Theory of binaural interaction based in auditory-nerve data. IV. A model for subjective lateral position.

A model for the subjective lateral position of 500-Hz tones is presented and compared with experimental lateralization data. Previous papers in this series have explicitly described the auditory-nerve response to these stimuli and proposed a binaural displayer that interaurally compares the auditory-nerve firing times. The outputs of the displayer are postulated to represent the only information about detailed firing times that is available to the brain. In the present paper, lateral-position predictions are obtained by a central nonoptimal weighting of these outputs that depends on the interaural intensity difference of the tone. These predictions describe the results of lateralization-matching experiments more accurately and over a wider range of stimulus conditions than previous theories, except for those results which suggest that low-frequency binaural tones can generate multiple perceptual images. The predictions of our model are also consistent with the results of centering and laterality-comparison experiments. It is argued that the data discussed in this paper are generally incompatible with theories that propose a peripheral interaction of interaural timing and intensity information such as the latency hypothesis.