Dange et al. [J. Gen. Psychol. 120, 217--244 (1993)] investigated Weiler's ipsilateral comparison paradigm (ICP) and determined that the results could not be explained as a function of simple auditory contrast. This study introduces a mixed referent condition, wherein increasing and decreasing referents alternate in the same trial. Results from all conditions demonstrated that both base and referent tones adapt under both levels of intensity (50 and 70 dB). If contrast were the dominant influence, adaptation would not be expected in mixed or decreasing referent conditions, nor should the referents themselves adapt. Thus contrast would not explain the results. However, certain preliminary post hoc analyses may reveal an influence due to contrast. Alternately, the simple referent conditions show correspondence with a model for binaural adaptation [Weiler and Hood, Audiology 16, 499--506 (1977)]. This analysis shows that the average for simple referent ICP adaptation differs from binaural adaptation only by a power of 2.