title: Achieving across-laboratory replicability in psychophysical scaling.
abstract: It is well known that, although psychophysical scaling produces good qualitative agreement between experiments, precise quantitative agreement between experimental results, such as that routinely achieved in physics or biology, is rarely or never attained. A particularly galling example of this is the fact that power function exponents for the same psychological continuum, measured in different laboratories but ostensibly using the same scaling method, magnitude estimation, can vary by a factor of three. Constrained scaling (CS), in which observers first learn a standardized meaning for a set of numerical responses relative to a standard sensory continuum and then make magnitude judgments of other sensations using the learned response scale, has produced excellent quantitative agreement between individual observers' psychophysical functions. Theoretically it could do the same for across-laboratory comparisons, although this needs to be tested directly. We compared nine different experiments from four different laboratories as an example of the level of across experiment and across-laboratory agreement achievable using CS. In general, we found across experiment and across-laboratory agreement using CS to be significantly superior to that typically obtained with conventional magnitude estimation techniques, although some of its potential remains to be realized.
authors.affiliation: Department of Psychology and Brain Research Centre, University of British Columbia, Vancouver BC, Canada.
authors.forename: Lawrence M
authors.initials: LM
authors.lastname: Ward
authors.affiliation: Career Centre, University of the Fraser Valley, Abbottsford BC, Canada.
authors.forename: Michael
authors.initials: M
authors.lastname: Baumann
authors.affiliation: Interaxon, Toronto ON, Canada.
authors.forename: Graeme
authors.initials: G
authors.lastname: Moffat
authors.affiliation: Department of Psychology, McMaster University, Hamilton ON, Canada.
authors.forename: Larry E
authors.initials: LE
authors.lastname: Roberts
authors.affiliation: Department of Informatics, Kyushu University Fukuoka, Japan.
authors.forename: Shuji
authors.initials: S
authors.lastname: Mori
authors.affiliation: Cognitiva Information Science Institute, Gatineau QU, Canada.
authors.forename: Matthew
authors.initials: M
authors.lastname: Rutledge-Taylor
authors.affiliation: Department of Cognitive Science, Carleton University, Ottawa ON, Canada.
authors.forename: Robert L
authors.initials: RL
authors.lastname: West
keywords: constrained scaling; loudness; power function exponents; psychological measurement; psychophysical scaling