Abstract

The question of whether first-order (luminance-defined) and second-order (contrast-defined) stimuli can be combined in order to improve perceptual accuracy was examined in the context of two suprathreshold discrimination experiments, one spatial and the other temporal. The stimuli were either gratings of one type of image alone or else the sum of two gratings of the same orientation, spatial frequency, temporal frequency, and phase, but of different types. For both spatial frequency discrimination (static gratings) and speed discrimination (1-c/deg drifting gratings), performance was markedly better for a combined grating stimulus than predicted on the basis of independent processing of the two types of stimulus. But this was true only for stimuli of low contrast. Facilitation of discrimination performance occurred only in the contrast range where discrimination performance is contrast dependent. At higher contrasts, where performance has reached an asymptote for each type of pattern alone, there was no facilitation. The results suggest that first- and second-order stimuli, although believed by most researchers to be detected separately, can subsequently be combined in order to improve perceptual accuracy in conditions of low visibility.

© 2001 Optical Society of America

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References

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    [CrossRef]
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    [CrossRef] [PubMed]
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    [CrossRef] [PubMed]
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    [CrossRef] [PubMed]
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    [CrossRef] [PubMed]
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    [CrossRef] [PubMed]
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    [CrossRef] [PubMed]
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    [CrossRef]
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2000

N. Scott-Samuel, A. Smith, “No local cancellation between directionally opposed first-order and second-order motion signals,” Vision Res. 40, 3495–3500 (2000).
[CrossRef] [PubMed]

1999

N. Scott-Samuel, A. Smith, “Greater than the sum of its parts: first- and second-order stimuli combine to improve perceptual accuracy for both motion and form,” Invest. Ophthalmol. Visual Sci. Suppl. 40, S425 (1999).

N. E. Scott-Samuel, M. A. Georgeson, “Does early non-linearity account for second-order motion?” Vision Res. 39, 2853–2865 (1999).
[CrossRef] [PubMed]

A. J. Schofield, M. A. Georgeson, “Sensitivity to modulations of luminance and contrast in visual white noise: separate mechanisms with similar behaviour,” Vision Res. 39, 2697–2716 (1999).
[CrossRef] [PubMed]

1998

R. Gray, D. Regan, “Spatial frequency discrimination and detection characteristics for gratings defined by orientation texture,” Vision Res. 38, 2601–2617 (1998).
[CrossRef]

1997

A. T. Smith, T. Ledgeway, “Separate detection of moving luminance and contrast modulations: fact or artifact?” Vision Res. 37, 45–62 (1997).
[CrossRef] [PubMed]

S. Nishida, T. Ledgeway, M. Edwards, “Dual multiple-scale processing for motion in the human visual system,” Vision Res. 37, 2685–2698 (1997).
[CrossRef] [PubMed]

T. Ledgeway, A. T. Smith, “Changes in perceived speed following adaptation to first-order and second-order motion,” Vision Res. 37, 215–224 (1997).
[CrossRef] [PubMed]

A. Johnston, C. P. Benton, “Speed discrimination thresholds for first- and second-order bars and edges,” Vision Res. 37, 2217–2226 (1997).
[CrossRef] [PubMed]

1996

L.-M. Lin, H. R. Wilson, “Fourier and non-Fourier pattern discrimination compared,” Vision Res. 36, 1907–1918 (1996).
[CrossRef] [PubMed]

1994

T. Ledgeway, A. T. Smith, “Evidence for separate motion-detecting mechanisms for first- and second-order motion in human vision,” Vision Res. 34, 2727–2740 (1994).
[CrossRef] [PubMed]

S. J. Cropper, “Velocity discrimination in chromatic gratings and beats,” Vision Res. 34, 41–48 (1994).
[CrossRef] [PubMed]

T. Ledgeway, “Adaptation to second-order motion results in a motion aftereffect for directionally-ambiguous test stimuli,” Vision Res. 34, 2879–2889 (1994).
[CrossRef] [PubMed]

1993

G. Mather, S. West, “Evidence for second-order motion detectors,” Vision Res. 33, 1109–1112 (1993).
[CrossRef] [PubMed]

1992

H. R. Wilson, V. P. Ferrera, C. Yo, “A psychophysically motivated model for two-dimensional motion perception,” Visual Neurosci. 9, 79–97 (1992).
[CrossRef]

1990

S. F. Bowne, “Contrast discrimination cannot explain spatial frequency, orientation or temporal frequency resolution,” Vision Res. 30, 449–461 (1990).
[CrossRef]

1989

K. Turano, A. Pantle, “On the mechanism that encodes the movement of contrast variations: velocity discrimination,” Vision Res. 29, 207–221 (1989).
[CrossRef] [PubMed]

C. Chubb, G. Sperling, “Two motion perception mechanisms revealed through distance-driven reversal of apparent motion,” Proc. Natl. Acad. Sci. USA 86, 2985–2989 (1989).
[CrossRef] [PubMed]

1988

1986

S. P. McKee, G. Silverman, K. Nakayama, “Precise velocity discrimination despite random variations in temporal frequency and contrast,” Vision Res. 26, 609–619 (1986).
[CrossRef] [PubMed]

1985

A. M. Derrington, D. R. Badcock, “Separate detectors for simple and complex patterns?” Vision Res. 25, 1869–1878 (1985).
[CrossRef]

H. Northdurft, “Orientation sensitivity and texture segmentation in patterns with different line orientation,” Vision Res. 25, 551–560 (1985).
[CrossRef]

1984

G. Orban, J. D. Wolf, H. Maes, “Factors influencing velocity coding in the human visual system,” Vision Res. 24, 33–39 (1984).
[CrossRef] [PubMed]

1983

1982

D. Regan, S. Bartol, T. Murray, K. Beverley, “Spatial frequency discrimination in normal vision and in patients with multiple sclerosis,” Brain 105, 735–754 (1982).
[CrossRef] [PubMed]

1981

B. Julesz, “Textons, the elements of texture perception, and their interactions,” Nature 290, 91–97 (1981).
[CrossRef] [PubMed]

1980

1968

F. W. Campbell, J. G. Robson, “Application of Fourier analysis to the visibility of gratings,” J. Physiol. 197, 551–566 (1968).
[PubMed]

Badcock, D. R.

A. M. Derrington, D. R. Badcock, “Separate detectors for simple and complex patterns?” Vision Res. 25, 1869–1878 (1985).
[CrossRef]

Bartol, S.

D. Regan, S. Bartol, T. Murray, K. Beverley, “Spatial frequency discrimination in normal vision and in patients with multiple sclerosis,” Brain 105, 735–754 (1982).
[CrossRef] [PubMed]

Benton, C. P.

A. Johnston, C. P. Benton, “Speed discrimination thresholds for first- and second-order bars and edges,” Vision Res. 37, 2217–2226 (1997).
[CrossRef] [PubMed]

Beverley, K.

D. Regan, S. Bartol, T. Murray, K. Beverley, “Spatial frequency discrimination in normal vision and in patients with multiple sclerosis,” Brain 105, 735–754 (1982).
[CrossRef] [PubMed]

Bowne, S. F.

S. F. Bowne, “Contrast discrimination cannot explain spatial frequency, orientation or temporal frequency resolution,” Vision Res. 30, 449–461 (1990).
[CrossRef]

Campbell, F. W.

F. W. Campbell, J. G. Robson, “Application of Fourier analysis to the visibility of gratings,” J. Physiol. 197, 551–566 (1968).
[PubMed]

Chubb, C.

C. Chubb, G. Sperling, “Two motion perception mechanisms revealed through distance-driven reversal of apparent motion,” Proc. Natl. Acad. Sci. USA 86, 2985–2989 (1989).
[CrossRef] [PubMed]

C. Chubb, G. Sperling, “Drift-balanced random stimuli: a general basis for studying non-Fourier motion perception,” J. Opt. Soc. Am. A 5, 1986–2006 (1988).
[CrossRef] [PubMed]

Cropper, S. J.

S. J. Cropper, “Velocity discrimination in chromatic gratings and beats,” Vision Res. 34, 41–48 (1994).
[CrossRef] [PubMed]

Derrington, A. M.

A. M. Derrington, D. R. Badcock, “Separate detectors for simple and complex patterns?” Vision Res. 25, 1869–1878 (1985).
[CrossRef]

Edwards, M.

S. Nishida, T. Ledgeway, M. Edwards, “Dual multiple-scale processing for motion in the human visual system,” Vision Res. 37, 2685–2698 (1997).
[CrossRef] [PubMed]

Ferrera, V. P.

H. R. Wilson, V. P. Ferrera, C. Yo, “A psychophysically motivated model for two-dimensional motion perception,” Visual Neurosci. 9, 79–97 (1992).
[CrossRef]

Foley, J. M.

Georgeson, M. A.

N. E. Scott-Samuel, M. A. Georgeson, “Does early non-linearity account for second-order motion?” Vision Res. 39, 2853–2865 (1999).
[CrossRef] [PubMed]

A. J. Schofield, M. A. Georgeson, “Sensitivity to modulations of luminance and contrast in visual white noise: separate mechanisms with similar behaviour,” Vision Res. 39, 2697–2716 (1999).
[CrossRef] [PubMed]

Gray, R.

R. Gray, D. Regan, “Spatial frequency discrimination and detection characteristics for gratings defined by orientation texture,” Vision Res. 38, 2601–2617 (1998).
[CrossRef]

Johnston, A.

A. Johnston, C. P. Benton, “Speed discrimination thresholds for first- and second-order bars and edges,” Vision Res. 37, 2217–2226 (1997).
[CrossRef] [PubMed]

Julesz, B.

B. Julesz, “Textons, the elements of texture perception, and their interactions,” Nature 290, 91–97 (1981).
[CrossRef] [PubMed]

Ledgeway, T.

S. Nishida, T. Ledgeway, M. Edwards, “Dual multiple-scale processing for motion in the human visual system,” Vision Res. 37, 2685–2698 (1997).
[CrossRef] [PubMed]

A. T. Smith, T. Ledgeway, “Separate detection of moving luminance and contrast modulations: fact or artifact?” Vision Res. 37, 45–62 (1997).
[CrossRef] [PubMed]

T. Ledgeway, A. T. Smith, “Changes in perceived speed following adaptation to first-order and second-order motion,” Vision Res. 37, 215–224 (1997).
[CrossRef] [PubMed]

T. Ledgeway, “Adaptation to second-order motion results in a motion aftereffect for directionally-ambiguous test stimuli,” Vision Res. 34, 2879–2889 (1994).
[CrossRef] [PubMed]

T. Ledgeway, A. T. Smith, “Evidence for separate motion-detecting mechanisms for first- and second-order motion in human vision,” Vision Res. 34, 2727–2740 (1994).
[CrossRef] [PubMed]

Legge, G. E.

Lin, L.-M.

L.-M. Lin, H. R. Wilson, “Fourier and non-Fourier pattern discrimination compared,” Vision Res. 36, 1907–1918 (1996).
[CrossRef] [PubMed]

Maes, H.

G. Orban, J. D. Wolf, H. Maes, “Factors influencing velocity coding in the human visual system,” Vision Res. 24, 33–39 (1984).
[CrossRef] [PubMed]

Mather, G.

G. Mather, S. West, “Evidence for second-order motion detectors,” Vision Res. 33, 1109–1112 (1993).
[CrossRef] [PubMed]

McKee, S. P.

S. P. McKee, G. Silverman, K. Nakayama, “Precise velocity discrimination despite random variations in temporal frequency and contrast,” Vision Res. 26, 609–619 (1986).
[CrossRef] [PubMed]

Murray, T.

D. Regan, S. Bartol, T. Murray, K. Beverley, “Spatial frequency discrimination in normal vision and in patients with multiple sclerosis,” Brain 105, 735–754 (1982).
[CrossRef] [PubMed]

Nakayama, K.

S. P. McKee, G. Silverman, K. Nakayama, “Precise velocity discrimination despite random variations in temporal frequency and contrast,” Vision Res. 26, 609–619 (1986).
[CrossRef] [PubMed]

Nishida, S.

S. Nishida, T. Ledgeway, M. Edwards, “Dual multiple-scale processing for motion in the human visual system,” Vision Res. 37, 2685–2698 (1997).
[CrossRef] [PubMed]

Northdurft, H.

H. Northdurft, “Orientation sensitivity and texture segmentation in patterns with different line orientation,” Vision Res. 25, 551–560 (1985).
[CrossRef]

Orban, G.

G. Orban, J. D. Wolf, H. Maes, “Factors influencing velocity coding in the human visual system,” Vision Res. 24, 33–39 (1984).
[CrossRef] [PubMed]

Panish, S. C.

S. C. Panish, “Velocity discrimination at constant multiples of threshold contrast,” Vision Res. 28, 193–201 (1988).
[CrossRef] [PubMed]

Pantle, A.

K. Turano, A. Pantle, “On the mechanism that encodes the movement of contrast variations: velocity discrimination,” Vision Res. 29, 207–221 (1989).
[CrossRef] [PubMed]

Regan, D.

R. Gray, D. Regan, “Spatial frequency discrimination and detection characteristics for gratings defined by orientation texture,” Vision Res. 38, 2601–2617 (1998).
[CrossRef]

D. Regan, S. Bartol, T. Murray, K. Beverley, “Spatial frequency discrimination in normal vision and in patients with multiple sclerosis,” Brain 105, 735–754 (1982).
[CrossRef] [PubMed]

D. Regan, Human Perception of Objects (Sinauer, Sunderland, Mass., 2000).

Robson, J. G.

F. W. Campbell, J. G. Robson, “Application of Fourier analysis to the visibility of gratings,” J. Physiol. 197, 551–566 (1968).
[PubMed]

Schofield, A. J.

A. J. Schofield, M. A. Georgeson, “Sensitivity to modulations of luminance and contrast in visual white noise: separate mechanisms with similar behaviour,” Vision Res. 39, 2697–2716 (1999).
[CrossRef] [PubMed]

Scott-Samuel, N.

N. Scott-Samuel, A. Smith, “No local cancellation between directionally opposed first-order and second-order motion signals,” Vision Res. 40, 3495–3500 (2000).
[CrossRef] [PubMed]

N. Scott-Samuel, A. Smith, “Greater than the sum of its parts: first- and second-order stimuli combine to improve perceptual accuracy for both motion and form,” Invest. Ophthalmol. Visual Sci. Suppl. 40, S425 (1999).

Scott-Samuel, N. E.

N. E. Scott-Samuel, M. A. Georgeson, “Does early non-linearity account for second-order motion?” Vision Res. 39, 2853–2865 (1999).
[CrossRef] [PubMed]

Silverman, G.

S. P. McKee, G. Silverman, K. Nakayama, “Precise velocity discrimination despite random variations in temporal frequency and contrast,” Vision Res. 26, 609–619 (1986).
[CrossRef] [PubMed]

Smith, A.

N. Scott-Samuel, A. Smith, “No local cancellation between directionally opposed first-order and second-order motion signals,” Vision Res. 40, 3495–3500 (2000).
[CrossRef] [PubMed]

N. Scott-Samuel, A. Smith, “Greater than the sum of its parts: first- and second-order stimuli combine to improve perceptual accuracy for both motion and form,” Invest. Ophthalmol. Visual Sci. Suppl. 40, S425 (1999).

Smith, A. T.

T. Ledgeway, A. T. Smith, “Changes in perceived speed following adaptation to first-order and second-order motion,” Vision Res. 37, 215–224 (1997).
[CrossRef] [PubMed]

A. T. Smith, T. Ledgeway, “Separate detection of moving luminance and contrast modulations: fact or artifact?” Vision Res. 37, 45–62 (1997).
[CrossRef] [PubMed]

T. Ledgeway, A. T. Smith, “Evidence for separate motion-detecting mechanisms for first- and second-order motion in human vision,” Vision Res. 34, 2727–2740 (1994).
[CrossRef] [PubMed]

A. T. Smith, “The detection of second-order motion,” in Visual Detection of Motion, A. T. Smith, R. J. Snowden, eds. (Academic, London, 1994), pp. 145–176.

Sperling, G.

C. Chubb, G. Sperling, “Two motion perception mechanisms revealed through distance-driven reversal of apparent motion,” Proc. Natl. Acad. Sci. USA 86, 2985–2989 (1989).
[CrossRef] [PubMed]

C. Chubb, G. Sperling, “Drift-balanced random stimuli: a general basis for studying non-Fourier motion perception,” J. Opt. Soc. Am. A 5, 1986–2006 (1988).
[CrossRef] [PubMed]

Thomas, J.

Turano, K.

K. Turano, A. Pantle, “On the mechanism that encodes the movement of contrast variations: velocity discrimination,” Vision Res. 29, 207–221 (1989).
[CrossRef] [PubMed]

West, S.

G. Mather, S. West, “Evidence for second-order motion detectors,” Vision Res. 33, 1109–1112 (1993).
[CrossRef] [PubMed]

Wilson, H. R.

L.-M. Lin, H. R. Wilson, “Fourier and non-Fourier pattern discrimination compared,” Vision Res. 36, 1907–1918 (1996).
[CrossRef] [PubMed]

H. R. Wilson, V. P. Ferrera, C. Yo, “A psychophysically motivated model for two-dimensional motion perception,” Visual Neurosci. 9, 79–97 (1992).
[CrossRef]

Wolf, J. D.

G. Orban, J. D. Wolf, H. Maes, “Factors influencing velocity coding in the human visual system,” Vision Res. 24, 33–39 (1984).
[CrossRef] [PubMed]

Yo, C.

H. R. Wilson, V. P. Ferrera, C. Yo, “A psychophysically motivated model for two-dimensional motion perception,” Visual Neurosci. 9, 79–97 (1992).
[CrossRef]

Brain

D. Regan, S. Bartol, T. Murray, K. Beverley, “Spatial frequency discrimination in normal vision and in patients with multiple sclerosis,” Brain 105, 735–754 (1982).
[CrossRef] [PubMed]

Invest. Ophthalmol. Visual Sci. Suppl.

N. Scott-Samuel, A. Smith, “Greater than the sum of its parts: first- and second-order stimuli combine to improve perceptual accuracy for both motion and form,” Invest. Ophthalmol. Visual Sci. Suppl. 40, S425 (1999).

J. Opt. Soc. Am.

J. Opt. Soc. Am. A

J. Physiol.

F. W. Campbell, J. G. Robson, “Application of Fourier analysis to the visibility of gratings,” J. Physiol. 197, 551–566 (1968).
[PubMed]

Nature

B. Julesz, “Textons, the elements of texture perception, and their interactions,” Nature 290, 91–97 (1981).
[CrossRef] [PubMed]

Proc. Natl. Acad. Sci. USA

C. Chubb, G. Sperling, “Two motion perception mechanisms revealed through distance-driven reversal of apparent motion,” Proc. Natl. Acad. Sci. USA 86, 2985–2989 (1989).
[CrossRef] [PubMed]

Vision Res.

G. Mather, S. West, “Evidence for second-order motion detectors,” Vision Res. 33, 1109–1112 (1993).
[CrossRef] [PubMed]

T. Ledgeway, A. T. Smith, “Evidence for separate motion-detecting mechanisms for first- and second-order motion in human vision,” Vision Res. 34, 2727–2740 (1994).
[CrossRef] [PubMed]

A. T. Smith, T. Ledgeway, “Separate detection of moving luminance and contrast modulations: fact or artifact?” Vision Res. 37, 45–62 (1997).
[CrossRef] [PubMed]

S. Nishida, T. Ledgeway, M. Edwards, “Dual multiple-scale processing for motion in the human visual system,” Vision Res. 37, 2685–2698 (1997).
[CrossRef] [PubMed]

N. E. Scott-Samuel, M. A. Georgeson, “Does early non-linearity account for second-order motion?” Vision Res. 39, 2853–2865 (1999).
[CrossRef] [PubMed]

R. Gray, D. Regan, “Spatial frequency discrimination and detection characteristics for gratings defined by orientation texture,” Vision Res. 38, 2601–2617 (1998).
[CrossRef]

A. M. Derrington, D. R. Badcock, “Separate detectors for simple and complex patterns?” Vision Res. 25, 1869–1878 (1985).
[CrossRef]

H. Northdurft, “Orientation sensitivity and texture segmentation in patterns with different line orientation,” Vision Res. 25, 551–560 (1985).
[CrossRef]

A. J. Schofield, M. A. Georgeson, “Sensitivity to modulations of luminance and contrast in visual white noise: separate mechanisms with similar behaviour,” Vision Res. 39, 2697–2716 (1999).
[CrossRef] [PubMed]

S. F. Bowne, “Contrast discrimination cannot explain spatial frequency, orientation or temporal frequency resolution,” Vision Res. 30, 449–461 (1990).
[CrossRef]

L.-M. Lin, H. R. Wilson, “Fourier and non-Fourier pattern discrimination compared,” Vision Res. 36, 1907–1918 (1996).
[CrossRef] [PubMed]

S. P. McKee, G. Silverman, K. Nakayama, “Precise velocity discrimination despite random variations in temporal frequency and contrast,” Vision Res. 26, 609–619 (1986).
[CrossRef] [PubMed]

G. Orban, J. D. Wolf, H. Maes, “Factors influencing velocity coding in the human visual system,” Vision Res. 24, 33–39 (1984).
[CrossRef] [PubMed]

S. C. Panish, “Velocity discrimination at constant multiples of threshold contrast,” Vision Res. 28, 193–201 (1988).
[CrossRef] [PubMed]

K. Turano, A. Pantle, “On the mechanism that encodes the movement of contrast variations: velocity discrimination,” Vision Res. 29, 207–221 (1989).
[CrossRef] [PubMed]

S. J. Cropper, “Velocity discrimination in chromatic gratings and beats,” Vision Res. 34, 41–48 (1994).
[CrossRef] [PubMed]

A. Johnston, C. P. Benton, “Speed discrimination thresholds for first- and second-order bars and edges,” Vision Res. 37, 2217–2226 (1997).
[CrossRef] [PubMed]

N. Scott-Samuel, A. Smith, “No local cancellation between directionally opposed first-order and second-order motion signals,” Vision Res. 40, 3495–3500 (2000).
[CrossRef] [PubMed]

T. Ledgeway, “Adaptation to second-order motion results in a motion aftereffect for directionally-ambiguous test stimuli,” Vision Res. 34, 2879–2889 (1994).
[CrossRef] [PubMed]

T. Ledgeway, A. T. Smith, “Changes in perceived speed following adaptation to first-order and second-order motion,” Vision Res. 37, 215–224 (1997).
[CrossRef] [PubMed]

Visual Neurosci.

H. R. Wilson, V. P. Ferrera, C. Yo, “A psychophysically motivated model for two-dimensional motion perception,” Visual Neurosci. 9, 79–97 (1992).
[CrossRef]

Other

A. T. Smith, “The detection of second-order motion,” in Visual Detection of Motion, A. T. Smith, R. J. Snowden, eds. (Academic, London, 1994), pp. 145–176.

D. Regan, Human Perception of Objects (Sinauer, Sunderland, Mass., 2000).

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Figures (4)

Fig. 1
Fig. 1

Luminance and contrast modulations of the type used in the experiments. Both have a carrier consisting of static two-dimensional noise that has been high-pass filtered with a cutoff one octave above the grating spatial frequency. The waveforms beneath the gratings show luminance as a function of position for a one-dimensional horizontal slice through each image.

Fig. 2
Fig. 2

Psychometric functions obtained for one subject in the CM only condition of Experiment 1. The plots show, for nine different contrast modulation depths, the proportion of trials in which the subject reported that a comparison grating of the spatial frequency shown on the abscissa appeared to have a higher spatial frequency than a standard of 1 c/deg.

Fig. 3
Fig. 3

Results of Experiment 1 (spatial frequency discrimination) expressed as Weber fractions. (a) Spatial frequency Weber fractions in the LM alone (solid circles) and LM + 100% CM (open circles) conditions (see text for details). Results are shown separately for two subjects. (b) Weber fractions in the CM alone and CM + matched LM conditions for the same two subjects. Note that the range of the abscissa is different for the two subjects in both (a) and (b).

Fig. 4
Fig. 4

Results of Experiment 2 (speed frequency discrimination) expressed as Weber fractions. (a) Speed frequency Weber fractions in the LM alone (solid circles) and LM + 100% CM (open circles) conditions. (b) Weber fractions in the CM alone and CM + matched LM conditions.

Equations (2)

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y=a/xb+c,
y=100/[1+e(a-x)/b],

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