Meridional Differences in Temporal Resolution

Perception ◽  
1982 ◽  
Vol 11 (1) ◽  
pp. 25-34 ◽  
Author(s):  
Barry D Schwartz ◽  
Daniel K Winstead ◽  
James G May
Keyword(s):  
Spatial Frequency ◽  
Temporal Resolution ◽  
Oblique Effect ◽  
Channel Activity ◽  
Flash Duration ◽  
Choice Procedure ◽  
Stimulus Parameters ◽  
Transient Activity ◽  
Transient Channel ◽  
Forced Choice Procedure

Previous investigations of temporal resolution have shown that performance is influenced by a number of stimulus parameters. The interstimulus interval needed for accurate two-pulse discrimination has been shown to (i) decrease monotonically with flash duration, luminance, and contrast; and (ii) increase monotonically with the spatial frequency of the target. A signal-detectability two-alternative forced-choice procedure was employed to reexamine the effects of spatial frequency on temporal resolution. Also assessed was the effect of grating orientation on such performance. The results confirm that temporal resolution declines with increases in spatial frequency. Furthermore, temporal resolution was significantly lower when oblique, as opposed to vertical, grating targets were used. This ‘oblique effect’ in temporal resolution was observed only with the highest-spatial-frequency target (15 cycles deg−1), and not with stimuli of lower spatial frequency (0·9 and 3·8 cycles deg−1). These findings suggest that stimulus parameters which elicit greater transient channel activity, as opposed to sustained channel activity, enhance temporal resolution. When transient activity is at a minimum, meridional differences in temporal resolution are likely to be attributable to sustained channel activity.

Reaction Time to Gratings: A Re-Examination

Perception ◽  
1996 ◽  
Vol 25 (1_suppl) ◽  
pp. 16-16 ◽  
Author(s):  
C Bonnet ◽  
J P Thomas ◽  
P Fagerholm
Keyword(s):  
Reaction Time ◽  
Spatial Frequency ◽  
Window Size ◽  
Vertical Axis ◽  
Grating Period ◽  
Sinusoidal Grating ◽  
Choice Procedure ◽  
Frequency Detection ◽  
Forced Choice Procedure ◽  
Number Of Cycles

We have examined the relationship between the reaction time for detecting a sinusoidal grating stimulus and the stimulus variables of spatial frequency, contrast, window size, and uncertainty with respect to spatial frequency. Detection was measured in a two-alternative spatial-forced-choice procedure. The stimuli were horizontal cosine gratings windowed spatially by two-dimensional Gaussians. Spatial frequency was varied from 0.7 to 6.5 cycles deg−1 and contrast was varied from 0.054 to 0.673. The standard deviation of the Gaussian window was fixed in some conditions and the number of cycles presented in each window covaried with spatial frequency. In other conditions, window size was varied, along the vertical axis only, to hold the number of cycles constant. Contrasts were always randomly intermixed, but frequencies were intermixed in some conditions and blocked in others. We confirm previous findings that reaction time increases as spatial frequency increases and decreases as contrast increases. We also confirm and extend the proposal of Rudd that reaction time closely approximates a single function of the product of contrast and the square of the grating period. We consider the implications of these findings for the nature of the physiological mechanisms which govern reaction time.

The Sensitivity of Binocular Rivalry Suppression to Changes in Orientation Assessed by Reaction-Time and Forced-Choice Techniques

Perception ◽  
1981 ◽  
Vol 10 (3) ◽  
pp. 283-293 ◽  
Author(s):  
Robert P O'Shea ◽  
Boris Crassini
Keyword(s):  
Reaction Time ◽  
Spatial Frequency ◽  
Binocular Rivalry ◽  
Luminance Contrast ◽  
Forced Choice ◽  
Field Size ◽  
Correct Performance ◽  
Orientation Change ◽  
Choice Procedure ◽  
Forced Choice Procedure

Binocular rivalry was induced between two orthogonal square-wave gratings of the same spatial frequency, luminance, contrast, and field size, presented dichoptically. One of the gratings could be instantly replaced by a third grating differing only in orientation. In one experiment subjects were required to respond as soon as an orientation change was noticed, and to withold response to catch trials (no orientation change). When orientation changes were made to the visible grating, reaction time was found to be a U-shaped function of the magnitude of orientation change. When orientation changes were made to the grating undergoing binocular-rivalry suppression, an overall increase in reaction time was found with the increase being greater for large orientation changes (an asymmetrical U-shaped function). In another experiment subjects were required to detect the direction of a change in orientation in a two-alternative forced-choice procedure. Thresholds were thus obtained for 75% correct performance. It was found that thresholds for orientation changes made to the visible and invisible fields were identical from 20° to 70° orientation change. Outside this range thresholds were higher when orientation changes were made to the field suppressed by binocular rivalry. It is argued that the orientation functions obtained in the two experiments may represent incomplete suppression of either form or transient information during binocular rivalry.

scholarly journals ‘The last channel’: vision at the temporal margin of the field

2020 ◽  
Vol 287 (1927) ◽  
pp. 20200607
Author(s):  
P. Veto ◽  
P. B. M. Thomas ◽  
P. Alexander ◽  
T. A. Wemyss ◽  
J. D. Mollon
Keyword(s):  
Individual Differences ◽  
Eye Movements ◽  
Visual Field ◽  
Spatial Frequency ◽  
High Density ◽  
Line Of Sight ◽  
Histological Evidence ◽  
Choice Procedure ◽  
Forced Choice Procedure ◽  
Temporal Side

The human visual field, on the temporal side, extends to at least 90° from the line of sight. Using a two-alternative forced-choice procedure in which observers are asked to report the direction of motion of a Gabor patch, and taking precautions to exclude unconscious eye movements in the direction of the stimulus, we show that the limiting eccentricity of image-forming vision can be established with precision. There are large, but reliable, individual differences in the limiting eccentricity. The limiting eccentricity exhibits a dependence on log contrast; but it is not reduced when the modulation visible to the rods is attenuated, a result compatible with the histological evidence that the outermost part of the retina exhibits a high density of cones. Our working hypothesis is that only one type of neural channel is present in the far periphery of the retina, a channel that responds to temporally modulated stimuli of low spatial frequency and that is directionally selective.

Effect of Luminance Contrast on the Motion Aftereffect

Perception ◽  
1997 ◽  
Vol 26 (1_suppl) ◽  
pp. 191-191
Author(s):  
M Ishihara
Keyword(s):  
Spatial Frequency ◽  
Motion Aftereffect ◽  
Luminance Contrast ◽  
Sinusoidal Grating ◽  
Channel Activity ◽  
High Luminance ◽  
Frequency Condition ◽  
Parvocellular Pathway ◽  
Low Luminance ◽  
Transient Channel

The effects of luminance contrast and spatial frequency in the transient channel were investigated by making use of the motion aftereffect (MAE) caused by adaptation to a drifting sinusoidal grating. Two experiments were performed. The PSE of the velocity was measured as an index of the MAE. The adapting grating was made to drift at a velocity of 2.28 deg s−1 and its spatial frequency was 0.8, 1.6, or 3.2 cycles deg−1. In the first experiment, the MAE caused by a luminance contrast grating or an equiluminous chromatic grating was measured. In the second experiment, luminance contrast gratings were used to measure the effect of the contrast differences between adapting and test gratings. The largest MAE was observed when a low-luminance-contrast grating or an equiluminous chromatic grating was presented as test stimulus after adaptation to a high-luminance-contrast grating in the low-spatial-frequency condition. Generally, the MAE increased with increasing adapting contrast and with decreasing test contrast or spatial frequency. Little MAE was observed at high test contrasts. The results may be explained by assuming that activity in the sustained channel (or parvocellular pathway) inhibits activity in the transient channel (or magnocellular pathway) owing to the domination of sustained channel activity when the test is a static high-luminance-contrast grating providing much information about position and form.

scholarly journals High Ripple-Density Resolution for Discriminating Between Rippled and Nonrippled Signals: Effect of Temporal Processing or Combination Products?

2021 ◽  
Vol 25 ◽  
pp. 233121652110101
Author(s):  
Dmitry I. Nechaev ◽  
Olga N. Milekhina ◽  
Marina S. Tomozova ◽  
Alexander Y. Supin
Keyword(s):  
Low Frequency ◽  
Noise Signal ◽  
Density Variation ◽  
Choice Procedure ◽  
Masker Level ◽  
Reference Signals ◽  
Forced Choice Procedure ◽  
The Mean ◽  
Density Resolution

The goal of the study was to investigate the role of combination products in the higher ripple-density resolution estimates obtained by discrimination between a spectrally rippled and a nonrippled noise signal than that obtained by discrimination between two rippled signals. To attain this goal, a noise band was used to mask the frequency band of expected low-frequency combination products. A three-alternative forced-choice procedure with adaptive ripple-density variation was used. The mean background (unmasked) ripple-density resolution was 9.8 ripples/oct for rippled reference signals and 21.8 ripples/oct for nonrippled reference signals. Low-frequency maskers reduced the ripple-density resolution. For masker levels from −10 to 10 dB re. signal, the ripple-density resolution for nonrippled reference signals was approximately twice as high as that for rippled reference signals. At a masker level as high as 20 dB re. signal, the ripple-density resolution decreased in both discrimination tasks. This result leads to the conclusion that low-frequency combination products are not responsible for the task-dependent difference in ripple-density resolution estimates.

Age Effects on Measures of Auditory Duration Discrimination

1994 ◽  
Vol 37 (3) ◽  
pp. 662-670 ◽  
Author(s):  
Peter J. Fitzgibbons ◽  
Sandra Gordon-Salant
Keyword(s):  
Hearing Loss ◽  
Stimulus Frequency ◽  
The Elderly ◽  
Duration Discrimination ◽  
Elderly Subjects ◽  
Hearing Sensitivity ◽  
Choice Procedure ◽  
Forced Choice Procedure ◽  
Tonal Stimuli ◽  
Young And Elderly Subjects

This study examined auditory temporal sensitivity in young adult and elderly listeners using psychophysical tasks that measured duration discrimination. Listeners in the experiments were divided into groups of young and elderly subjects with normal hearing sensitivity and with mild-to-moderate sloping sensorineural hearing loss. Temporal thresholds in all tasks were measured with an adaptive forced-choice procedure using tonal stimuli centered at 500 Hz and 4000 Hz. Difference limens for duration were measured for tone bursts (250 msec reference duration) and for silent intervals between tone bursts (250 msec and 6.4 msec reference durations). Results showed that the elderly listeners exhibited diminished duration discrimination for both tones and silent intervals when the reference duration was 250 msec. Hearing loss did not affect these results. Discrimination of the brief temporal gap (6.4 msec) was influenced by age and hearing loss, but these effects were not consistent across all listeners. Effects of stimulus frequency were not evident for most of the duration discrimination conditions.

scholarly journals A Forced-Choice Procedure to Assess the Acute Relative Reinforcing Effects of Nicotine Dose per se in Humans

2019 ◽  
Vol 22 (10) ◽  
pp. 1685-1693 ◽  
Author(s):  
Kenneth A Perkins ◽  
Joshua L Karelitz
Keyword(s):  
A Priori ◽  
Fixed Number ◽  
Forced Choice ◽  
Choice Procedure ◽  
Novel Drugs ◽  
Reinforcing Value ◽  
Forced Choice Procedure ◽  
Per Se ◽  
Reinforcing Effects ◽  
Study Participants

Abstract Introduction A method to assess acute reinforcement due to nicotine may aid identification of doses needed to maintain dependence. After describing development of a forced-choice procedure, results are presented from two studies using it to determine the relative reinforcing effects of nicotine dose per se. Aims and Methods Choice between a higher versus a very low or no nicotine option, via smoking (Study 1, n = 59) and via nasal spray (Study 2, n = 42), was assessed in nontreatment-seeking dependent smokers abstinent overnight. Using a within-subject design, different nicotine levels for each product were administered under blind conditions, initially to assess their discriminability (Study 1: 1.3–17 mg/g each vs. 0.4 mg/g nicotine Spectrum cigarettes; Study 2: 2.5 µg/kg vs. 0 µg/kg nicotine per spray). At the end of sessions for each study, participants engaged in forced-choice trials to assess preference, requiring a fixed number of puffs/sprays for one and/or the other. Results Confirming the procedure’s validity, the choice of the higher nicotine option was significantly greater than that for the very low or no nicotine option in both studies. In Study 1, choice relative to 0.4 mg/g was greater for cigarettes 5.3 mg/g or more but not 2.3 mg/g or less (p = .003 for the interaction of higher content vs. 0.4 mg/g comparison). In Study 2, choice was greater for the nicotine versus placebo spray (p < .005), as nicotine was preferred nearly twice as much as the placebo. Conclusion This forced-choice procedure may efficiently determine the relative reinforcing value of a nicotine dose per se. Implications The forced-choice procedure described here may identify nicotine doses that are acutely reinforcing in dependent smokers. A priori research of choice comparisons between small versus zero nicotine doses could inform clinical research in larger and more diverse samples to determine nicotine contents in cigarettes, and perhaps in other commercial products, that are not reinforcing and, thus, likely to reduce the risk of their addictiveness. This procedure may also be applicable to assessing changes in acute nicotine reinforcement due to different product formulations, novel drugs, or other manipulations, perhaps helping inform development of new interventions for cessation or harm reduction.

scholarly journals Children’s understanding of inherited resemblance: The case of two parents

2003 ◽  
Vol 27 (4) ◽  
pp. 366-374 ◽  
Author(s):  
Mark Meerum Terwogt ◽  
Hedy Stegge ◽  
Carolien Rieffe
Keyword(s):  
Forced Choice ◽  
Physical Characteristics ◽  
Parent Child Relationship ◽  
Additional Information ◽  
Choice Procedure ◽  
Child Relationship ◽  
Biological Parents ◽  
Forced Choice Procedure ◽  
Parent Child

Four-, 6-, and 10-year-old children were tested in a forced-choice procedure about their beliefs on the inheritance of physical characteristics. They were presented with pictures of two biological parents, and then asked to select the most likely descendant out of three alternatives: a father look-alike, a mother look-alike, and an alternative representing the combined influence of both parents. In several question pairs, additional information was given about the parent–child relationship that was clearly irrelevant to the principles of heredity to examine the extent to which domain confusions were likely to occur. The majority of the 10-year-olds consistently preferred the alternative in which the combined influence of both parents was shown and domain confusions hardly ever occurred. Four- and 6-year-olds, in contrast, were still influenced by information from alien domains, although even their reasoning about inheritance seemed to be theory-like. Overall, the results suggest that with age, children develop a more restricted and better-defined conception of the principles of heredity, in which the combined influence of both parents is acknowledged.

scholarly journals Comparing Rapid and Traditional Forward-Masked Spatial Tuning Curves in Cochlear-Implant Users

2019 ◽  
Vol 23 ◽  
pp. 233121651985130
Author(s):  
Heather A. Kreft ◽  
Lindsay A. DeVries ◽  
Julie G. Arenberg ◽  
Andrew J. Oxenham
Keyword(s):  
Cochlear Implant ◽  
Tuning Curve ◽  
Measurement Procedure ◽  
Forced Choice ◽  
Adaptive Procedure ◽  
Tuning Curves ◽  
Choice Procedure ◽  
Spatial Tuning ◽  
Forced Choice Procedure ◽  
Test Retest Reliability

A rapid forward-masked spatial tuning curve measurement procedure, based on Bekesy tracking, was adapted and evaluated for use with cochlear implants. Twelve postlingually-deafened adult cochlear-implant users participated. Spatial tuning curves using the new procedure and using a traditional forced-choice adaptive procedure resulted in similar estimates of parameters. The Bekesy-tracking method was almost 3 times faster than the forced-choice procedure, but its test–retest reliability was significantly poorer. Although too time-consuming for general clinical use, the new method may have some benefits in individual cases, where identifying electrodes with poor spatial selectivity as candidates for deactivation is deemed necessary.

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