Intensity perception XI. Experimental results on the relation of intensity resolution to loudness matching.

According to a recent extension of our theory of intensity perception [Lim et al., J. Acoust. Soc. Am 62, 1256-1267 (1977)], two stimuli are matched in loudness if and only if their intensities divide the respective dynamic ranges proportionally in terms of just noticeable differences. This study reports results of intensity discrimination and loudness matching experiments designed to test this prediction. Data were obtained over most of the dynamic range for three different types of sounds: a 1000-Hz tone in quiet, a 1000-Hz tone partially masked by a 2-octave band of noise, and spectrally flat wide-band noise. Of the five subjects tested, three produced results that had sufficient internal consistency to be useful for testing the predictions. For these subjects, the data and the theory were found to be reasonably consistent. Comparison with other studies, however, reveals that loudness matching results vary with matching paradigm by an amount that is significant with respect to the task of evaluating the theory. Hence, a rigorous test of the theory requires an improved understanding of the effects of matching paradigm.