Just Noticeable Differences for Changes of Interaural Time Differences as a Function of Interaural Time Differences

Abstract

The just noticeable differences for changes of interaural time differences between two bursts of noise were investigated as a function of the interaural time difference of the first (reference) burst. Four normal hearing subjects listened through earphones to time differences between ears which were varied by electrical means. The noise went through a low-pass filter set at 1300 cps and had an intensity of 70 db SPL. The bursts were 0.85 second in duration. Interaural time differences for the reference bursts were between 0 and 600 μsec, with just noticeable differences increasing from 12 to 21 μsec, respectively, in an exponentially increasing manner. These just noticeable differences correspond to 75% correct judgements in the symmetrical two-choice tests. Group and individual thresholds and their distributions are presented. [This paper represents a report of a Master's thesis submitted to Western Reserve University, Cleveland, Ohio (January, 1958). The author is indebted to Professor Earl D. Schubert, Coordinator of Research of the Cleveland Hearing and Speech Center, for generous guidance.]