Ipsilateral loudness adaptation over multiple intensity levels

Could monaural loudness adaptation be a simple artifact of psychophysical c ontrast? From adaptation data based on the Ipsilateral Comparison Paradigm (ICP), A. J. Dange, J. S. Warm, E. M. Weller, and W. N. Dember (1993) concl uded that loudness adaptation was not an artifact of psychophysical contras t, but their conclusion was dependent on results from one intensity. This s tudy, involving multiple intensities, re-examined the issue of contrast ver sus adaptation and generally supported the conclusions of Dange et al. The results also showed an unexpected asymmetry of adaptation based on the dire ction of the referent modulation used with the ICP technique. Some implicat ions are discussed.