Prediction of individual loudness exponents from cross-modality matching

An investigation of the relation among individual power-function exponents for 51 adults with normal hearing was undertaken. Three different psychophysical procedures were employed: absolute magnitude estimation (AME), absolute magnitude production (AMP), and cross-modality matching (CMM) between loudness and perceived length. From these procedures, loudness exponents obtained directly from measurements of AME and AMP of loudness were compared to exponents predicted from CMM and AME of perceived length. The means of the distributions of measured and predicted exponents were found to have an identical value of 0.56. Moreover, more than half of the differences between the predicted and measured exponents ranged from -.07 to +.09, giving measured deviations that extend from -12.5 to 16%. The close agreement between the measured and predicted means, ranges, and distributions of exponent values implies that CMM combined with line-length information can be used with success to determine an individual's rate of loudness growth.