Abstract

Loudness adaptation was measured using the classic simultaneous, dichotic loudness balance technique. A 6-min continuous tone was introduced using headphones to a participant's adapting ear. Immediately upon presentation of the tone and at 1-min intervals, participants adjusted the sound level of a tone of the same frequency in the contralateral control ear until both tones sounded equally loud. The control ear, which was otherwise retained in silence, measured adaptation in the adapting ear. As the constant-sound level stimulus to the adapting ear continued, the sound level that a participant selected to produce equal loudness between ears decreased, oscillating towards an apparent asymptotic value. This value was used to calculate total decibels of adaptation. The magnitude of female adaptation exceeded that of males at all time points measured following stimulus onset. The ratio total dB of adaptation to dB SL of the test tone may provide an empirical estimate for the loudness exponent, n, seen in Stevens' power law, L=kphi(n), which relates the intensity of a pure tone, phi, to the loudness of the tone, L. Since dB of adaptation for females was greater than that of males, female n-values exceeded those of males, in accordance with previous research.