Visual detection of signals in the presence of continuous and pulsed backqrounds

Leshowitz, Barry; Tavb, Harvey B.; Raab, David H.

doi:10.3758/bf03206303

Cited by 125 publications

(58 citation statements)

References 21 publications

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“…10 This is related to the observation that dЈ increases as a nonlinear function of signal contrast (Cohn et al, 1974;Foley & Legge, 1981;Leshowitz et al, 1968;Nachmias, 1981;Nachmias & Kocher, 1970;Nachmias & Sansbury, 1974;Stromeyer & Klein, 1974;Tanner, 1961). The important finding here is that the threshold ratios are invariant in many experiments.…”

Section: Existing Evidencementioning

confidence: 76%

“…It has been well established that perceptual sensitivity (dЈ) increases as a nonlinear function of signal contrast (Cohn, Thibos, & Kleinstein, 1974;Foley & Legge, 1981;Leshowitz, Taub, & Raab, 1968;Nachmias, 1981;Nachmias & Kocher, 1970;Nachmias & Sansbury, 1974;Stromeyer & Klein, 1974;Tanner, 1961). Some researchers (e.g., Foley & Legge, 1981;Nachmias & Sansbury, 1974) have attributed the nonlinear relation between dЈ and signal contrast to some form of nonlinear transformation, or transducer function, acting on the stimulus strength; others have attributed the nonlinearity to statistical uncertainty in the decision process (Eckstein et al, 1997;Pelli, 1985).…”

Section: Triple Tvcmentioning

confidence: 99%

“…However, it has been well established in the visual domain that the observed dЈ obs increases as a power function of signal contrast (Cohn et al, 1974;Foley & Legge, 1981;Leshowitz et al, 1968;Nachmias, 1981;Nachmias & Kocher, 1970;Nachmias & Sansbury, 1974;Stromeyer & Klein, 1974;Tanner, 1961). Pelli (1985) proposed that the nonlinear relationship is due to statistical uncertainty in the decision process, that is, the observer is uncertain about some aspects of the signal and therefore makes decisions based not only on task-relevant decision variables but also on task-irrelevant decision variables.…”

Section: Linear Amplifier Model With Uncertaintymentioning

confidence: 99%

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Characterizing observers using external noise and observer models: Assessing internal representations with external noise.

Lü¹,

Dosher²

2008

Psychological Review

228

347

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External noise methods and observer models have been widely used to characterize the intrinsic perceptual limitations of human observers and changes of the perceptual limitations associated with cognitive, developmental, and disease processes by highlighting the variance of internal representations. The authors conducted a comprehensive review of the 5 most prominent observer models through the development of a common formalism. They derived new predictions of the models for a common set of behavioral tests that were compared with the data in the literature and a new experiment. The comparison between the model predictions and the empirical data resulted in very strong constraints on the observer models. The perceptual template model provided the best account of all the empirical data in the visual domain. The choice of the observer model has significant implications for the interpretation of data from other external noise paradigms, as well as studies using external noise to assay changes of perceptual limitations associated with observer states. The empirical and theoretical development suggests possible parallel developments in other sensory modalities and studies of high-level cognitive processes.Keywords: signal detection theory, internal representation, observer model, perceptual template, internal noise Human decisions are based on internal representations of information. Understanding how stimuli are represented internally is one of the classic problems in psychology. This article examines how modifying an external stimulus with external noise can provide insight into how the stimulus is processed by the human observer. We conducted a systematic and comprehensive review of the external noise paradigms and observer models widely used in characterizing the internal response properties of human observers. The observer approach builds on the broadly applicable framework of signal detection theory (SDT) by elaborating the relationships between external stimuli and the internal response distributions that form the basis for decision. The empirical tests introduce external noise-either masking noise or variation in the relevant stimulus dimension-to provide a reference for characterizing and quantifying the limiting factors in perceptual sensitivity. The current review, analysis, and empirical test focus on visual perception. Some of the model properties, especially the empirical findings, may be modality specific. Still, this framework and the findings could serve as an example for parallel development of the empirical methods and theoretical models in other sensory modalities. The model development and testing also have major implications for applications of the external noise paradigms in understanding the mechanisms underlying changes of perceptual sensitivity in different cognitive, disease, and/or developmental states. Internal Response DistributionsSDT provides a general framework for analyzing human decision making in perceptual and cognitive tasks (Green & Swets, 1966;Macmillan & Creelman, 1991). In a ...

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Section: Existing Evidencementioning

confidence: 76%

Section: Triple Tvcmentioning

confidence: 99%

Section: Linear Amplifier Model With Uncertaintymentioning

confidence: 99%

See 1 more Smart Citation

Characterizing observers using external noise and observer models: Assessing internal representations with external noise.

Lü¹,

Dosher²

2008

Psychological Review

228

347

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“…This transducer function has an acceleration (second derivative) which is approximately constant for > 2 and which falls quadratically to zero as approaches zero. Transducer functions of the accelerated form dwith an exponent p = 2-3, have been found for the detection of spots of light on a background (Nachmias and Kocher, 1970;Leshowitz, Taub and Raab, 1968) and for gratings (Nachmias and Sansbury, 1974;Klein et al, in preparation). The transducer used for the present study has p = 4 for low and p = 2 for large In order to predict the detectability of the test grating, denoted d T , in the presence of the background grating, an expression is needed that relates d T to d' B , the detectability of the background grating, and d' T + B , the detectability of the test plus background grating.…”

Section: Discussionmentioning

confidence: 99%

Spatial frequency channels in human vision as asymmetric (edge) mechanisms

1974

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“…In practice Weber's law holds over a large part of the luminance domain (e.g. Leshowitz et al 1968). Weber's law is of course not restricted to discriminations of luminance and holds approximately over the greater part of the operating range of many sensory attributes (Laming 1986), and it has been used as a criterion for the acceptability of models of discrimination performance (Falmagne 1985).…”

Section: Weber's Law and Viewpoint Invariancementioning

confidence: 99%

Viewpoint-invariant Weber fractions and standard contour-curvature discrimination

Foster

Wagemans

1993

Biol. Cybern.

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Abstract. It is proposed that any cue for the visual discrimination of shape, in particular the discrimination of curved contours, should be such that the perceptual relationships defined by the cue are invariant under changes in observer viewpoint. Such relationships may be quantified by the Weber fraction; that is, the ratio Ac/c, where, for any particular value c of the cue, Ac is the smallest difference in c that can be detected. Eight geometric attributes of curved contours having one symmetry axis and parallel chords (a standard stimulus configuration) were examined for invariance of the Weber fraction under symmetry-preserving affine transformations of the image plane (changes in viewpoint are well approximated by affine transformations when depth is small relative to viewing distance). The attributes, each investigated in previous psychophysical studies, were equivalent-curvature, radius-of-curvature, turning-angle, arc-length-divided-by-chord-length, arc-length, maximumdeviation (sag), area, and mean-deviation. Three of the attributes, namely sag, area, and mean-deviation, satisfied the viewpoint-invariance condition; the remainder failed. These results are considered in relation to previously published empirical data on the Weber fraction for contour-curvature discrimination.

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Visual detection of signals in the presence of continuous and pulsed backqrounds

Cited by 125 publications

References 21 publications

Characterizing observers using external noise and observer models: Assessing internal representations with external noise.

Characterizing observers using external noise and observer models: Assessing internal representations with external noise.

Spatial frequency channels in human vision as asymmetric (edge) mechanisms

Viewpoint-invariant Weber fractions and standard contour-curvature discrimination

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