Psychophysical measurement methods.

Abstract

During the nine years 1 since the latest review of psychophysical measurement methods by Rich (120), the growth of interest in this field has suffered no relapse. New methods, refinements and generalizations of old ones, and applications of psychophysical principles to an ever widening range of problems, both theoretical and practical, have marked the period. We shall take up in order the following topics: The Comparison of Psychophysical Methods, The Method of Single Stimuli, Categories of Judgment, Special Influences upon the Judgment, Statistical Considerations, General and Theoretical Considerations, and New Applications.Comparison of Psychophysical Methods.Among the major papers on the comparison of psychophysical methods was that of Kellogg (83) in which an effort was made to determine the relationship between the methods of average error and constant stimuli. Kellogg wished to set up equations whereby the values obtained by one method could be related to those of the other, and to determine which method was the ' better ' by the criteria of reliability, accuracy, magnitude of sensitivity values yielded, and applicability to the study of Weber's law. Assuming that the method of average error gave no limen, Kellogg treated his results in terms of the variable error (VE) and constant error (CE) provided by each method, the intermediate category of judgment having been excluded from the method of constant stimuli. In general the VE's and CE's of constant stimuli were larger than those of average error, the differences

Shifts of the psychometric function: Distinguishing bias from perceptual effects

“…This format was a defining component of MOCS at the time (Urban, 1910), and it was also thoroughly described by Guilford (1954) and Woodworth and Schlosberg (1954). Yet, it was abandoned before formal analyses could have been used to resolve the empirical controversies created by discrepant results obtained with MOCS (under the two-or three-response formats) and with the method of limits (for a thorough discussion of these controversies, see Irwin, 1935). 8 Nowadays, almost all experiments in visual psychophysics involve the two-response format (for rare exceptions other than those already cited, see Figure 6.…”

Differences in visual acuity measurements obtained with different types of targets.

“…Additional background on applied psychophysical methods in general may be found in Irwin (13), Jones (14), Preston (18), and Rich (20). Guilford (11) briefiy treated the history of the constant methods and described the Muller-Urban method.…”

The comparison of a series of proportions: the problem and a new solution.

“…In spite of criticism by Thompson (11) and Culler (6), at last report he seemed to be standing pat nevertheless (13), (The literature is very controversial. Irwin [9] surveys some of the arguments.) Thompson's own derivation (11) was an attempt to find the errors of the constants from the theoretical errors of the various proportions experimentally observed.…”