Speed Judgments of Transparent Stimuli

Perception ◽  
1996 ◽  
Vol 25 (1_suppl) ◽  
pp. 107-107
Author(s):  
J B Mulligan
Keyword(s):  
Test Pattern ◽  
Random Noise ◽  
Discrimination Performance ◽  
Mask Condition ◽  
Mask Pattern ◽  
Standard Pattern ◽  
Band Pass ◽  
Speed Discrimination ◽  
Moving Patterns ◽  
Direction Opposite

When two moving patterns are combined additively, observers often perceive two transparent surfaces, even when there are no cues supporting this segmentation in a frozen snapshot. The ability of observers to make quantitative judgments about the speed of one of the patterns under these conditions was examined. The component patterns consisted of band-pass-filtered random noise presented in a spatial Gaussian contrast envelope, displayed for 250 ms. On each trial a standard pattern appeared on one side of the fixation point, while a test pattern appeared on the other. The test pattern moved in the same direction as the standard, but with a speed which varied from trial to trial according to a staircase procedure. The subjects' task was to report the side of the fixation point on which faster motion was seen. In some conditions the test stimulus was made to appear transparent by adding a mask pattern. When the mask was stationary, or moved slowly with respect to the test, no significant biases were introduced and discrimination performance was comparable to the no-mask condition (typically 3%). But if the mask moved over the test with similar speed, the task became much harder, regardless of whether the mask moved in a direction opposite or orthogonal to the test. (Some subjects commented on a perceived directional repulsion between tests and orthogonally moving masks.) These results suggest the use of nondirectional temporal channels in the performance of the speed discrimination task.

The Effect of Stationary Patterns on Adaptation for Movement: Evidence for Inhibitory Interaction

Perception ◽  
1975 ◽  
Vol 4 (3) ◽  
pp. 311-329 ◽  
Author(s):  
John E W Mayhew
Keyword(s):  
Test Pattern ◽  
Threshold Elevation ◽  
Inhibitory Interaction ◽  
Movement Aftereffect ◽  
Specific Adaptation ◽  
Neural Processes ◽  
Stationary Test ◽  
Simple Movement ◽  
Moving Patterns ◽  
Moving Pattern

Contingent movement aftereffects (CMAEs) can be demonstrated by adapting to a red pattern rotating clockwise (cw) alternating with a green pattern rotating counterclockwise (ccw). After 5 min subjects typically report stationary test patterns as apparently rotating clockwise when they are green and counterclockwise when they are red. Also, luminance thresholds for motion now depend on both the colour and direction of the moving pattern. The thresholds for red—cw and green—ccw motion will be relatively greater than for the opposite colour motion pairings. This is called contingent threshold elevation. When stationary dots the same colour as the moving patterns are added to the adapting stimuli, subjects report weak CMAEs but no contingent threshold elevation can be demonstrated. When stationary dots opposite in colour to the moving patterns are added to the adapting stimuli, neither CMAEs nor contingent threshold elevation can be demonstrated. And yet colour specific adaptation does occur, and can be demonstrated in the colour specificity of the simple movement aftereffect. When stationary dots are added to the adapting pattern, the simple movement aftereffect though reduced, is greatest on a test pattern of the same colour as the moving dots. These findings suggest that the CMAE, contingent threshold elevation, and the colour specificity of the movement aftereffect involves neural processes differentially sensitive to the presence of stationary patterns.

Neural response to the second stimulus associated with poor speed discrimination performance in schizophrenia

2011 ◽  
Vol 49 (2) ◽  
pp. 198-206 ◽  
Author(s):  
Jun Wang ◽  
Karen R. Dobkins ◽  
Jennifer E. McDowell ◽  
Brett A. Clementz
Keyword(s):  
Discrimination Performance ◽  
Neural Response ◽  
Speed Discrimination

Comparative Evaluation of the Auditory Responsiveness of Normal Infants and Profoundly Multihandicapped Children

1985 ◽  
Vol 28 (2) ◽  
pp. 163-168 ◽  
Author(s):  
Carol Flexer ◽  
Donald P. Gans
Keyword(s):  
Comparative Evaluation ◽  
Random Noise ◽  
The Other ◽  
Hearing Level ◽  
Confidence Levels ◽  
Developmental Age ◽  
Developmental Scale ◽  
Band Pass ◽  
The Subject

Responses to sound were observed in two groups of children. One was developmentally normal; the other was older but profoundly multihandicapped. The groups had developmental ages from 2 to 4 months, as assessed by the Kent Infant Developmental Scale (Katoff, Reuter, & Dunn, 1978). Stimuli were speech and random noise, both unfiltered and band-pass filtered at 2000 Hz, presented at 40, 60, and 80 dB HL. Responsiveness was determined from the confidence levels of observers' judgments of videotapes. Results showed that there were no significant differences between the subject groups. In both groups, however, responsiveness was dependent on hearing level and bandwidth but not on meaningfulness. The results support the practice of evaluating auditory responsiveness of multihandicapped children in relation to developmental age.

Aging and the Perception of Speed

Perception ◽  
10.1068/p3478 ◽  
2003 ◽  
Vol 32 (1) ◽  
pp. 85-96 ◽  
Author(s):  
J Farley Norman ◽  
Heather E Ross ◽  
Laura M Hawkes ◽  
Jennifer R Long
Keyword(s):  
Discrimination Performance ◽  
Significant Deterioration ◽  
Speed Difference ◽  
Moving Stimulus ◽  
Difference Thresholds ◽  
Effects Of Aging ◽  
Moving Patterns

Two experiments were conducted to explore the potential effects of aging upon the perception and discrimination of speed. In the first experiment, speed difference thresholds were obtained for younger and older observers for a variety of standard speeds ranging from slow to fast. The second experiment was designed to evaluate the observers' ability to discriminate differences in the speed of moving patterns in the presence of significant amounts of noise (the noise was manipulated by limiting the lifetimes of individual moving stimulus elements). The results of both experiments revealed a significant deterioration in the ability of the older observers to perceive or detect differences in speed. While the presence of noise was found to affect the observers' discrimination performance, it affected both younger and older observers' thresholds in a proportionally equivalent manner—the older observers were no more affected by noise than the younger observers.

scholarly journals Low-Voltage Low-Pass and Band-Pass Elliptic Filters Based on Log-Domain Approach Suitable for Biosensors

Sensors ◽  
2019 ◽  
Vol 19 (24) ◽  
pp. 5581
Author(s):  
Pipat Prommee ◽  
Natapong Wongprommoon ◽  
Montree Kumngern ◽  
Winai Jaikla
Keyword(s):  
Low Voltage ◽  
Random Noise ◽  
Low Frequency ◽  
Frequency Noise ◽  
Bipolar Junction Transistor ◽  
Low Pass ◽  
Junction Transistor ◽  
Band Pass ◽  
Electronically Tunable ◽  
Log Domain

This research proposes bipolar junction transistor (BJT)-based log-domain high-order elliptic ladder low-pass (LPF) and band-pass filters (BPF) using a lossless differentiator and lossless and lossy integrators. The log-domain lossless differentiator was realized by using seven BJTs and one grounded capacitor, the lossy integrator using five BJTs and one grounded capacitor, and the lossless integrator using seven BJTs and one grounded capacitor. The simplified signal flow graph (SFG) of the elliptic ladder LPF consisted of two lossy integrators, one lossless integrator, and one lossless differentiator, while that of the elliptic ladder BPF contained two lossy integrators, five lossless integrators, and one lossless differentiator. Log-domain cells were directly incorporated into the simplified SFGs. Simulations were carried out using PSpice with transistor array HFA3127. The proposed filters are operable in a low-voltage environment and are suitable for mobile equipment and further integration. The log-domain principle enables the frequency responses of the filters to be electronically tunable between 10k Hz–10 MHz. The proposed filters are applicable for low-frequency biosensors by reconfiguring certain capacitors. The filters can efficiently remove low-frequency noise and random noise in the electrocardiogram (ECG) signal.

scholarly journals Speed discrimination performance in adults but not children correlates with single-word reading rate

2012 ◽  
Vol 12 (9) ◽  
pp. 764-764
Author(s):  
F. Pestilli ◽  
K. Main ◽  
J. Yeatman ◽  
A. Mezer ◽  
R. Martin ◽  
...  
Keyword(s):  
Word Reading ◽  
Discrimination Performance ◽  
Reading Rate ◽  
Single Word ◽  
Speed Discrimination ◽  
Single Word Reading

Transformation of Stimulus Information from Very Short-Term Memory

1977 ◽  
Vol 44 (3) ◽  
pp. 951-958
Author(s):  
Helen Altman Klein
Keyword(s):  
Stimulus Pattern ◽  
Test Pattern ◽  
Short Term Memory ◽  
Response Selection ◽  
Mask Pattern ◽  
Short Term ◽  
Initial Stimulus ◽  
Term Memory ◽  
Response Data ◽  
Input Processing

Observers were shown a simple stimulus pattern, a mask pattern, and a test pattern on each trial. Different types of test patterns were used to assess transformations of material from very short-term memory. The durations of the initial stimulus pattern and the mask pattern were also varied. Significant differences in average response data were found between types of test pattern over exposure durations; however, sensitivity measures showed minimal differences between types of test pattern. This suggested some distinctions between input processing and response selection in the paradigm. Selective feature analysis seems to be a characteristic of response selection.

scholarly journals Auditory speed processing in sighted and blind individuals

PLoS ONE ◽  
2021 ◽  
Vol 16 (9) ◽  
pp. e0257676
Author(s):  
Giorgia Bertonati ◽  
Maria Bianca Amadeo ◽  
Claudio Campus ◽  
Monica Gori
Keyword(s):  
Visual Experience ◽  
Discrimination Performance ◽  
Temporal Cues ◽  
Stimulus Speed ◽  
Sensory Modalities ◽  
Speed Perception ◽  
Speed Discrimination ◽  
The Time Domain ◽  
Blind Individuals ◽  
The Relationship

Multisensory experience is crucial for developing a coherent perception of the world. In this context, vision and audition are essential tools to scaffold spatial and temporal representations, respectively. Since speed encompasses both space and time, investigating this dimension in blindness allows deepening the relationship between sensory modalities and the two representation domains. In the present study, we hypothesized that visual deprivation influences the use of spatial and temporal cues underlying acoustic speed perception. To this end, ten early blind and ten blindfolded sighted participants performed a speed discrimination task in which spatial, temporal, or both cues were available to infer moving sounds’ velocity. The results indicated that both sighted and early blind participants preferentially relied on temporal cues to determine stimuli speed, by following an assumption that identified as faster those sounds with a shorter duration. However, in some cases, this temporal assumption produces a misperception of the stimulus speed that negatively affected participants’ performance. Interestingly, early blind participants were more influenced by this misleading temporal assumption than sighted controls, resulting in a stronger impairment in the speed discrimination performance. These findings demonstrate that the absence of visual experience in early life increases the auditory system’s preference for the time domain and, consequentially, affects the perception of speed through audition.

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