Signal detection, choice response times, and visual backward masking.

1965 ◽  
Vol 19 (2) ◽  
pp. 118-132 ◽  
Author(s):  
Robert W. Sekuler
Keyword(s):  
Signal Detection ◽  
Response Times ◽  
Choice Response ◽  
Backward Masking ◽  
Visual Backward Masking

Effect of Practice on Visual Backward Masking

1980 ◽  
Vol 50 (2) ◽  
pp. 511-517
Author(s):  
David Braff ◽  
Dennis Saccuzzo ◽  
Rick Ingram ◽  
Brian Mc Neill ◽  
Richard Langford
Keyword(s):  
Signal Detection ◽  
Stimulus Duration ◽  
Target Stimulus ◽  
Practice Effects ◽  
Backward Masking ◽  
Considerable Variability ◽  
Pattern Mask ◽  
Critical Stimulus ◽  
Visual Backward Masking ◽  
Made In

Five experiments studied practice effects for 4, 7, 11 subjects on visual backward masking using a signal-detection procedure under various conditions. Exp. I determined the minimum perceptible critical stimulus duration (CSD) for criterion identification of a target stimulus, the letter T or A. In Exp. II, the stimulus was presented at the critical stimulus duration (CSD) followed by a pattern mask at intervals of 20 to 120 msec. for 15 separate sessions. In Exp. III ( N = 4) the mask followed the CSD in intervals of 2-msec. increments until subjects reached criterion accuracy. Exps. IV and V ( Ns = 4, 7) provided partial replications of Exps. II and III. Naive subjects were used, and the stimulus duration was constant for all subjects. When masking functions were obtained at a threshold, considerable variability was found and subjects improve slowly or not at all over sessions. With a fixed suprathreshold stimulus, all subjects improve with practice. The importance of these findings is discussed as they relate to common (and largely untested) assumptions made in the backward masking and perception literature.

Patients with functional psychoses show similar visual backward masking deficits

2012 ◽  
Vol 198 (2) ◽  
pp. 235-240 ◽  
Author(s):  
Eka Chkonia ◽  
Maya Roinishvili ◽  
Liza Reichard ◽  
Wenke Wurch ◽  
Hendrik Puhlmann ◽  
...  
Keyword(s):  
Backward Masking ◽  
Functional Psychoses ◽  
Visual Backward Masking

scholarly journals The roles of mask luminance and perceptual grouping in visual backward masking

2009 ◽  
Vol 9 (11) ◽  
pp. 22-22 ◽  
Author(s):  
I. Dombrowe ◽  
F. Hermens ◽  
G. Francis ◽  
M. H. Herzog
Keyword(s):  
Perceptual Grouping ◽  
Backward Masking ◽  
Visual Backward Masking

scholarly journals Electrophysiological correlates of visual backward masking in patients with first episode psychosis

2018 ◽  
Vol 282 ◽  
pp. 64-72 ◽  
Author(s):  
Ophélie Favrod ◽  
Maya Roinishvili ◽  
Janir R. da Cruz ◽  
Andreas Brand ◽  
Mariam Okruashvili ◽  
...  
Keyword(s):  
First Episode Psychosis ◽  
First Episode ◽  
Backward Masking ◽  
Episode Psychosis ◽  
Visual Backward Masking

scholarly journals Combining vernier acuity and visual backward masking as a sensitive test for visual temporal deficits in aging research

2011 ◽  
Vol 51 (4) ◽  
pp. 417-423 ◽  
Author(s):  
Maya Roinishvili ◽  
Eka Chkonia ◽  
Andrea Stroux ◽  
Andreas Brand ◽  
Michael H. Herzog
Keyword(s):  
Sensitive Test ◽  
Backward Masking ◽  
Vernier Acuity ◽  
Aging Research ◽  
Visual Backward Masking

1.2 Method of constant stimuli (Method of frequency) By the Method of Frequency the stimulus range is selected in discrete intervals so that the frequency of positive answers is distributed over the range between 1% and 99%. In general, the frequency of positive res­ ponses either for an individual or for a group, is cumulatively normally distributed over a geometric intensity continuum. The absolute odor thre­ shold can then be defined as the effective dose corresponding to an arbi­ trarily selected frequency of positive responses, ordinarily 50% : ED^: Effective dose at the 50% level. 3.1.3 Signal detection The Signal Detection principle is a determination of the relation­ ship between hits and false alarms. In determining signal detectability, a stimulus or a few stimuli are presented in random order, alternating with noise. Since sensory impressions resulting frcm the presentation of stimulus versus noise are assumed to be normally distributed over the same intensity continuum and to have the same dispersion, the index of detectability d' for p (hits) minus p (false) indicates the extent to which the two distributions overlap. 3.2 Indication of response 3.2.1 "Yes" or "no" response In the classical evaluation yes-no answers are dependent on the sub­ jects1 honesty and motivation among other factors. However, yes-no ans­ wers may be evaluated if they are presented a sufficiently large number of times alternating with blanks. 3.2.2 forced choice technique One method of controlling response perseveration and otter antici­ pation factors is to use a forced choice response indication based on two or more response categories. In the measurement of odors the panelist has to report the temporal position of positive stimuli in a series of randan blanks. If the concentration is below the threshold, the test sub­ jects will guess. As the odorant concentration will increase, the rela­ tive cumulative frequency for identification of the correct sample will be greater. In order to determine the relative odor recognition a cor­ rection must be made. 3.3 Size of stimulus intervals 3.3.1 Concentration intervals In selecting the stimulus continuum in threshold determination, the relation between just noticeable difference in relation to the intensity of stimuli is of interest. In accordance with Weber's law this quotient is assumed to be a constant. Therefore it would appear best to determine absolute thresholds on an intensity continuum in the form of a gecxnetric progression. 3.2.2 Time intervals Because of adaptation processes the exposure time until reaching a decision should be limited. Also the interval between two stimuli must be observed.

1986 ◽  
pp. 71-71
Keyword(s):  
Signal Detection ◽  
Effective Dose ◽  
Random Order ◽  
Stimulus Range ◽  
Forced Choice ◽  
Just Noticeable Difference ◽  
False Alarms ◽  
Choice Response ◽  
Temporal Position ◽  
Normally Distributed

scholarly journals Electrophysiological correlates of visual backward masking in patients with bipolar disorder

2020 ◽  
Author(s):  
Simona Garobbio ◽  
Maya Roinishvili ◽  
Ophélie Favrod ◽  
Janir Ramos da Cruz ◽  
Eka Chkonia ◽  
...  
Keyword(s):  
Bipolar Disorder ◽  
Global Field ◽  
Target Onset ◽  
Backward Masking ◽  
Global Field Power ◽  
Functional Psychoses ◽  
Visual Backward Masking

AbstractBackgroundIn visual backward masking (VBM), a target is followed by a mask that decreases target discriminability. Schizophrenia patients (SZ) show strong and reproducible masking impairments, which are associated with reduced EEG amplitudes. Patients with bipolar disorder (BP) show masking deficits, too. Here, we investigated the neural EEG correlates of VBM in BP.Methods122 SZ, 94 unaffected controls, and 38 BP joined a standard VBM experiment. 123 SZ, 94 unaffected controls and 16 BP joined a corresponding EEG experiment, analyzed in terms of the global field power.ResultsAs in previous studies, SZ and BP show strong masking deficits. Importantly and similarly to SZ, BP show decreased global field power amplitudes at approximately 200 ms after the target onset, compared to controls.ConclusionsThese results suggest that VBM deficits are not specific for schizophrenia but for a broader range of functional psychoses. Potentially, both SZ and BP show deficient target enhancement.

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