V. O'Brien, J. Opt. Soc. Am. 48, 112 (1958).
T. N. Cornsweet and D. Y. Teller, J. Opt. Soc. Am. 55, 1303 (1965).
M. Davidson and J. A. Whiteside, J. Opt. Soc. Am. 61, 530 (1971).
J. P. Thomas, Vision Res. 8, 49 (1968).
J. P. Thomas, Psychol. Rev. 77, 121 (1970). We have modified the equation slightly.
G. Westheimer, J. Physiol. (London) 190, 139 (1967).
G. von Bekesy, J. Opt. Soc. Am. 50, 1060 (1960).
O. Bryngdahl, Vision Res. 6, 553 (1966).
D. Y. Teller and B. Lindsey, Vision Res. 10, 1045 (1970).
A. S. Patel, J. Opt. Soc. Am. 56, 689 (1966).
J. I. Markoff and J. F. Sturr, J. Opt. Soc. Am. 61, 1530 (1971).
G. A. Fry, Am. J. Optom. Arch. Am. Acad. Optom. 25, 162 (1948).
M. Alpern, J. Opt. Soc. Am. 43, 648 (1953).
N. Weisstein and R. Growney, Percept. Psychophys. 5, 321 (1969).
N. Weisstein, in Visual Psychophysics, edited by D. Jameson and L. M. Hurvich (Springer, Heidelberg, 1972). The hypothesis that metacontrast is a cortical interaction is supported by the dichoptic transfer of the effect, the time delay for which the mask is most effective, and the dependence of metacontrast on both target and mask as patterns.
S. I. Cox, W. N. Dember, and M. F. Sherrick, Psychon. Sci. 17, 205 (1969).
W. R. Uttal, Percept. Psychophys. 7, 321 (1970).
M. S. Mayzner and M. E. Tresselt, Psychon. Sci. 17, 77 (1969).
S. S. Stevens, Percept. Psychophys. 1, 96 (1966).
P. H. Schiller and M. C. Smith, Percept. Psychophys. 3, 237 (1968).
What is strictly appropriate for measuring the variability of a geometric mean is a standard deviation computed with the log data, analogous to the computation of the geometric mean. The standard deviations computed in this manner are quite small, however, and can be misleading in describing the actual variability of the data; the range of standard deviation is considerably compressed.
This approximation can be obtained by taking the derivative of the convolution integral (see introduction) at a particular point, p, at the edge of the target [we assumed θ(- x) =θ(x)]. We solved for the weighting function so that [Equations], where dR is approximated by the difference between the magnitude estimations (ME2-ME1) corresponding to the change of distance along one dimension, x, and where dx is approximated by the difference between two successive mask sizes (M2-M1). See Thomas (Ref. 4) for a similar procedure.
T. N. Cornsweet, Visual Perception (Academic, New York, 1970).
On the other hand, the edge mechanism involved in brightness might require a smaller target as an impulse function, or generally, metacontrast might not be an edge effect at all but a function of some larger detector cell for brightness. In either case, under the assumption of linearity, as targets get narrower and approach the width of an impulse, the computed functions should approach the actual weighting function.
A. G. Goldstein, Percept. Psychophys. 7, 28 (1970).
H. H. Matteson, J. Opt. Soc. Am. 59, 1461 (1969).
F. Ratliff, Mach Bands: Quantitative Studies on Neural Networks in the Retina (Holden-Day, San Francisco, 1965).
G. Sperling, Percept. Psychophys. 8, 143 (1970).
M. S. Mayzner, M. H. Blatt, W. H. Bushsbaum, R. T. Friedel, P. E. Goodwin, D. Kanon, A. Kelman, and W. D. Nilsson, Psychon. Sci. 3, 79 (1965).
D. H. Hubel and T. N. Wiesel, J. Physiol. (London) 195, 215 (1968).