four samples taken at random.

Color difference formulae evaluation by method of adjustment

2014 ◽  
Vol 11 (1) ◽  
pp. 89-94 ◽  
Author(s):  
A. Abbasi ◽  
M. Vik ◽  
M. Vikova
Keyword(s):  
Color Difference ◽  
Psychophysical Method ◽  
Psychophysical Experiment ◽  
Statistical Measures ◽  
Color Differences ◽  
The Mean ◽  
Different Color ◽  
Method Of Adjustment ◽  
Visual Results ◽  
Test Color

This experiment was carried out to test color difference formulae by method of adjustment. 6 different color centers (Red, Yellow, Green, Blue-Green, Blue and Violet) were chosen for this psychophysical experiment. 336 virtual sample pairs were prepared. The mean color difference was three CIELAB units. Each pair was assessed by a panel of 15 observers using psychophysical methods called Method of Adjustment. These visual data were used to test color-difference formulae: CIELAB, CMC, CIE94, DIN99d and CIE2000 with the help of simple statistical measures i.e., PF/3 and Stress. It was found that the visual results obtained from psychophysical method of adjustment show that CIE94 as well as DIN99d still perform well for small color differences.

On using block pulse transform to perform equivalent linearization for a nonlinear Van der Pol oscillator under stochastic excitation

2016 ◽  
Vol 0 (0) ◽  
Author(s):  
Amir Younespour ◽  
Hosein Ghaffarzadeh
Keyword(s):  
Nonlinear System ◽  
Present Method ◽  
Gaussian White Noise ◽  
Van Der Pol Oscillator ◽  
Equivalent Linearization ◽  
Van Der Pol ◽  
White Noise Excitation ◽  
Linearization Methods ◽  
The Mean ◽  
Methods Numerical

AbstractThis paper applied the idea of block pulse (BP) transform in the equivalent linearization of a nonlinear system. The BP transform gives effective tools to approximate complex problems. The main goal of this work is on using BP transform properties in process of linearization. The accuracy of the proposed method compared with the other equivalent linearization including the stochastic equivalent linearization and the regulation linearization methods. Numerical simulations are applied to the nonlinear Van der Pol oscillator system under Gaussian white noise excitation to demonstrate the feasibility of the present method. Different values of nonlinearity are considered to show the effectiveness of the present method. Besides, by comparing the mean-square responses for divers values of nonlinearity and excitation intensity depicted the present method is able to approximate the behavior of nonlinear system and is in agreement with other methods.

Short-Latency Acceleration of Human Heart Rate as a Function of Stimulus Intensity

1977 ◽  
Vol 45 (2) ◽  
pp. 579-583 ◽  
Author(s):  
J. G. O'Gorman ◽  
R. D. Jamieson
Keyword(s):  
Heart Rate ◽  
White Noise ◽  
Stimulus Intensity ◽  
Human Heart ◽  
Short Latency ◽  
Rate Level ◽  
Initial Values ◽  
Heart Rate Level ◽  
The Mean ◽  
Female Subjects

The study examined the effectiveness of three intensities of white noise in evoking short-latency acceleration of human heart rate. 3 groups of 10 female subjects were presented with 1-sec. bursts of white noise with virtually instantaneous rise times at intensities of 100 db (re 20 μN/m2), 90 db, or 80 db SPL as measured at the headset. 5 bursts were presented at intervals of 45 sec. while the EKG was recorded. An increase in heart rate during poststimulus beats 3 and 4 compared with the mean rate of the three beats prestimulus was reliably evoked on the first two trials in the 100-db and 90-db groups but not in the 80-db group. Apart from a recovery of acceleration on Trial 5 for the 100-db group, the 100-db and 90-db groups did not differ in amplitude or rate of habituation of the response. Poststimulus heart-rate level was not significantly related to prestimulus level as expected in terms of the law of initial values. The results were interpreted as consistent with F. K. Graham's interpretation of short-latency cardiac acceleration as a component of startle.

scholarly journals Computerized method for estimation of ultimate load of piles

2018 ◽  
Vol 230 ◽  
pp. 02002
Author(s):  
Basheer Younis ◽  
Khudhair Thamer ◽  
Firas Kazimahomedov
Keyword(s):  
Present Method ◽  
Ultimate Load ◽  
Degree Polynomial ◽  
Maximum Settlement ◽  
Pile Test ◽  
Pile Diameter ◽  
Polynomial Fit ◽  
Pile Settlement ◽  
The Mean ◽  
Test Pile

A new method was established to estimate the ultimate load, which is utilized in the assessment of pile test. In the present study twenty five reports of failure test piles (28.5 x 28.5 cm in dimensions, 12 m in depth and the working load was 40 ton) of Um-Alqura Mosque project were studied in according to their loading and settlement. The (mean ± SD) of the pile settlement for each load of all piles studied were determined, and the results obtained were utilized to generate the equation that correlates between the load and settlement using (4th degree polynomial fit graph). The equation obtained was applied to estimate the ultimate load for the maximum settlement (10% of the pile diameter). The estimated ultimate load (130 ton) in the present study was compared with the ultimate load (132 ton), which was determined previously using (Fellenius and Decourt presentation, 2001). The deviation between the ultimate load of the previous and the present method was (1.5%), but the present method depends on two working load, so it saves time and efforts and suitable to implement in the assessment of the test pile.

An initial test of a method for the estimation of real mean particle size from shadowed samples

1985 ◽  
Vol 31 (7) ◽  
pp. 604-607
Author(s):  
J. H. M. Willison
Keyword(s):  
Particle Size ◽  
Present Method ◽  
Particle Sizes ◽  
Initial Test ◽  
Small Particles ◽  
Mean Particle Size ◽  
Sample Rotation ◽  
Mean Diameter ◽  
The Mean

During shadowing, a "cap" of metal develops on small particles. This cap increases, apparent particle width (measured normal to the shadowing direction) by an extent which cannot be predetermined. The extent of this increase in particle size (here defined as the "cap," X) is estimated in the present method by using opposite (180° sample rotation) bidirectional shadowing. It is argued that the bidirectional cap is the sum of the two unidirectional caps, and therefore that X = 2A − (B + C), where A is the mean bidirectionally shadowed particle size, and B and C are the two mean unidirectionally shadowed particle sizes. As a validation of the method, the mean diameter of air-dried ferritin was estimated and the results appear to confirm the hypothesis (mean diameter by present method, 10.7 ± 0.2 nm; mean diameter by previous methods, 10.89 nm).

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