Role of Stimulus Frequency in the Phenomenon of Localization Shifts

Abstract

The apparent location of a sound in space can be influenced by the monaural presentation of a second auditory stimulus. The extent to which the localization shift occurs has been shown to be related to the frequency and intensity relations between the two auditory stimuli [R. A. Butler and R. F. Naunton, J. Acoust. Soc. Am. 34, 1100 (1962)]. The results of additional experiments have described in greater detail the importance of frequency relations between the two stimuli. In these experiments, the sound in space (signal) was either 0.5, 1, 2, 4 or 8 kc/sec and the frequency of the monaural stimulus (interference) ranged from three octaves below to one octave above that of the signal. Three loudness-level relations between signal and interference were also employed: 40:80, 10:50 and 10:20 phons. The results demonstrated that the signal localization shift is greatest when the frequency difference between signal and interference is least, and increases as the loudness level of the interference stimulus is increased. [Work supported by funds provided under contracts NB 04508-01 and NB 03815-03 with the National Institutes of Health, U. S. Department of Health, Education and Welfare.]