Loudness adaptation: resolution of a psychophysical enigma

Traditional measurement of loudness adaptation based on binaural matching has been challenged by Scharf (1983) and others as an artifact of binaural interaction due to contrast effects. Weiler, Sandman, and Pederson (1981) addressed this problem by developing a monaural technique called the ipsilateral comparison paradigm (ICP), which demonstrates strong adaptation effects within the auditory system. The two experiments described in this report support the meaningfulness of that procedure. They show that the ICP is not confounded by psychophysical contrast as suggested by Canevet, Scharf, and Botte (1983); they also demonstrate that the results obtained with the ICP are robust--adaptation effects were noted across a broad range of intensities and were similar when psychophysical reports were made by magnitude estimation and graphic rating means.