Intensity Discrimination in the Human Eye

Hecht, Selig; Peskin, James C.; Patt, Marjorie

doi:10.1085/jgp.22.1.7

Cited by 57 publications

(10 citation statements)

References 9 publications

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“…Why do the curves for the different wavelengths line up as they do in our experiment and in the classical data of intensity discrimination (Hecht, Peskin, & Patt, 1938) and CFF (Hecht & Shlaer, 1936)? In all these figures, the data break into two sections.…”

Section: Discussionmentioning

confidence: 61%

Reaction time to different wavelengths at various luminances

Pollack

1968

Perception & Psychophysics

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The present investigation is concerned with determining whether or not differences in the reaction times er ist in a human subject's responses to 6 different wavelengths equated at 5 The problem as to whether or not there are differences in the reaction times to different wavelengths at constant luminance is a question of considerable theoretical and practical significance. The question relates to a large literature in color theory concerning the various visual functions obtained not only with latency measurements but also with critical flicker frequency, intensity discrimination, and visual acuity experiments as well.In 1906, Henmon, a student of Cattell, measured the time to perceive differences between pairs of colors by the method of disjunctive reaction. Colored cards were used as stimuli and no attempt was made to equate them for luminance. Henmon found that discrimination time was about the same for red and green as for blue and yellow. However, the reaction times for the red-blue and greenyellow combinations were longer for both subjects. In discussing his results, Henmon attrtputed the differences in perception time for the red and blue to a difference in brightness between the colored stimulus cards while the longer discrimination time for the green and yellow stimuli was ascribed to the proximity of the two colors in the spectrum.In spite of the discrepancies in his data, Henmon maintained that different wavelengths which have been equated for brightness would show no difference in average reaction time.Another attempt to measure the reaction times to lights of variOUS wavelengths was made by Holmes in 1923. Holmes equated the luminances of the colored lights at one level of luminance with a standard flicker photometer and his results, obtained with two subjects, justified his conclusion that simple reaction time is not influenced by the wavelength of the stimulus.In the same year as Holmes ' experiment, Pieron (1923), in order to explain the colorations of the rings produced by rotation of Benham's top, proposed that there was a difference among the timeconstants for sensation of the three fundamental colors of the trichromatic system (Broca-Sulzer effect). The perception of the blue system was the slowest to appear and to reach its transitory maximum, the slowest also to disappear; the red was quickest of the three, and green was interposed between red and blue.In his theory, Pieron (1952) proposed the independence of the system mediating chromatic and the system mediating brightness sensation. In 1932, Pieron used simple reaction time to study the onset of a chromatic sensation (Le., reaction time to the perception of color) and found an average minimum latency for red light and an average maximum latency for blue light with a difference of about 30 msec between them. The average reaction time to color for green light was found to be intermediate between the red and the blue. The influence of light of different wavelengths on the latency of the sensation of brightness was determined by Liang and...

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Section: Discussionmentioning

confidence: 61%

Reaction time to different wavelengths at various luminances

Pollack

1968

Perception & Psychophysics

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“…Essentially all of the classical visual functions, such as visual acuity (Shlaer, 1937), flicker, (Hecht & Verrijp, 1933), stereoscopic depth (Mueller & Lloyd, 1948), and brightness discrimination (Hecht, Peskin, & Patt, 1938), as well as reaction time (Teichner & Krebs, 1972), are very sensitive to luminance, demonstrating a marked improvement in performance with increasing luminance before reach- ing an asymptote at higher luminance levels. Correspondingly, a large proportion of the psychophysical literature is concerned with the effect of manipulation of luminous energy in the form of luminance level and/or duration of exposure.…”

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confidence: 99%

The independence of dynamic spatial orientation from luminance and refractive error

Leibowitz

Rodemer

Dichgans

1979

Perception & Psychophysics

103

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The effect of refractive error and luminance on circularvection, the illusory sensation of self-motion resulting from rotation of the visual field, was determined. Neither reduction of luminance to levels near absolute scotopic threshold nor induced refractive errors of more than 16 diopters abolished circularvection or influenced any of its latency measures. The results are discussed in terms of the role of the peripheral visual field and the nature of the visual stimulus in ego orientation.A growing body of literature suggests that the central retinal regions are concerned primarily with form perception and object recognition, while the periphery is specialized for visual localization of objects and orientation in space (

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“…Moreover, it can be assumed that discriminability (Weber ratios) varies with the luminance levels, but not exactly in the same way for the scotopic and photopic ranges (see, e.g., Graham, 1965;Hecht, 1934;Hecht, Peskin, & Patt, 1938;Hood & Finkelstein, 1986). A similar conclusion holds for luminance adaptation (Haig, 1941;Hecht & Shlaer, 1938;Hood & Finkelstein, 1986).…”

Section: Nomamentioning

confidence: 99%

Reaction times reveal the contribution of the different receptor components in luminance perception

Pins¹,

Brunet²

1997

Psychonomic Bulletin & Review

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Pieron (1914, 1920,1952)demonstrated that simple reaction time decays as a hyperbolic function of luminance. Similarities between cell latencies and reaction time (RT) to luminance suggest that this relationship may be determined by retinal processes. Ifthe exponent of the Pieron function is specific to a given sensory modality, as assumed by some authors (e.g., Bonnet, 1992aBonnet, , 1992bNorwich, 1987), it should reflect receptor activities. Consequently, functions with different exponents should fit data for different luminance ranges. In a contrast-discrimination experiment, we investigated this question with a large range of luminance levels in a two-alternative spatial forced-choice task. The results of the experiment show that three functions with different exponents fit RTto the three luminance ranges (scotopic, mesopic, and photopic). The exponent decreases with increasing luminance. The findings indicate that the exponent and the asymptotic latency of the RT function reflect receptor activities of the visual system. Classically, data obtained in experiments relating reaction time (RT) to intensity are fitted to a single power function. Simple reaction time (SRT) decreases when the intensity of a given stimulus increases (see, e.g., Cattell, 1886;Exner, 1868;Pieron, 1914Pieron, , 1920Pieron, , 1952Wundt, 1886). The original equation for this function was introduced by Pieron (1914Pieron ( ,1920Pieron ( ,1952:where SRT is simple reaction time, to is the asymptotic RT reached at the highest stimulus intensities, f3 is a free parameter, I is the intensity of the stimulus, and a is the exponent of the function.Some authors have provided evidence that choice reaction time (CRT) also decreases when the luminance of the stimulus increases (e.g., Lappin & Dish, 1972;Pachella & Fisher, 1969;Posner, 1986). Moreover, Pins and Bonnet (1996) have shown that the Pieron function adequately describes the relationship between CRT and luminance and that the exponent of the function does not change with the complexity of the psychophysical task. In particular, it does not seem to matter whether the task is an SRT or a CRT task. Pieron functions would differ only by the constant to and the parameter f3.Thanks are due to J. C. Baird, L. M. Ward, and J. E. Cutting for their insightful comments and suggestions on an earlier version ofthis paper. Correspondence should be addressed to D. Pins, Laboratoire de Psychophysique Sensorielle (EP618, C.N.R.S.), Universite Louis Pasteur, 12 rue Goethe, F-67000, Strasbourg, France (e-mail: dpins@currifl.u-strasbg.fr).Similarities between measures ofcell latency and measures of RT to luminance have been reported. On the basis of a comparison of RT, alpha blocking latency, and the latency ofb-wave ofthe electroretinogram, Bernhard (1940) concluded that all three measures followed a similar function, differing only by an additive constant. Monnier (1949) reached the same conclusion by studying retinal time, retinocortical time, alpha blocking time, and motor RT. Later, using computer-averag...

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Intensity Discrimination in the Human Eye

Cited by 57 publications

References 9 publications

Reaction time to different wavelengths at various luminances

Reaction time to different wavelengths at various luminances

The independence of dynamic spatial orientation from luminance and refractive error

Reaction times reveal the contribution of the different receptor components in luminance perception

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