scholarly journals Photic facilitation of tonal signal detection in a forced-choice situation

1966 ◽  
Vol 6 (10) ◽  
pp. 477-478 ◽  
Author(s):  
William H. Watkins
Keyword(s):  
Signal Detection ◽  
Forced Choice ◽  
Choice Situation ◽  
Tonal Signal ◽  
Tonal Signal Detection

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 Behavioral and EEG reactions in primary school-aged children to emotionally colored verbal stimuli with the condition of their own or forced choice

2017 ◽  
Vol 8 (4) ◽  
pp. 72-90 ◽  
Author(s):  
T.A. Aiusheeva ◽  
A.E. Saprygin ◽  
A.N. Savostyanov ◽  
V.V. Stеpanova
Keyword(s):  
Primary School ◽  
Positive Emotions ◽  
Alpha Rhythm ◽  
Spectral Power ◽  
Forced Choice ◽  
Choice Situation ◽  
Verbal Stimuli ◽  
School Aged Children ◽  
Theta Range

The aim of the study is to compare behavioral and EEG reactions of primary school-aged children during the recognition of syntactic errors in emotionally (positively or negatively) colored sentences that appeal to the choice of the child differently. 20 children (mean age 9,0±0,3 years, 12 boys, 8 girls) were examined. We found out that the children with a high quality of solving a linguistic task concentrate all their attention on finding an error in the sentences, and children with a low quality of solving a task demonstrate increased emotionality, possibly connected with their unsuccessfulness. The strongest EEG reactions in the ranges of alpha- and theta- rhythms were recorded in children with slow speed and bad quality of the solution of the task. The recognition of sentences with negative emotions took longer than sentences with positive emotions. The increase of emotions (synchronization in theta range) during the recognition of negative sentences was provoked by the expectation of failure and “identification” with it. The children found the mistake better in the sentences with their own choice than in the sentences that describes the forced-choice situation. Desynchronization (i.e. decrease in the spectral power) and synchronization (i.e. increase in spectral power) was detected on the EEG in the alpha-rhythm range. Desynchronization was associated with the recognition of sentences describing the children’s own choice; synchronization was recorded when recognizing sentences describing the forced-choice situation.

scholarly journals Bias effects in a two-stage recognition paradigm: A challenge for ‘pure’ threshold and signal detection models

2021 ◽  
Author(s):  
Qiuli Ma ◽  
Jeffrey Joseph Starns ◽  
David Kellen
Keyword(s):  
Signal Detection ◽  
Forced Choice ◽  
Dual Process ◽  
High Threshold ◽  
Word Target ◽  
Choice Data ◽  
Two Stage ◽  
Unequal Variance ◽  
Single Item

We explored a two-stage recognition memory paradigm in which people first make single-item “studied”/“not studied” decisions and then have a chance to correct their errors in forced-choice trials. Each forced-choice trial included one studied word (“target”) and one non-studied word (“lure”) that received the same previous single-item response. For example, a “studied”-“studied” trial would have a target that was correctly called “studied” and a lure that was incorrectly called “studied.” The two-high-threshold (2HT) model and the unequal-variance signal detection (UVSD) model predict opposite effects of biasing the initial single-item responses on subsequent forced-choice accuracy. Results from two experiments showed that the bias effect is actually near zero and well out of the range of effects predicted by either model. Follow-up analyses showed that the model failures were not a function of experiment artifacts like changing memory states between the two types of recognition trials. Follow-up analyses also showed that the dual process signal detection (DPSD) model made better predictions for the forced-choice data than 2HT and UVSD models.

Two-Pulse Temporal Integration Functions in the Fovea and Peripheral Retina

1987 ◽  
Vol 64 (2) ◽  
pp. 343-354 ◽  
Author(s):  
Michael D. Gottlieb ◽  
Mitchell L. Kietzman
Keyword(s):  
Signal Detection ◽  
Temporal Integration ◽  
Forced Choice ◽  
Critical Duration ◽  
Peripheral Retina ◽  
Light Pulses ◽  
Opal Glass ◽  
Modulator Tube ◽  
Design Integration ◽  
Glass Target

The temporal integration of luminous energy was compared in the fovea and at 7° eccentricity using two-pulse stimuli and two methodologies The two-pulse stimuli consisted of two 1-msec. light pulses separated by intervals of darkness ranging from 1 to 400 msec; they were provided by a glow modulator tube transilluminating a 21.8' opal glass target. In Exp. 1 (equal-performance design), integration functions were generated using a forced-choice staircase procedure to estimate threshold luminance. The data for two Os showed that the critical duration (CD), and thus the period of complete integration, was briefer in the fovea than at 7°. Beyond the CD, integration continued to differ for the two retinal locations. In the fovea, two-pulse stimuli beyond CD evidenced partial integration and at the longest stimulus durations no integration or inhibition. In contrast, at 7° stimuli beyond CD appeared to evidence probability summation. In Exp. 2 (equal-energy design), integration functions were generated by measuring the detectability of two-pulse stimuli of different durations but equal in total luminous energy. A signal-detection procedure yielded measures of both response frequency and signal detectability, P(A). The data for two Os showed that for both measures CD was briefer in the fovea than at 7°. Also, in the fovea, long two-pulse stimuli appeared to show no integration or inhibition. Both experiments then showed a foveal-peripheral difference in two-pulse measures of visual temporal integration, with the fovea evidencing less integration. In addition, the forced-choice and signal-detection procedures showed that these loci differences in integration were independent of the Os' response criterion.

Signal Detection Analysis of Visual Flicker in Deaf and Hearing Individuals

1980 ◽  
Vol 51 (3) ◽  
pp. 839-843 ◽  
Author(s):  
Michael Bross ◽  
Hannelore Sauerwein
Keyword(s):  
Signal Detection ◽  
Response Bias ◽  
Forced Choice ◽  
Resolving Power ◽  
Stimulus Probability ◽  
Sensory Sensitivity ◽  
Detection Analysis ◽  
Signal Detection Analysis ◽  
Flicker Task ◽  
Sensory Compensation

A comparison of deaf and hearing subjects on temporal visual resolving power was conducted within a signal-detection paradigm. Subjects were required to make forced-choice judgments of a visual-flicker task under three stimulus probability conditions (0.25, 0.50, and 0.75). A total of 600 trials were given each subject from which d′ and Beta, indices for sensory sensitivity and response bias respectively, were computed. No significant differences existed on sensory sensitivity or response bias which questions some traditional assumptions about sensory compensation.

Effects of Payoff on Detection in a Symmetric Auditory Detection Task

1970 ◽  
Vol 31 (3) ◽  
pp. 895-901
Author(s):  
Robert C. Calfee
Keyword(s):  
Signal Detection ◽  
Detection Rate ◽  
Periodic Variation ◽  
Forced Choice ◽  
Detection Task ◽  
Auditory Signal ◽  
Auditory Detection ◽  
Signal Detection Task ◽  
Error Probabilities

The assumption common to several models for signal detection, that increased payoff should have no effect on detection rate, was tested in a two-interval forced-choice auditory signal detection task. The signal occurred equally often in each interval, and amount of gain or loss was the same for both intervals. Payoff values (0, .1, .5, and 1 cent) were changed within sessions in 50-trial blocks. Detection rate increased noticeably in one experiment, was significant in a second experiment and had no effect in a third. With minimal payoffs of the sort typically used, significant effects may depend on convincing S of the importance of the incentive. Analysis of conditional error probabilities showed that errors were more likely to follow errors, which suggests periodic variation in level of attention.

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