Inability of Listeners to Trade Completely Interaural Time for Interaural Intensity in a Detection Task

The classical “binaural trading ratio” measures a supposed trade of interaural temporal discrepancies for opposing differences in interaural intensity. Implicit in these measures is the assumption that information is somehow transposed from one dimension, either time or intensity, to the other; if this is so, then the constraint of a time-to-intensity or intensity-to-time conversion must be placed on any viable model of binaural interaction. The information-conversion assumption implies that a tone centered by opposing time with intensity will not be detectably different from a diotic tone. We tested this assertion using 500-Hz, 125-msec tone bursts. For a given value of Δt a subject was tested over a wide range of ΔI's. For all values ΔI, subjects were able to detect differences between the test tones and diotic tones of the same frequency and duration.