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Abstract
Psychophysical scaling models of the form R = f(I), with R the response and I some intensity of an attribute, all assume that people judge the amounts of an attribute. With simple biases excepted, most also assume that judgments are independent of space, time, and features of the situation other than the one being judged. Many data support these ideas: Magnitude estimations of brightness (R) increase with luminance (I). Nevertheless, I argue that the general model is wrong. The stabilized retinal image literature shows that nothing is seen if light does not change over time. The classification literature shows that dimensions often combine to produce emergent properties that cannot be described by the elements in the stimulus. These and other effects cannot be adjusted for by simply adding variables to the general model because some factors do not combine linearly. The proposed alternative is that people initially judge the entire stimulus - the object in terms of its environment. This agrees with the constancy literature that shows that objects and their attributes are identified through their relations to other aspects of the scene. That the environment determines judgments is masked in scaling studies where the standard procedure is to hold context constant. In a typical brightness study (where different lights are presented on the same background on different trials) the essential stimulus might be the intensity of the light or a difference between the light and the background. The two are perfectly confounded. This issue is examined in the case of audition. Judgments of the loudness of a tone depend on how much that tone differs from the previous tone in both pitch and loudness. To judge loudness (and other attributes) people first seem to process the stimulus object in terms of differences between it and other aspects in the situation; only then do they assess the feature of interest. Psychophysical judgments will therefore be better interpreted by theories of attention that are based in biology or psychology than those (following Fechner) that are based in classical physics.
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Accounting for an old inconsistency in the psychophysics of Plateau and Delboeuf. Behav Brain Sci 2011; 15:562-3. [DOI: 10.1017/s0140525x00069995] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Abstract
The brightness of an achromatic surface with luminance S on an achromatic background with luminance B varies with S, with B, and with the luminance step deltaL at the border of the surface. In agreement with previous findings indicating that the visual system can perform as a photometer, the results of the two experiments reported here show that S and B determined surface brightness independently of deltaL when the surface was adjacent to and when it was separated from the background. This finding suggests that surface brightness depends on the integration of neural signals representing magnitudes of absolute luminance. A weighted-average model of this integration is proposed.
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Schouten G, Blommaert FJ. Brightness constancy in a Ganzfeld environment. PERCEPTION & PSYCHOPHYSICS 1995; 57:1012-22. [PMID: 8532491 DOI: 10.3758/bf03205460] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
In this paper, experiments are described in which brightness constancy was studied in a Ganzfeld environment. Luminance variation by means of neutral density filters was applied to stimuli consisting of a Ganzfeld with superimposed disks. To this end, a special-purpose apparatus was constructed. Sequential dichoptical brightness matches with a reference stimulus were carried out for the disks as well as the homogeneous surround. The results of these measurements indicate that (1) besides a clear tendency toward brightness constancy, small but systematic effects of the average luminance level are present and (2) the brightness of the Ganzfeld is hardly affected by the presence of the disks. Finally, it is shown that the experimental results can be modeled adequately in terms of a concept that involves an accumulation of contrast information.
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Affiliation(s)
- G Schouten
- Institute for Perception Research (IPO), Eindhoven, The Netherlands
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How important are dimensions to perception? Behav Brain Sci 1992; 15:576-7. [DOI: 10.1017/s0140525x0007014x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Psychophysics: Plus ça change …. Behav Brain Sci 1992; 15:569. [DOI: 10.1017/s0140525x00070072] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Context effects: Pervasiveness and analysis. Behav Brain Sci 1992; 15:570. [DOI: 10.1017/s0140525x00070084] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Keeping the bath water along with the baby: Context effects represent a challenge, not a mortal wound, to the body of psychophysics. Behav Brain Sci 1992; 15:585-6. [DOI: 10.1017/s0140525x00070229] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Scales falling from the eyes? Behav Brain Sci 1992; 15:567-8. [DOI: 10.1017/s0140525x00070059] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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The determinants of perceived brightness are complicated, but not hopelessly so. Behav Brain Sci 1992; 15:564-5. [PMID: 24924053 DOI: 10.1017/s0140525x00070011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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The complexity and importance of the psychophysical scaling of sensory attributes. Behav Brain Sci 1992; 15:567. [PMID: 24924056 DOI: 10.1017/s0140525x00070047] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Should the psychophysical model be rejected? Behav Brain Sci 1992; 15:579-80. [PMID: 24924070 DOI: 10.1017/s0140525x00070187] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Constancy in a changing world. Behav Brain Sci 1992. [DOI: 10.1017/s0140525x00070242] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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Walking in a psychophysical dustbowl creates a dustcloud. Behav Brain Sci 1992; 15:568-9. [DOI: 10.1017/s0140525x00070060] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Covert converging operations for multidimensional psychophysics. Behav Brain Sci 1992; 15:573-4. [DOI: 10.1017/s0140525x00070114] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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The perplexing plurality of psychophysical processes. Behav Brain Sci 1992; 15:574-5. [DOI: 10.1017/s0140525x00070126] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Bolanowski SJ, Doty RW. Perceptual "blankout" of monocular homogeneous fields (Ganzfelder) is prevented with binocular viewing. Vision Res 1987; 27:967-82. [PMID: 3660657 DOI: 10.1016/0042-6989(87)90012-5] [Citation(s) in RCA: 68] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
The loss of visual perception or "blankout" which occurs when a homogeneous field (Ganzfeld) is presented monocularly is prevented when the same field is viewed binocularly. Thus, blankout cannot be retinal; and contours or transients in time and space are unnecessary for the continuous maintenance of visual perception. Experiments are reported in which blankout ensues only if the two eyes receive luminance disparities ca 0.75 log I. Furthermore, blankout is only marginally affected by stimulus intensity, nor is it dependent on stimulus hue. However, equally luminant but disparate hues presented to the two eyes produce perceptions reminiscent of blankout, with the darkness of blankout replaced with that of color. It is hypothesized that the underlying mechanisms have a commonality in the phenomena of blankout and binocular rivalry but several noncongruent features require explanation.
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Affiliation(s)
- S J Bolanowski
- Center for Brain Research, University of Rochester Medical School, NY 14642
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Krumhansl CL. Abrupt changes in visual stimulation enhance processing of form and location information. PERCEPTION & PSYCHOPHYSICS 1982; 32:511-23. [PMID: 7167348 DOI: 10.3758/bf03204204] [Citation(s) in RCA: 35] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
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Osaka N. Exponent of the Broca-Sulzer flash duration as a function of retinal eccentricity. JOURNAL OF THE OPTICAL SOCIETY OF AMERICA 1982; 72:62-7. [PMID: 7057287 DOI: 10.1364/josa.72.000062] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
The flash duration producing maximum brightness-enhancement changes as a power function of luminance, that is, the time locus of the Broca-Sulzer flash duration TB, decreases as luminance L increases: TB = k x L beta , where beta is the duration exponent. The exponent of TB was estimated for 1-deg white flash fovea, 10-, 20-, 30-, 40-, 50-, and 60-deg temporal eccentricities of the dark-adapted human right eye. The following method of brightness maximization was used: the observer adjusted the duration of constant luminance flashes to produce a maximally bright flash. Duration was adjusted by rotating a microprocessor-based potentiometer. The results showed that the duration of the brightest flash TB decreased as L increased with the negative power exponent. Furthermore, the size of the negative exponent decreased as a function of increasing retinal eccentricity. Time-dependent brightness processing in the fovea and periphery is discussed in terms of the psychophysical brightness power function.
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