On measuring the DL for pitch memory with the transformed up-down psychophysical method

Abstract

Traditionally, the difference limen for pitch memory has been determined by generating a psychometric function with the method of constant stimulus differences. This paper discusses the application of a more efficient psychophysical technique to the measurement of the pitch DL. In this experiment, the listeners were instructed to identify which of two tones in a two-alternative forced-choice paradigm was higher in pitch. Threshold was defined as that frequency difference necessary for 79.4% correct discrimination. This performance level was determined with the transformed up-down strategy [Levitt, J. Acoust. Soc. Am. 49, 467–477 (1971)]. During the up-down testing, the variable frequency was increased and decreased in equal ratio fashion by means of a programmable frequency synthesizer capable of providing six-digit resolution. The pitch DL's generated with this method were comparable to those measured with the more cumbersome method of constants [Harris, J. Acoust. Soc. Am. 40, 43–46 (1966)]. [Supported by V. A. Medical Research Project 7990-01.]