Auditory Localization of Clicks

Abstract

Previous investigations on the auditory localization of sounds have established that interaural differences in time and in intensity are both important. There have also been attempts to set temporal and intensive differences against each other, so that a lead in time at one ear accompanied by an increase in intensity at the other ear would cause a sound to be localized in the midline. On the basis of hypotheses suggested by physiological observations, two experiments were carried out. The first showed that the intensive difference required to offset a difference in time at the two ears depends upon the level of the sounds. Clicks at low level require smaller differences in intensity to offset a given temporal difference than do clicks at a high level. The relation between intensive differences (decibels) and temporal differences (microseconds) is not linear at any of the levels studied. In the second experiment, high-frequency masking noise interfered with reception in the basal turn of the cochlea. Although this noise did not mask the clicks, it produced a temporal lag that required compensation by a time delay at the opposite ear. The relations between these psychophysical results and physiological findings are discussed.