Lateralization vs Localization

Abstract

As we all know, sounds heard through earphones appear to be inside our head instead of “out there.” Because of this, many investigators use the term “lateralization” for the spatial aspects of such sounds and reserve “localization” for sounds from external sources. The present study finds the distinction unnecessary. Subjects listening to bursts of wide-band noise through earphones were asked to indicate where the sound would have come from if its source were external. To aid him in this judgment, small lamps were placed at 15° intervals in the horizontal plane around the subject. He was provided with a switch with which he could light any one of the lamps which then flashed in synchronism with the sound. His task was to select the lamp which most nearly represented the direction of the imaginary sound source. Interaural time differences appropriate to the various directions were provided by a delay line. The results show that subjects can make this judgment from the start with little difficulty, that their performances compare favorably with localization judgments based on sound from external sources, and that practice and prompting do not improve their accuracy. (This work was partially supported by the Bureau of Ships.)