A COMPOSITE RANDOMIZATION PROCEDURE FOR MEASURING SPECTRAL SHAPE-DISCRIMINATION

In studies of auditory profile analysis [D. M. Green, Profile Analysis : Auditory Intensity Discrimination (Oxford U. P., New York, 1988)], t he sounds are presented at random levels to discourage the listener fr om basing the discrimination on a difference in absolute level rather than on a difference in the shape of the spectrum. A difference in abs olute level, however, can still provide an effective discrimination cu e if the difference is comparable to the range of randomization. Using enormous ranges of random levels is not desirable, because it is dist racting to normal listeners and may exceed the dynamic range of hearin g for listeners with hearing loss. This article describes a new experi mental procedure which permits the experimenter to greatly reduce the range of level randomization in roving-level tasks.